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Queryable Class
.NET Framework Class Library
Queryable Class

Provides a set of static (Shared in Visual Basic) methods for querying data structures that implement IQueryable<(Of <(T>)>).

Inheritance Hierarchy
System..::.Object
  System.Linq..::.Queryable

Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Syntax 
<ExtensionAttribute> _
Public NotInheritable Class Queryable
public static class Queryable
[ExtensionAttribute]
public ref class Queryable abstract sealed
[<AbstractClass>]
[<Sealed>]
type Queryable =  class end

The Queryable type exposes the following members.

Methods
 NameDescription
Public methodStatic memberSupported by Portable Class LibraryAggregate<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TSource, TSource>)>)>)>))Applies an accumulator function over a sequence.
Public methodStatic memberSupported by Portable Class LibraryAggregate<(Of <(TSource, TAccumulate>)>)(IQueryable<(Of <(TSource>)>), TAccumulate, Expression<(Of <(Func<(Of <(TAccumulate, TSource, TAccumulate>)>)>)>))Applies an accumulator function over a sequence. The specified seed value is used as the initial accumulator value.
Public methodStatic memberSupported by Portable Class LibraryAggregate<(Of <(TSource, TAccumulate, TResult>)>)(IQueryable<(Of <(TSource>)>), TAccumulate, Expression<(Of <(Func<(Of <(TAccumulate, TSource, TAccumulate>)>)>)>), Expression<(Of <(Func<(Of <(TAccumulate, TResult>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAll<(Of <(TSource>)>)Determines whether all the elements of a sequence satisfy a condition.
Public methodStatic memberSupported by Portable Class LibraryAny<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Determines whether a sequence contains any elements.
Public methodStatic memberSupported by Portable Class LibraryAny<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Determines whether any element of a sequence satisfies a condition.
Public methodStatic memberSupported by Portable Class LibraryAsQueryable(IEnumerable)Converts an IEnumerable to an IQueryable.
Public methodStatic memberSupported by Portable Class LibraryAsQueryable<(Of <(TElement>)>)(IEnumerable<(Of <(TElement>)>))Converts a generic IEnumerable<(Of <(T>)>) to a generic IQueryable<(Of <(T>)>).
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Decimal>)>))Computes the average of a sequence of Decimal values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Nullable<(Of <(Decimal>)>)>)>))Computes the average of a sequence of nullable Decimal values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Double>)>))Computes the average of a sequence of Double values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Nullable<(Of <(Double>)>)>)>))Computes the average of a sequence of nullable Double values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Int32>)>))Computes the average of a sequence of Int32 values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Nullable<(Of <(Int32>)>)>)>))Computes the average of a sequence of nullable Int32 values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Int64>)>))Computes the average of a sequence of Int64 values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Nullable<(Of <(Int64>)>)>)>))Computes the average of a sequence of nullable Int64 values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Nullable<(Of <(Single>)>)>)>))Computes the average of a sequence of nullable Single values.
Public methodStatic memberSupported by Portable Class LibraryAverage(IQueryable<(Of <(Single>)>))Computes the average of a sequence of Single values.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Decimal>)>)>)>))Computes the average of a sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Double>)>)>)>))Computes the average of a sequence of Double values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32>)>)>)>))Computes the average of a sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int64>)>)>)>))Computes the average of a sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Decimal>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Double>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Int32>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Int64>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Single>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryAverage<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Single>)>)>)>))Computes the average of a sequence of Single values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryCast<(Of <(TResult>)>)Converts the elements of an IQueryable to the specified type.
Public methodStatic memberSupported by Portable Class LibraryConcat<(Of <(TSource>)>)Concatenates two sequences.
Public methodStatic memberSupported by Portable Class LibraryContains<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), TSource)Determines whether a sequence contains a specified element by using the default equality comparer.
Public methodStatic memberSupported by Portable Class LibraryContains<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), TSource, IEqualityComparer<(Of <(TSource>)>))Determines whether a sequence contains a specified element by using a specified IEqualityComparer<(Of <(T>)>).
Public methodStatic memberSupported by Portable Class LibraryCount<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the number of elements in a sequence.
Public methodStatic memberSupported by Portable Class LibraryCount<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the number of elements in the specified sequence that satisfies a condition.
Public methodStatic memberSupported by Portable Class LibraryDefaultIfEmpty<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the elements of the specified sequence or the type parameter's default value in a singleton collection if the sequence is empty.
Public methodStatic memberSupported by Portable Class LibraryDefaultIfEmpty<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), TSource)Returns the elements of the specified sequence or the specified value in a singleton collection if the sequence is empty.
