# IQueryable(T) Interface

**.NET Framework 4.5**

Provides functionality to evaluate queries against a specific data source wherein the type of the data is known.

**Namespace:**System.Linq

**Assembly:**System.Core (in System.Core.dll)

type IQueryable<'T> = interface interface IEnumerable<'T> interface IQueryable interface IEnumerable end

#### Type Parameters

- out T
The type of the data in the data source.

This type parameter is covariant. That is, you can use either the type you specified or any type that is more derived. For more information about covariance and contravariance, see Covariance and Contravariance in Generics.

The IQueryable(T) type exposes the following members.

Name | Description | |
---|---|---|

ElementType | Gets the type of the element(s) that are returned when the expression tree associated with this instance of IQueryable is executed. (Inherited from IQueryable.) | |

Expression | Gets the expression tree that is associated with the instance of IQueryable. (Inherited from IQueryable.) | |

Provider | Gets the query provider that is associated with this data source. (Inherited from IQueryable.) |

Name | Description | |
---|---|---|

GetEnumerator | Returns an enumerator that iterates through the collection. (Inherited from IEnumerable(T).) |

Name | Description | |
---|---|---|

Aggregate(T)(Func(T, T, T)) | Overloaded. Applies an accumulator function over a sequence. (Defined by Enumerable.) | |

Aggregate(TSource)(Expression(Func(TSource, TSource, TSource))) | Overloaded. Applies an accumulator function over a sequence. (Defined by Queryable.) | |

Aggregate(T, TAccumulate)(TAccumulate, Func(TAccumulate, T, TAccumulate)) | Overloaded. Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value. (Defined by Enumerable.) | |

Aggregate(TSource, TAccumulate)(TAccumulate, Expression(Func(TAccumulate, TSource, TAccumulate))) | Overloaded. Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value. (Defined by Queryable.) | |

Aggregate(T, TAccumulate, TResult)(TAccumulate, Func(TAccumulate, T, TAccumulate), Func(TAccumulate, TResult)) | Overloaded. Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value. (Defined by Enumerable.) | |

Aggregate(TSource, TAccumulate, TResult)(TAccumulate, Expression(Func(TAccumulate, TSource, TAccumulate)), Expression(Func(TAccumulate, TResult))) | Overloaded. Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value, and the specified function is used to select the result value. (Defined by Queryable.) | |

All(T)(Func(T, Boolean)) | Overloaded. Determines whether all elements of a sequence satisfy a condition. (Defined by Enumerable.) | |

All(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Determines whether all the elements of a sequence satisfy a condition. (Defined by Queryable.) | |

Any(T)() | Overloaded. Determines whether a sequence contains any elements. (Defined by Enumerable.) | |

Any(TSource)() | Overloaded. Determines whether a sequence contains any elements. (Defined by Queryable.) | |

Any(T)(Func(T, Boolean)) | Overloaded. Determines whether any element of a sequence satisfies a condition. (Defined by Enumerable.) | |

Any(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Determines whether any element of a sequence satisfies a condition. (Defined by Queryable.) | |

AsEnumerable(T) | Returns the input typed as IEnumerable(T). (Defined by Enumerable.) | |

AsParallel() | Overloaded. Enables parallelization of a query. (Defined by ParallelEnumerable.) | |

AsParallel(T)() | Overloaded. Enables parallelization of a query. (Defined by ParallelEnumerable.) | |

AsQueryable() | Overloaded. Converts an IEnumerable to an IQueryable. (Defined by Queryable.) | |

AsQueryable(T)() | Overloaded. Converts a generic IEnumerable(T) to a generic IQueryable(T). (Defined by Queryable.) | |

Average(T)(Func(T, Decimal)) | Overloaded. Computes the average of a sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Nullable(Decimal))) | Overloaded. Computes the average of a sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(TSource)(Expression(Func(TSource, Decimal))) | Overloaded. Computes the average of a sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Nullable(Decimal)))) | Overloaded. Computes the average of a sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(T)(Func(T, Double)) | Overloaded. Computes the average of a sequence of Double values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Nullable(Double))) | Overloaded. Computes the average of a sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(TSource)(Expression(Func(TSource, Double))) | Overloaded. Computes the average of a sequence of Double values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Nullable(Double)))) | Overloaded. Computes the average of a sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(T)(Func(T, Int32)) | Overloaded. Computes the average of a sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Nullable(Int32))) | Overloaded. Computes the average of a sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Int64)) | Overloaded. Computes the average of a sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Nullable(Int64))) | Overloaded. Computes the average of a sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Single)) | Overloaded. Computes the average of a sequence of Single values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(T)(Func(T, Nullable(Single))) | Overloaded. Computes the average of a sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Average(TSource)(Expression(Func(TSource, Int32))) | Overloaded. Computes the average of a sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Nullable(Int32)))) | Overloaded. Computes the average of a sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Single))) | Overloaded. Computes the average of a sequence of Single values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Nullable(Single)))) | Overloaded. Computes the average of a sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Int64))) | Overloaded. Computes the average of a sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Average(TSource)(Expression(Func(TSource, Nullable(Int64)))) | Overloaded. Computes the average of a sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Cast(TResult)() | Overloaded. Converts the elements of an IQueryable to the specified type. (Defined by Queryable.) | |

