Enumerable.First(TSource) Method (IEnumerable(TSource), Func(TSource, Boolean))
Silverlight
Returns the first element in a sequence that satisfies a specified condition.
Namespace: System.Linq
Assembly: System.Core (in System.Core.dll)
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Collections.Generic.IEnumerable(TSource)
An IEnumerable(T) to return an element from.
- predicate
- Type: System.Func(TSource, Boolean)
A function to test each element for a condition.
Return Value
Type: TSourceThe first element in the sequence that passes the test in the specified predicate function.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IEnumerable(TSource). When you use instance method syntax to call this method, omit the first parameter.| Exception | Condition |
|---|---|
| ArgumentNullException | source or predicate is a null reference (Nothing in Visual Basic). |
| InvalidOperationException | No element satisfies the condition in predicate. -or- The source sequence is empty. |
The First(TSource)(IEnumerable(TSource), Func(TSource, Boolean)) method throws an exception if no matching element is found in source. To instead return a default value when no matching element is found, use the FirstOrDefault method.
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.
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