Public methodStatic memberSupported by Portable Class LibraryDistinct<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns distinct elements from a sequence by using the default equality comparer to compare values.
Public methodStatic memberSupported by Portable Class LibraryDistinct<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEqualityComparer<(Of <(TSource>)>))Returns distinct elements from a sequence by using a specified IEqualityComparer<(Of <(T>)>) to compare values.
Public methodStatic memberSupported by Portable Class LibraryElementAt<(Of <(TSource>)>)Returns the element at a specified index in a sequence.
Public methodStatic memberSupported by Portable Class LibraryElementAtOrDefault<(Of <(TSource>)>)Returns the element at a specified index in a sequence or a default value if the index is out of range.
Public methodStatic memberSupported by Portable Class LibraryExcept<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>))Produces the set difference of two sequences by using the default equality comparer to compare values.
Public methodStatic memberSupported by Portable Class LibraryExcept<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>), IEqualityComparer<(Of <(TSource>)>))Produces the set difference of two sequences by using the specified IEqualityComparer<(Of <(T>)>) to compare values.
Public methodStatic memberSupported by Portable Class LibraryFirst<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the first element of a sequence.
Public methodStatic memberSupported by Portable Class LibraryFirst<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the first element of a sequence that satisfies a specified condition.
Public methodStatic memberSupported by Portable Class LibraryFirstOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the first element of a sequence, or a default value if the sequence contains no elements.
Public methodStatic memberSupported by Portable Class LibraryFirstOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the first element of a sequence that satisfies a specified condition or a default value if no such element is found.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>))Groups the elements of a sequence according to a specified key selector function.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), IEqualityComparer<(Of <(TKey>)>))Groups the elements of a sequence according to a specified key selector function and compares the keys by using a specified comparer.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TElement>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TElement>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TKey, IEnumerable<(Of <(TSource>)>), TResult>)>)>)>))Groups the elements of a sequence according to a specified key selector function and creates a result value from each group and its key.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TElement>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TElement>)>)>)>), IEqualityComparer<(Of <(TKey>)>))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.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TKey, IEnumerable<(Of <(TSource>)>), TResult>)>)>)>), IEqualityComparer<(Of <(TKey>)>))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.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TElement, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TElement>)>)>)>), Expression<(Of <(Func<(Of <(TKey, IEnumerable<(Of <(TElement>)>), TResult>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryGroupBy<(Of <(TSource, TKey, TElement, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TElement>)>)>)>), Expression<(Of <(Func<(Of <(TKey, IEnumerable<(Of <(TElement>)>), TResult>)>)>)>), IEqualityComparer<(Of <(TKey>)>))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.
Public methodStatic memberSupported by Portable Class LibraryGroupJoin<(Of <(TOuter, TInner, TKey, TResult>)>)(IQueryable<(Of <(TOuter>)>), IEnumerable<(Of <(TInner>)>), Expression<(Of <(Func<(Of <(TOuter, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TInner, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TOuter, IEnumerable<(Of <(TInner>)>), TResult>)>)>)>))Correlates the elements of two sequences based on key equality and groups the results. The default equality comparer is used to compare keys.
Public methodStatic memberSupported by Portable Class LibraryGroupJoin<(Of <(TOuter, TInner, TKey, TResult>)>)(IQueryable<(Of <(TOuter>)>), IEnumerable<(Of <(TInner>)>), Expression<(Of <(Func<(Of <(TOuter, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TInner, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TOuter, IEnumerable<(Of <(TInner>)>), TResult>)>)>)>), IEqualityComparer<(Of <(TKey>)>))Correlates the elements of two sequences based on key equality and groups the results. A specified IEqualityComparer<(Of <(T>)>) is used to compare keys.
Public methodStatic memberSupported by Portable Class LibraryIntersect<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>))Produces the set intersection of two sequences by using the default equality comparer to compare values.
Public methodStatic memberSupported by Portable Class LibraryIntersect<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>), IEqualityComparer<(Of <(TSource>)>))Produces the set intersection of two sequences by using the specified IEqualityComparer<(Of <(T>)>) to compare values.
Public methodStatic memberSupported by Portable Class LibraryJoin<(Of <(TOuter, TInner, TKey, TResult>)>)(IQueryable<(Of <(TOuter>)>), IEnumerable<(Of <(TInner>)>), Expression<(Of <(Func<(Of <(TOuter, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TInner, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TOuter, TInner, TResult>)>)>)>))Correlates the elements of two sequences based on matching keys. The default equality comparer is used to compare keys.