Cast(TResult)() | Overloaded. Casts the elements of an IEnumerable to the specified type. (Defined by Enumerable.) | |

Concat(T)(IEnumerable(T)) | Overloaded. Concatenates two sequences. (Defined by Enumerable.) | |

Concat(TSource)(IEnumerable(TSource)) | Overloaded. Concatenates two sequences. (Defined by Queryable.) | |

Contains(T)(T) | Overloaded. Determines whether a sequence contains a specified element by using the default equality comparer. (Defined by Enumerable.) | |

Contains(TSource)(TSource) | Overloaded. Determines whether a sequence contains a specified element by using the default equality comparer. (Defined by Queryable.) | |

Contains(T)(T, IEqualityComparer(T)) | Overloaded. Determines whether a sequence contains a specified element by using a specified IEqualityComparer(T). (Defined by Enumerable.) | |

Contains(TSource)(TSource, IEqualityComparer(TSource)) | Overloaded. Determines whether a sequence contains a specified element by using a specified IEqualityComparer(T). (Defined by Queryable.) | |

Count(T)() | Overloaded. Returns the number of elements in a sequence. (Defined by Enumerable.) | |

Count(TSource)() | Overloaded. Returns the number of elements in a sequence. (Defined by Queryable.) | |

Count(T)(Func(T, Boolean)) | Overloaded. Returns a number that represents how many elements in the specified sequence satisfy a condition. (Defined by Enumerable.) | |

Count(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the number of elements in the specified sequence that satisfies a condition. (Defined by Queryable.) | |

DefaultIfEmpty(T)() | Overloaded. Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty. (Defined by Enumerable.) | |

DefaultIfEmpty(TSource)() | Overloaded. Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty. (Defined by Queryable.) | |

DefaultIfEmpty(T)(T) | Overloaded. Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty. (Defined by Enumerable.) | |

DefaultIfEmpty(TSource)(TSource) | Overloaded. Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty. (Defined by Queryable.) | |

Distinct(T)() | Overloaded. Returns distinct elements from a sequence by using the default equality comparer to compare values. (Defined by Enumerable.) | |

Distinct(TSource)() | Overloaded. Returns distinct elements from a sequence by using the default equality comparer to compare values. (Defined by Queryable.) | |

Distinct(T)(IEqualityComparer(T)) | Overloaded. Returns distinct elements from a sequence by using a specified IEqualityComparer(T) to compare values. (Defined by Enumerable.) | |

Distinct(TSource)(IEqualityComparer(TSource)) | Overloaded. Returns distinct elements from a sequence by using a specified IEqualityComparer(T) to compare values. (Defined by Queryable.) | |

ElementAt(T)(Int32) | Overloaded. Returns the element at a specified index in a sequence. (Defined by Enumerable.) | |

ElementAt(TSource)(Int32) | Overloaded. Returns the element at a specified index in a sequence. (Defined by Queryable.) | |

ElementAtOrDefault(T)(Int32) | Overloaded. Returns the element at a specified index in a sequence or a default value if the index is out of range. (Defined by Enumerable.) | |

ElementAtOrDefault(TSource)(Int32) | Overloaded. Returns the element at a specified index in a sequence or a default value if the index is out of range. (Defined by Queryable.) | |

Except(T)(IEnumerable(T)) | Overloaded. Produces the set difference of two sequences by using the default equality comparer to compare values. (Defined by Enumerable.) | |

Except(TSource)(IEnumerable(TSource)) | Overloaded. Produces the set difference of two sequences by using the default equality comparer to compare values. (Defined by Queryable.) | |

Except(T)(IEnumerable(T), IEqualityComparer(T)) | Overloaded. Produces the set difference of two sequences by using the specified IEqualityComparer(T) to compare values. (Defined by Enumerable.) | |

Except(TSource)(IEnumerable(TSource), IEqualityComparer(TSource)) | Overloaded. Produces the set difference of two sequences by using the specified IEqualityComparer(T) to compare values. (Defined by Queryable.) | |

First(T)() | Overloaded. Returns the first element of a sequence. (Defined by Enumerable.) | |

First(TSource)() | Overloaded. Returns the first element of a sequence. (Defined by Queryable.) | |

