Queryable.Select<'TSource, 'TResult> Method (IQueryable<'TSource>, Expression<Func<'TSource, 'TResult>>)
Projects each element of a sequence into a new form.
Assembly: System.Core (in System.Core.dll)
static member Select<'TSource, 'TResult> : source:IQueryable<'TSource> * selector:Expression<Func<'TSource, 'TResult>> -> IQueryable<'TResult>
Parameters
- source
-
Type:
System.Linq.IQueryable<'TSource>
A sequence of values to project.
- selector
-
Type:
System.Linq.Expressions.Expression<Func<'TSource, 'TResult>>
A projection function to apply to each element.
Return Value
Type: System.Linq.IQueryable<'TResult>An IQueryable<'T> whose elements are the result of invoking a projection function on each element of source.
Type Parameters
- TSource
The type of the elements of source.
- TResult
The type of the value returned by the function represented by selector.
| Exception | Condition |
|---|---|
| ArgumentNullException | source or selector is null. |
This method has at least one parameter of type Expression<'TDelegate> whose type argument is one of the Func<'T, 'TResult> types. For these parameters, you can pass in a lambda expression and it will be compiled to an Expression<'TDelegate>.
The Select<'TSource, 'TResult>(IQueryable<'TSource>, Expression<Func<'TSource, 'TResult>>) method generates a MethodCallExpression that represents calling Select<'TSource, 'TResult>(IQueryable<'TSource>, Expression<Func<'TSource, 'TResult>>) itself as a constructed generic method. It then passes the MethodCallExpression to the CreateQuery(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.
The query behavior that occurs as a result of executing an expression tree that represents calling Select<'TSource, 'TResult>(IQueryable<'TSource>, Expression<Func<'TSource, 'TResult>>) depends on the implementation of the type of the source parameter. The expected behavior is that it invokes selector on each element of source to project it into a different form.
Available since 8
.NET Framework
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Windows Phone
Available since 8.1