Public methodStatic memberSupported by Portable Class LibraryJoin<(Of <(TOuter, TInner, TKey, TResult>)>)(IQueryable<(Of <(TOuter>)>), IEnumerable<(Of <(TInner>)>), Expression<(Of <(Func<(Of <(TOuter, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TInner, TKey>)>)>)>), Expression<(Of <(Func<(Of <(TOuter, TInner, TResult>)>)>)>), IEqualityComparer<(Of <(TKey>)>))Correlates the elements of two sequences based on matching keys. A specified IEqualityComparer<(Of <(T>)>) is used to compare keys.
Public methodStatic memberSupported by Portable Class LibraryLast<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the last element in a sequence.
Public methodStatic memberSupported by Portable Class LibraryLast<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the last element of a sequence that satisfies a specified condition.
Public methodStatic memberSupported by Portable Class LibraryLastOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the last element in a sequence, or a default value if the sequence contains no elements.
Public methodStatic memberSupported by Portable Class LibraryLastOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the last element of a sequence that satisfies a condition or a default value if no such element is found.
Public methodStatic memberSupported by Portable Class LibraryLongCount<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns an Int64 that represents the total number of elements in a sequence.
Public methodStatic memberSupported by Portable Class LibraryLongCount<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns an Int64 that represents the number of elements in a sequence that satisfy a condition.
Public methodStatic memberSupported by Portable Class LibraryMax<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the maximum value in a generic IQueryable<(Of <(T>)>).
Public methodStatic memberSupported by Portable Class LibraryMax<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TResult>)>)>)>))Invokes a projection function on each element of a generic IQueryable<(Of <(T>)>) and returns the maximum resulting value.
Public methodStatic memberSupported by Portable Class LibraryMin<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the minimum value of a generic IQueryable<(Of <(T>)>).
Public methodStatic memberSupported by Portable Class LibraryMin<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TResult>)>)>)>))Invokes a projection function on each element of a generic IQueryable<(Of <(T>)>) and returns the minimum resulting value.
Public methodStatic memberSupported by Portable Class LibraryOfType<(Of <(TResult>)>)Filters the elements of an IQueryable based on a specified type.
Public methodStatic memberSupported by Portable Class LibraryOrderBy<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>))Sorts the elements of a sequence in ascending order according to a key.
Public methodStatic memberSupported by Portable Class LibraryOrderBy<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), IComparer<(Of <(TKey>)>))Sorts the elements of a sequence in ascending order by using a specified comparer.
Public methodStatic memberSupported by Portable Class LibraryOrderByDescending<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>))Sorts the elements of a sequence in descending order according to a key.
Public methodStatic memberSupported by Portable Class LibraryOrderByDescending<(Of <(TSource, TKey>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), IComparer<(Of <(TKey>)>))Sorts the elements of a sequence in descending order by using a specified comparer.
Public methodStatic memberSupported by Portable Class LibraryReverse<(Of <(TSource>)>)Inverts the order of the elements in a sequence.
Public methodStatic memberSupported by Portable Class LibrarySelect<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TResult>)>)>)>))Projects each element of a sequence into a new form.
Public methodStatic memberSupported by Portable Class LibrarySelect<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, TResult>)>)>)>))Projects each element of a sequence into a new form by incorporating the element's index.
Public methodStatic memberSupported by Portable Class LibrarySelectMany<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, IEnumerable<(Of <(TResult>)>)>)>)>)>))Projects each element of a sequence to an IEnumerable<(Of <(T>)>) and combines the resulting sequences into one sequence.
Public methodStatic memberSupported by Portable Class LibrarySelectMany<(Of <(TSource, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, IEnumerable<(Of <(TResult>)>)>)>)>)>))Projects each element of a sequence to an IEnumerable<(Of <(T>)>) and combines the resulting sequences into one sequence. The index of each source element is used in the projected form of that element.
Public methodStatic memberSupported by Portable Class LibrarySelectMany<(Of <(TSource, TCollection, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, IEnumerable<(Of <(TCollection>)>)>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TCollection, TResult>)>)>)>))Projects each element of a sequence to an IEnumerable<(Of <(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.
Public methodStatic memberSupported by Portable Class LibrarySelectMany<(Of <(TSource, TCollection, TResult>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, IEnumerable<(Of <(TCollection>)>)>)>)>)>), Expression<(Of <(Func<(Of <(TSource, TCollection, TResult>)>)>)>))Projects each element of a sequence to an IEnumerable<(Of <(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.
Public methodStatic memberSupported by Portable Class LibrarySequenceEqual<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>))Determines whether two sequences are equal by using the default equality comparer to compare elements.
Public methodStatic memberSupported by Portable Class LibrarySequenceEqual<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>), IEqualityComparer<(Of <(TSource>)>))Determines whether two sequences are equal by using a specified IEqualityComparer<(Of <(T>)>) to compare elements.
Public methodStatic memberSupported by Portable Class LibrarySingle<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))Returns the only element of a sequence, and throws an exception if there is not exactly one element in the sequence.
