Queryable.First<TSource> Method (IQueryable<TSource>, Expression<Func<TSource, Boolean>>)
Returns the first element of a sequence that satisfies a specified condition.
Assembly: System.Core (in System.Core.dll)
public static TSource First<TSource>( this IQueryable<TSource> source, Expression<Func<TSource, bool>> predicate )
The first element in source that passes the test in predicate.
The type of the elements of source.
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 MethodCallExpression that represents calling itself as a constructed generic method. It then passes the MethodCallExpression to the Execute<TResult>(Expression) method of the IQueryProvider represented by the Provider property of the source parameter.method generates a
The query behavior that occurs as a result of executing an expression tree that represents callingdepends on the implementation of the type of the source parameter. The expected behavior is that it returns the first element in source that satisfies the condition specified by predicate.
The following code example demonstrates how to useto return the first element of a sequence that satisfies a condition.
Available since 8
Available since 3.5
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.1
Available since 8.1