First(T)(Func(T, Boolean)) | Overloaded. Returns the first element in a sequence that satisfies a specified condition. (Defined by Enumerable.) | |

First(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the first element of a sequence that satisfies a specified condition. (Defined by Queryable.) | |

FirstOrDefault(T)() | Overloaded. Returns the first element of a sequence, or a default value if the sequence contains no elements. (Defined by Enumerable.) | |

FirstOrDefault(TSource)() | Overloaded. Returns the first element of a sequence, or a default value if the sequence contains no elements. (Defined by Queryable.) | |

FirstOrDefault(T)(Func(T, Boolean)) | Overloaded. Returns the first element of the sequence that satisfies a condition or a default value if no such element is found. (Defined by Enumerable.) | |

FirstOrDefault(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found. (Defined by Queryable.) | |

GroupBy(T, TKey)(Func(T, TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function. (Defined by Enumerable.) | |

GroupBy(TSource, TKey)(Expression(Func(TSource, TKey))) | Overloaded. Groups the elements of a sequence according to a specified key selector function. (Defined by Queryable.) | |

GroupBy(T, TKey)(Func(T, TKey), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer. (Defined by Enumerable.) | |

GroupBy(TSource, TKey)(Expression(Func(TSource, TKey)), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer. (Defined by Queryable.) | |

GroupBy(T, TKey, TElement)(Func(T, TKey), Func(T, TElement)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function. (Defined by Enumerable.) | |

GroupBy(T, TKey, TResult)(Func(T, TKey), Func(TKey, IEnumerable(T), TResult)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. (Defined by Enumerable.) | |

GroupBy(TSource, TKey, TElement)(Expression(Func(TSource, TKey)), Expression(Func(TSource, TElement))) | Overloaded. Groups the elements of a sequence according to a specified key selector function and projects the elements for each group by using a specified function. (Defined by Queryable.) | |

GroupBy(TSource, TKey, TResult)(Expression(Func(TSource, TKey)), Expression(Func(TKey, IEnumerable(TSource), TResult))) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. (Defined by Queryable.) | |

GroupBy(T, TKey, TElement)(Func(T, TKey), Func(T, TElement), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a key selector function. The keys are compared by using a comparer and each group's elements are projected by using a specified function. (Defined by Enumerable.) | |

GroupBy(T, TKey, TResult)(Func(T, TKey), Func(TKey, IEnumerable(T), TResult), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The keys are compared by using a specified comparer. (Defined by Enumerable.) | |

GroupBy(TSource, TKey, TElement)(Expression(Func(TSource, TKey)), Expression(Func(TSource, TElement)), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence and projects the elements for each group by using a specified function. Key values are compared by using a specified comparer. (Defined by Queryable.) | |

GroupBy(TSource, TKey, TResult)(Expression(Func(TSource, TKey)), Expression(Func(TKey, IEnumerable(TSource), TResult)), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Keys are compared by using a specified comparer. (Defined by Queryable.) | |

GroupBy(T, TKey, TElement, TResult)(Func(T, TKey), Func(T, TElement), Func(TKey, IEnumerable(TElement), TResult)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function. (Defined by Enumerable.) | |

GroupBy(TSource, TKey, TElement, TResult)(Expression(Func(TSource, TKey)), Expression(Func(TSource, TElement)), Expression(Func(TKey, IEnumerable(TElement), TResult))) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. The elements of each group are projected by using a specified function. (Defined by Queryable.) | |

GroupBy(T, TKey, TElement, TResult)(Func(T, TKey), Func(T, TElement), Func(TKey, IEnumerable(TElement), TResult), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Key values are compared by using a specified comparer, and the elements of each group are projected by using a specified function. (Defined by Enumerable.) | |

GroupBy(TSource, TKey, TElement, TResult)(Expression(Func(TSource, TKey)), Expression(Func(TSource, TElement)), Expression(Func(TKey, IEnumerable(TElement), TResult)), IEqualityComparer(TKey)) | Overloaded. Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key. Keys are compared by using a specified comparer and the elements of each group are projected by using a specified function. (Defined by Queryable.) | |

GroupJoin(T, TInner, TKey, TResult)(IEnumerable(TInner), Func(T, TKey), Func(TInner, TKey), Func(T, IEnumerable(TInner), TResult)) | Overloaded. Correlates the elements of two sequences based on equality of keys and groups the results. The default equality comparer is used to compare keys. (Defined by Enumerable.) | |

GroupJoin(TOuter, TInner, TKey, TResult)(IEnumerable(TInner), Expression(Func(TOuter, TKey)), Expression(Func(TInner, TKey)), Expression(Func(TOuter, IEnumerable(TInner), TResult))) | Overloaded. Correlates the elements of two sequences based on key equality and groups the results. The default equality comparer is used to compare keys. (Defined by Queryable.) | |

