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Enumerable.All<'TSource> Method (IEnumerable<'TSource>, Func<'TSource, Boolean>)

 

Determines whether all elements of a sequence satisfy a condition.

Namespace:   System.Linq
Assembly:  System.Core (in System.Core.dll)

static member All<'TSource> : 
        source:IEnumerable<'TSource> *
        predicate:Func<'TSource, bool> -> bool

Parameters

source
Type: System.Collections.Generic.IEnumerable<'TSource>

An IEnumerable<'T> that contains the elements to apply the predicate to.

predicate
Type: System.Func<'TSource, Boolean>

A function to test each element for a condition.

Return Value

Type: System.Boolean

true if every element of the source sequence passes the test in the specified predicate, or if the sequence is empty; otherwise, false.

Type Parameters

TSource

The type of the elements of source.

Exception Condition
ArgumentNullException

source or predicate is null.

System_CAPS_noteNote

This method does not return all the elements of a collection. Instead, it determines whether all the elements of a collection satisfy a condition.

The enumeration of source is stopped as soon as the result can be determined.

In Visual Basic query expression syntax, an Aggregate Into All() clause translates to an invocation of All<'TSource>.

The following code example demonstrates how to use All<'TSource> to determine whether all the elements in a sequence satisfy a condition. Variable allStartWithB is true if all the pet names start with "B" or if the pets array is empty.

No code example is currently available or this language may not be supported.

The Boolean value that the All<'TSource> method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where<'TSource> method. The following example demonstrates this use of the All method.

No code example is currently available or this language may not be supported.

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
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