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Enumerable.First<TSource> Method (IEnumerable<TSource>)
.NET Framework (current version)
Returns the first element of a sequence.
Assembly: System.Core (in System.Core.dll)
Parameters
- source
-
Type:
System.Collections.Generic.IEnumerable<TSource>
The IEnumerable<T> to return the first element of.
Return Value
Type: TSourceThe first element in the specified sequence.
Type Parameters
- TSource
The type of the elements of source.
| Exception | Condition |
|---|---|
| ArgumentNullException | source is null. |
| InvalidOperationException | The source sequence is empty. |
The First<TSource>(IEnumerable<TSource>) method throws an exception if source contains no elements. To instead return a default value when the source sequence is empty, use the FirstOrDefault<TSource> method.
The following code example demonstrates how to use First<TSource>(IEnumerable<TSource>) to return the first element of an array.
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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