GroupJoin(T, TInner, TKey, TResult)(IEnumerable(TInner), Func(T, TKey), Func(TInner, TKey), Func(T, IEnumerable(TInner), TResult), IEqualityComparer(TKey)) | Overloaded. Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer(T) is used to compare keys. (Defined by Enumerable.) | |

GroupJoin(TOuter, TInner, TKey, TResult)(IEnumerable(TInner), Expression(Func(TOuter, TKey)), Expression(Func(TInner, TKey)), Expression(Func(TOuter, IEnumerable(TInner), TResult)), IEqualityComparer(TKey)) | Overloaded. Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer(T) is used to compare keys. (Defined by Queryable.) | |

Intersect(T)(IEnumerable(T)) | Overloaded. Produces the set intersection of two sequences by using the default equality comparer to compare values. (Defined by Enumerable.) | |

Intersect(TSource)(IEnumerable(TSource)) | Overloaded. Produces the set intersection of two sequences by using the default equality comparer to compare values. (Defined by Queryable.) | |

Intersect(T)(IEnumerable(T), IEqualityComparer(T)) | Overloaded. Produces the set intersection of two sequences by using the specified IEqualityComparer(T) to compare values. (Defined by Enumerable.) | |

Intersect(TSource)(IEnumerable(TSource), IEqualityComparer(TSource)) | Overloaded. Produces the set intersection of two sequences by using the specified IEqualityComparer(T) to compare values. (Defined by Queryable.) | |

Join(T, TInner, TKey, TResult)(IEnumerable(TInner), Func(T, TKey), Func(TInner, TKey), Func(T, TInner, TResult)) | Overloaded. Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys. (Defined by Enumerable.) | |

Join(TOuter, TInner, TKey, TResult)(IEnumerable(TInner), Expression(Func(TOuter, TKey)), Expression(Func(TInner, TKey)), Expression(Func(TOuter, TInner, TResult))) | Overloaded. Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys. (Defined by Queryable.) | |

Join(T, TInner, TKey, TResult)(IEnumerable(TInner), Func(T, TKey), Func(TInner, TKey), Func(T, TInner, TResult), IEqualityComparer(TKey)) | Overloaded. Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer(T) is used to compare keys. (Defined by Enumerable.) | |

Join(TOuter, TInner, TKey, TResult)(IEnumerable(TInner), Expression(Func(TOuter, TKey)), Expression(Func(TInner, TKey)), Expression(Func(TOuter, TInner, TResult)), IEqualityComparer(TKey)) | Overloaded. Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer(T) is used to compare keys. (Defined by Queryable.) | |

Last(T)() | Overloaded. Returns the last element of a sequence. (Defined by Enumerable.) | |

Last(TSource)() | Overloaded. Returns the last element in a sequence. (Defined by Queryable.) | |

Last(T)(Func(T, Boolean)) | Overloaded. Returns the last element of a sequence that satisfies a specified condition. (Defined by Enumerable.) | |

Last(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the last element of a sequence that satisfies a specified condition. (Defined by Queryable.) | |

LastOrDefault(T)() | Overloaded. Returns the last element of a sequence, or a default value if the sequence contains no elements. (Defined by Enumerable.) | |

LastOrDefault(TSource)() | Overloaded. Returns the last element in a sequence, or a default value if the sequence contains no elements. (Defined by Queryable.) | |

LastOrDefault(T)(Func(T, Boolean)) | Overloaded. Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. (Defined by Enumerable.) | |

LastOrDefault(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the last element of a sequence that satisfies a condition or a default value if no such element is found. (Defined by Queryable.) | |

LongCount(T)() | Overloaded. Returns an Int64 that represents the total number of elements in a sequence. (Defined by Enumerable.) | |

LongCount(TSource)() | Overloaded. Returns an Int64 that represents the total number of elements in a sequence. (Defined by Queryable.) | |

LongCount(T)(Func(T, Boolean)) | Overloaded. Returns an Int64 that represents how many elements in a sequence satisfy a condition. (Defined by Enumerable.) | |

LongCount(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns an Int64 that represents the number of elements in a sequence that satisfy a condition. (Defined by Queryable.) | |

Max(T)() | Overloaded. Returns the maximum value in a generic sequence. (Defined by Enumerable.) | |

Max(TSource)() | Overloaded. Returns the maximum value in a generic IQueryable(T). (Defined by Queryable.) | |

Max(T)(Func(T, Decimal)) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum Decimal value. (Defined by Enumerable.) | |

Max(T)(Func(T, Nullable(Decimal))) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum nullable Decimal value. (Defined by Enumerable.) | |

Max(T)(Func(T, Double)) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum Double value. (Defined by Enumerable.) | |