Public methodStatic memberSupported by Portable Class LibrarySingle<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns the only element of a sequence that satisfies a specified condition, and throws an exception if more than one such element exists.
Public methodStatic memberSupported by Portable Class LibrarySingleOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySingleOrDefault<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySkip<(Of <(TSource>)>)Bypasses a specified number of elements in a sequence and then returns the remaining elements.
Public methodStatic memberSupported by Portable Class LibrarySkipWhile<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Bypasses elements in a sequence as long as a specified condition is true and then returns the remaining elements.
Public methodStatic memberSupported by Portable Class LibrarySkipWhile<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, Boolean>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Decimal>)>))Computes the sum of a sequence of Decimal values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Nullable<(Of <(Decimal>)>)>)>))Computes the sum of a sequence of nullable Decimal values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Double>)>))Computes the sum of a sequence of Double values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Nullable<(Of <(Double>)>)>)>))Computes the sum of a sequence of nullable Double values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Int32>)>))Computes the sum of a sequence of Int32 values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Nullable<(Of <(Int32>)>)>)>))Computes the sum of a sequence of nullable Int32 values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Int64>)>))Computes the sum of a sequence of Int64 values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Nullable<(Of <(Int64>)>)>)>))Computes the sum of a sequence of nullable Int64 values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Nullable<(Of <(Single>)>)>)>))Computes the sum of a sequence of nullable Single values.
Public methodStatic memberSupported by Portable Class LibrarySum(IQueryable<(Of <(Single>)>))Computes the sum of a sequence of Single values.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Decimal>)>)>)>))Computes the sum of the sequence of Decimal values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Double>)>)>)>))Computes the sum of the sequence of Double values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32>)>)>)>))Computes the sum of the sequence of Int32 values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int64>)>)>)>))Computes the sum of the sequence of Int64 values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Decimal>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Double>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Int32>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Int64>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Nullable<(Of <(Single>)>)>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibrarySum<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Single>)>)>)>))Computes the sum of the sequence of Single values that is obtained by invoking a projection function on each element of the input sequence.
Public methodStatic memberSupported by Portable Class LibraryTake<(Of <(TSource>)>)Returns a specified number of contiguous elements from the start of a sequence.
Public methodStatic memberSupported by Portable Class LibraryTakeWhile<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Returns elements from a sequence as long as a specified condition is true.
Public methodStatic memberSupported by Portable Class LibraryTakeWhile<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, Boolean>)>)>)>))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.
Public methodStatic memberSupported by Portable Class LibraryThenBy<(Of <(TSource, TKey>)>)(IOrderedQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>))Performs a subsequent ordering of the elements in a sequence in ascending order according to a key.
Public methodStatic memberSupported by Portable Class LibraryThenBy<(Of <(TSource, TKey>)>)(IOrderedQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), IComparer<(Of <(TKey>)>))Performs a subsequent ordering of the elements in a sequence in ascending order by using a specified comparer.
Public methodStatic memberSupported by Portable Class LibraryThenByDescending<(Of <(TSource, TKey>)>)(IOrderedQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>))Performs a subsequent ordering of the elements in a sequence in descending order, according to a key.
Public methodStatic memberSupported by Portable Class LibraryThenByDescending<(Of <(TSource, TKey>)>)(IOrderedQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, TKey>)>)>)>), IComparer<(Of <(TKey>)>))Performs a subsequent ordering of the elements in a sequence in descending order by using a specified comparer.
Public methodStatic memberSupported by Portable Class LibraryUnion<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>))Produces the set union of two sequences by using the default equality comparer.
Public methodStatic memberSupported by Portable Class LibraryUnion<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), IEnumerable<(Of <(TSource>)>), IEqualityComparer<(Of <(TSource>)>))Produces the set union of two sequences by using a specified IEqualityComparer<(Of <(T>)>).
Public methodStatic memberSupported by Portable Class LibraryWhere<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Boolean>)>)>)>))Filters a sequence of values based on a predicate.
Public methodStatic memberSupported by Portable Class LibraryWhere<(Of <(TSource>)>)(IQueryable<(Of <(TSource>)>), Expression<(Of <(Func<(Of <(TSource, Int32, Boolean>)>)>)>))Filters a sequence of values based on a predicate. Each element's index is used in the logic of the predicate function.
Public methodStatic memberSupported by Portable Class LibraryZip<(Of <(TFirst, TSecond, TResult>)>)Merges two sequences by using the specified predicate function.
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Remarks

