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Enumerable::First<TSource> Method (IEnumerable<TSource>^, Func<TSource, Boolean>^)
.NET Framework (current version)
Returns the first element in a sequence that satisfies a specified condition.
Assembly: System.Core (in System.Core.dll)
public: generic<typename TSource> [ExtensionAttribute] static TSource First( IEnumerable<TSource>^ source, Func<TSource, bool>^ predicate )
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.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| ArgumentNullException | source or predicate is null. |
| 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<TSource> method.
Universal Windows Platform
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 7.0
Windows Phone
Available since 8.1
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 7.0
Windows Phone
Available since 8.1
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