Max(T)(Func(T, Nullable(Double))) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum nullable Double value. (Defined by Enumerable.) | |

Max(T)(Func(T, Int32)) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum Int32 value. (Defined by Enumerable.) | |

Max(T)(Func(T, Nullable(Int32))) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum nullable Int32 value. (Defined by Enumerable.) | |

Max(T)(Func(T, Int64)) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum Int64 value. (Defined by Enumerable.) | |

Max(T)(Func(T, Nullable(Int64))) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum nullable Int64 value. (Defined by Enumerable.) | |

Max(T)(Func(T, Single)) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum Single value. (Defined by Enumerable.) | |

Max(T)(Func(T, Nullable(Single))) | Overloaded. Invokes a transform function on each element of a sequence and returns the maximum nullable Single value. (Defined by Enumerable.) | |

Max(T, TResult)(Func(T, TResult)) | Overloaded. Invokes a transform function on each element of a generic sequence and returns the maximum resulting value. (Defined by Enumerable.) | |

Max(TSource, TResult)(Expression(Func(TSource, TResult))) | Overloaded. Invokes a projection function on each element of a generic IQueryable(T) and returns the maximum resulting value. (Defined by Queryable.) | |

Min(T)() | Overloaded. Returns the minimum value in a generic sequence. (Defined by Enumerable.) | |

Min(TSource)() | Overloaded. Returns the minimum value of a generic IQueryable(T). (Defined by Queryable.) | |

Min(T)(Func(T, Decimal)) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum Decimal value. (Defined by Enumerable.) | |

Min(T)(Func(T, Nullable(Decimal))) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum nullable Decimal value. (Defined by Enumerable.) | |

Min(T)(Func(T, Double)) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum Double value. (Defined by Enumerable.) | |

Min(T)(Func(T, Nullable(Double))) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum nullable Double value. (Defined by Enumerable.) | |

Min(T)(Func(T, Int32)) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum Int32 value. (Defined by Enumerable.) | |

Min(T)(Func(T, Nullable(Int32))) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum nullable Int32 value. (Defined by Enumerable.) | |

Min(T)(Func(T, Int64)) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum Int64 value. (Defined by Enumerable.) | |

Min(T)(Func(T, Nullable(Int64))) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum nullable Int64 value. (Defined by Enumerable.) | |

Min(T)(Func(T, Single)) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum Single value. (Defined by Enumerable.) | |

Min(T)(Func(T, Nullable(Single))) | Overloaded. Invokes a transform function on each element of a sequence and returns the minimum nullable Single value. (Defined by Enumerable.) | |

Min(T, TResult)(Func(T, TResult)) | Overloaded. Invokes a transform function on each element of a generic sequence and returns the minimum resulting value. (Defined by Enumerable.) | |

Min(TSource, TResult)(Expression(Func(TSource, TResult))) | Overloaded. Invokes a projection function on each element of a generic IQueryable(T) and returns the minimum resulting value. (Defined by Queryable.) | |

OfType(TResult)() | Overloaded. Filters the elements of an IQueryable based on a specified type. (Defined by Queryable.) | |

OfType(TResult)() | Overloaded. Filters the elements of an IEnumerable based on a specified type. (Defined by Enumerable.) | |

OrderBy(T, TKey)(Func(T, TKey)) | Overloaded. Sorts the elements of a sequence in ascending order according to a key. (Defined by Enumerable.) | |

OrderBy(TSource, TKey)(Expression(Func(TSource, TKey))) | Overloaded. Sorts the elements of a sequence in ascending order according to a key. (Defined by Queryable.) | |

OrderBy(T, TKey)(Func(T, TKey), IComparer(TKey)) | Overloaded. Sorts the elements of a sequence in ascending order by using a specified comparer. (Defined by Enumerable.) | |

OrderBy(TSource, TKey)(Expression(Func(TSource, TKey)), IComparer(TKey)) | Overloaded. Sorts the elements of a sequence in ascending order by using a specified comparer. (Defined by Queryable.) | |

OrderByDescending(T, TKey)(Func(T, TKey)) | Overloaded. Sorts the elements of a sequence in descending order according to a key. (Defined by Enumerable.) | |

OrderByDescending(TSource, TKey)(Expression(Func(TSource, TKey))) | Overloaded. Sorts the elements of a sequence in descending order according to a key. (Defined by Queryable.) | |

OrderByDescending(T, TKey)(Func(T, TKey), IComparer(TKey)) | Overloaded. Sorts the elements of a sequence in descending order by using a specified comparer. (Defined by Enumerable.) | |

OrderByDescending(TSource, TKey)(Expression(Func(TSource, TKey)), IComparer(TKey)) | Overloaded. Sorts the elements of a sequence in descending order by using a specified comparer. (Defined by Queryable.) | |