The set of methods declared in the Queryable class provides an implementation of the standard query operators for querying data sources that implement IQueryable<(Of <(T>)>). The standard query operators are general purpose methods that follow the LINQ pattern and enable you to express traversal, filter, and projection operations over data in any .NET-based programming language.

The majority of the methods in this class are defined as extension methods that extend the IQueryable<(Of <(T>)>) type. This means they can be called like an instance method on any object that implements IQueryable<(Of <(T>)>). These methods that extend IQueryable<(Of <(T>)>) do not perform any querying directly. Instead, their functionality is to build an Expression object, which is an expression tree that represents the cumulative query. The methods then pass the new expression tree to either the Execute<(Of <(TResult>)>)(Expression) method or the CreateQuery<(Of <(TElement>)>)(Expression) method of the input IQueryable<(Of <(T>)>). The method that is called depends on whether the Queryable method returns a singleton value, in which case Execute<(Of <(TResult>)>)(Expression) is called, or has enumerable results, in which case CreateQuery<(Of <(TElement>)>)(Expression) is called.

The actual query execution on the target data is performed by a class that implements IQueryable<(Of <(T>)>). The expectation of any IQueryable<(Of <(T>)>) implementation is that the result of executing an expression tree that was constructed by a Queryable standard query operator method is equivalent to the result of calling the corresponding method in the Enumerable class, if the data source were an IEnumerable<(Of <(T>)>).

In addition to the standard query operator methods that operate on IQueryable<(Of <(T>)>) objects, this class also contains a method, AsQueryable, which types IEnumerable objects as IQueryable objects.

Version Information

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
Thread Safety
Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
See Also

Reference

System.Linq Namespace

Other Resources

LINQ (Language-Integrated Query)
Standard Query Operators Overview
Expression Trees (C# and Visual Basic)
LINQ to SQL
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