Reverse(T)() | Overloaded. Inverts the order of the elements in a sequence. (Defined by Enumerable.) | |

Reverse(TSource)() | Overloaded. Inverts the order of the elements in a sequence. (Defined by Queryable.) | |

Select(T, TResult)(Func(T, TResult)) | Overloaded. Projects each element of a sequence into a new form. (Defined by Enumerable.) | |

Select(T, TResult)(Func(T, Int32, TResult)) | Overloaded. Projects each element of a sequence into a new form by incorporating the element's index. (Defined by Enumerable.) | |

Select(TSource, TResult)(Expression(Func(TSource, TResult))) | Overloaded. Projects each element of a sequence into a new form. (Defined by Queryable.) | |

Select(TSource, TResult)(Expression(Func(TSource, Int32, TResult))) | Overloaded. Projects each element of a sequence into a new form by incorporating the element's index. (Defined by Queryable.) | |

SelectMany(T, TResult)(Func(T, IEnumerable(TResult))) | Overloaded. Projects each element of a sequence to an IEnumerable(T) and flattens the resulting sequences into one sequence. (Defined by Enumerable.) | |

SelectMany(T, TResult)(Func(T, Int32, IEnumerable(TResult))) | Overloaded. Projects each element of a sequence to an IEnumerable(T), and flattens the resulting sequences into one sequence. The index of each source element is used in the projected form of that element. (Defined by Enumerable.) | |

SelectMany(TSource, TResult)(Expression(Func(TSource, IEnumerable(TResult)))) | Overloaded. Projects each element of a sequence to an IEnumerable(T) and combines the resulting sequences into one sequence. (Defined by Queryable.) | |

SelectMany(TSource, TResult)(Expression(Func(TSource, Int32, IEnumerable(TResult)))) | Overloaded. Projects each element of a sequence to an IEnumerable(T) and combines the resulting sequences into one sequence. The index of each source element is used in the projected form of that element. (Defined by Queryable.) | |

SelectMany(T, TCollection, TResult)(Func(T, Int32, IEnumerable(TCollection)), Func(T, TCollection, TResult)) | Overloaded. Projects each element of a sequence to an IEnumerable(T), flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. The index of each source element is used in the intermediate projected form of that element. (Defined by Enumerable.) | |

SelectMany(T, TCollection, TResult)(Func(T, IEnumerable(TCollection)), Func(T, TCollection, TResult)) | Overloaded. Projects each element of a sequence to an IEnumerable(T), flattens the resulting sequences into one sequence, and invokes a result selector function on each element therein. (Defined by Enumerable.) | |

SelectMany(TSource, TCollection, TResult)(Expression(Func(TSource, Int32, IEnumerable(TCollection))), Expression(Func(TSource, TCollection, TResult))) | Overloaded. Projects each element of a sequence to an IEnumerable(T) that incorporates the index of the source element that produced it. A result selector function is invoked on each element of each intermediate sequence, and the resulting values are combined into a single, one-dimensional sequence and returned. (Defined by Queryable.) | |

SelectMany(TSource, TCollection, TResult)(Expression(Func(TSource, IEnumerable(TCollection))), Expression(Func(TSource, TCollection, TResult))) | Overloaded. Projects each element of a sequence to an IEnumerable(T) and invokes a result selector function on each element therein. The resulting values from each intermediate sequence are combined into a single, one-dimensional sequence and returned. (Defined by Queryable.) | |

SequenceEqual(T)(IEnumerable(T)) | Overloaded. Determines whether two sequences are equal by comparing the elements by using the default equality comparer for their type. (Defined by Enumerable.) | |

SequenceEqual(TSource)(IEnumerable(TSource)) | Overloaded. Determines whether two sequences are equal by using the default equality comparer to compare elements. (Defined by Queryable.) | |

SequenceEqual(T)(IEnumerable(T), IEqualityComparer(T)) | Overloaded. Determines whether two sequences are equal by comparing their elements by using a specified IEqualityComparer(T). (Defined by Enumerable.) | |

SequenceEqual(TSource)(IEnumerable(TSource), IEqualityComparer(TSource)) | Overloaded. Determines whether two sequences are equal by using a specified IEqualityComparer(T) to compare elements. (Defined by Queryable.) | |

Single(T)() | Overloaded. Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence. (Defined by Enumerable.) | |

Single(TSource)() | Overloaded. Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence. (Defined by Queryable.) | |

Single(T)(Func(T, Boolean)) | Overloaded. Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists. (Defined by Enumerable.) | |

Single(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists. (Defined by Queryable.) | |

SingleOrDefault(T)() | Overloaded. Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence. (Defined by Enumerable.) | |

SingleOrDefault(TSource)() | Overloaded. Returns the only element of a sequence, or a default value if the sequence is empty; this method throws an exception if there is more than one element in the sequence. (Defined by Queryable.) | |

SingleOrDefault(T)(Func(T, Boolean)) | Overloaded. Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition. (Defined by Enumerable.) | |

SingleOrDefault(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns the only element of a sequence that satisfies a specified condition or a default value if no such element exists; this method throws an exception if more than one element satisfies the condition. (Defined by Queryable.) | |

Skip(T)(Int32) | Overloaded. Bypasses a specified number of elements in a sequence and then returns the remaining elements. (Defined by Enumerable.) | |

Skip(TSource)(Int32) | Overloaded. Bypasses a specified number of elements in a sequence and then returns the remaining elements. (Defined by Queryable.) | |

SkipWhile(T)(Func(T, Boolean)) | Overloaded. Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. (Defined by Enumerable.) | |

SkipWhile(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. (Defined by Queryable.) | |

SkipWhile(T)(Func(T, Int32, Boolean)) | Overloaded. Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. The element's index is used in the logic of the predicate function. (Defined by Enumerable.) | |

SkipWhile(TSource)(Expression(Func(TSource, Int32, Boolean))) | Overloaded. Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements. The element's index is used in the logic of the predicate function. (Defined by Queryable.) | |

SortBy(T) | Specifies a sort order. (Defined by QueryExtensions.) | |

Sum(T)(Func(T, Decimal)) | Overloaded. Computes the sum of the sequence of Decimal values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Nullable(Decimal))) | Overloaded. Computes the sum of the sequence of nullable Decimal values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(TSource)(Expression(Func(TSource, Decimal))) | Overloaded. Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Nullable(Decimal)))) | Overloaded. Computes the sum of the sequence of nullable Decimal values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(T)(Func(T, Double)) | Overloaded. Computes the sum of the sequence of Double values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Nullable(Double))) | Overloaded. Computes the sum of the sequence of nullable Double values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(TSource)(Expression(Func(TSource, Double))) | Overloaded. Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Nullable(Double)))) | Overloaded. Computes the sum of the sequence of nullable Double values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(T)(Func(T, Int32)) | Overloaded. Computes the sum of the sequence of Int32 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Nullable(Int32))) | Overloaded. Computes the sum of the sequence of nullable Int32 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Int64)) | Overloaded. Computes the sum of the sequence of Int64 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Nullable(Int64))) | Overloaded. Computes the sum of the sequence of nullable Int64 values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Single)) | Overloaded. Computes the sum of the sequence of Single values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(T)(Func(T, Nullable(Single))) | Overloaded. Computes the sum of the sequence of nullable Single values that are obtained by invoking a transform function on each element of the input sequence. (Defined by Enumerable.) | |

Sum(TSource)(Expression(Func(TSource, Int32))) | Overloaded. Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Nullable(Int32)))) | Overloaded. Computes the sum of the sequence of nullable Int32 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Int64))) | Overloaded. Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Nullable(Int64)))) | Overloaded. Computes the sum of the sequence of nullable Int64 values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Single))) | Overloaded. Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Sum(TSource)(Expression(Func(TSource, Nullable(Single)))) | Overloaded. Computes the sum of the sequence of nullable Single values that is obtained by invoking a projection function on each element of the input sequence. (Defined by Queryable.) | |

Take(T)(Int32) | Overloaded. Returns a specified number of contiguous elements from the start of a sequence. (Defined by Enumerable.) | |

Take(TSource)(Int32) | Overloaded. Returns a specified number of contiguous elements from the start of a sequence. (Defined by Queryable.) | |

TakeWhile(T)(Func(T, Boolean)) | Overloaded. Returns elements from a sequence as long as a specified condition is true. (Defined by Enumerable.) | |

TakeWhile(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Returns elements from a sequence as long as a specified condition is true. (Defined by Queryable.) | |

TakeWhile(T)(Func(T, Int32, Boolean)) | Overloaded. Returns elements from a sequence as long as a specified condition is true. The element's index is used in the logic of the predicate function. (Defined by Enumerable.) | |

TakeWhile(TSource)(Expression(Func(TSource, Int32, Boolean))) | Overloaded. Returns elements from a sequence as long as a specified condition is true. The element's index is used in the logic of the predicate function. (Defined by Queryable.) | |

ToArray(T) | Creates an array from a IEnumerable(T). (Defined by Enumerable.) | |

ToDictionary(T, TKey)(Func(T, TKey)) | Overloaded. Creates a Dictionary(TKey, TValue) from an IEnumerable(T) according to a specified key selector function. (Defined by Enumerable.) | |

ToDictionary(T, TKey)(Func(T, TKey), IEqualityComparer(TKey)) | Overloaded. Creates a Dictionary(TKey, TValue) from an IEnumerable(T) according to a specified key selector function and key comparer. (Defined by Enumerable.) | |

ToDictionary(T, TKey, TElement)(Func(T, TKey), Func(T, TElement)) | Overloaded. Creates a Dictionary(TKey, TValue) from an IEnumerable(T) according to specified key selector and element selector functions. (Defined by Enumerable.) | |

ToDictionary(T, TKey, TElement)(Func(T, TKey), Func(T, TElement), IEqualityComparer(TKey)) | Overloaded. Creates a Dictionary(TKey, TValue) from an IEnumerable(T) according to a specified key selector function, a comparer, and an element selector function. (Defined by Enumerable.) | |

ToList(T) | Creates a List(T) from an IEnumerable(T). (Defined by Enumerable.) | |

ToLookup(T, TKey)(Func(T, TKey)) | Overloaded. Creates a Lookup(TKey, TElement) from an IEnumerable(T) according to a specified key selector function. (Defined by Enumerable.) | |

ToLookup(T, TKey)(Func(T, TKey), IEqualityComparer(TKey)) | Overloaded. Creates a Lookup(TKey, TElement) from an IEnumerable(T) according to a specified key selector function and key comparer. (Defined by Enumerable.) | |

ToLookup(T, TKey, TElement)(Func(T, TKey), Func(T, TElement)) | Overloaded. Creates a Lookup(TKey, TElement) from an IEnumerable(T) according to specified key selector and element selector functions. (Defined by Enumerable.) | |

ToLookup(T, TKey, TElement)(Func(T, TKey), Func(T, TElement), IEqualityComparer(TKey)) | Overloaded. Creates a Lookup(TKey, TElement) from an IEnumerable(T) according to a specified key selector function, a comparer and an element selector function. (Defined by Enumerable.) | |

Union(T)(IEnumerable(T)) | Overloaded. Produces the set union of two sequences by using the default equality comparer. (Defined by Enumerable.) | |

Union(TSource)(IEnumerable(TSource)) | Overloaded. Produces the set union of two sequences by using the default equality comparer. (Defined by Queryable.) | |

Union(T)(IEnumerable(T), IEqualityComparer(T)) | Overloaded. Produces the set union of two sequences by using a specified IEqualityComparer(T). (Defined by Enumerable.) | |

Union(TSource)(IEnumerable(TSource), IEqualityComparer(TSource)) | Overloaded. Produces the set union of two sequences by using a specified IEqualityComparer(T). (Defined by Queryable.) | |

Where(T)(Func(T, Boolean)) | Overloaded. Filters a sequence of values based on a predicate. (Defined by Enumerable.) | |

Where(TSource)(Expression(Func(TSource, Boolean))) | Overloaded. Filters a sequence of values based on a predicate. (Defined by Queryable.) | |

Where(T)(Func(T, Int32, Boolean)) | Overloaded. Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function. (Defined by Enumerable.) | |

Where(TSource)(Expression(Func(TSource, Int32, Boolean))) | Overloaded. Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function. (Defined by Queryable.) | |

Zip(T, TSecond, TResult)(IEnumerable(TSecond), Func(T, TSecond, TResult)) | Overloaded. Applies a specified function to the corresponding elements of two sequences, producing a sequence of the results. (Defined by Enumerable.) | |

Zip(TFirst, TSecond, TResult)(IEnumerable(TSecond), Expression(Func(TFirst, TSecond, TResult))) | Overloaded. Merges two sequences by using the specified predicate function. (Defined by Queryable.) |

The IQueryable(T) interface is intended for implementation by query providers.

This interface inherits the IEnumerable(T) interface so that if it represents a query, the results of that query can be enumerated. Enumeration forces the expression tree associated with an IQueryable(T) object to be executed. Queries that do not return enumerable results are executed when the Execute(TResult)(Expression) method is called.

The definition of "executing an expression tree" is specific to a query provider. For example, it may involve translating the expression tree to a query language appropriate for an underlying data source.

The IQueryable(T) interface enables queries to be polymorphic. That is, because a query against an **IQueryable** data source is represented as an expression tree, it can be executed against different types of data sources.

The static (Shared in Visual Basic) methods defined in the class Queryable (except for AsQueryable, ThenBy, and ThenByDescending) extend objects of types that implement the IQueryable(T) interface.

For more information about how to create your own LINQ provider, see LINQ: Building an IQueryable Provider on MSDN Blogs.

#### .NET Framework

Supported in: 4.5.2, 4.5.1, 4.5, 4, 3.5#### .NET Framework Client Profile

Supported in: 4, 3.5 SP1#### Portable Class Library

Supported in: Portable Class Library#### .NET for Windows Store apps

Supported in: Windows 8#### .NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.