Queryable::All<TSource> Method
Determines whether all the elements of a sequence satisfy a condition.
Assembly: System.Core (in System.Core.dll)
[ExtensionAttribute] public: generic<typename TSource> static bool All( IQueryable<TSource>^ source, Expression<Func<TSource, bool>^>^ predicate )
Type Parameters
- TSource
The type of the elements of source.
Parameters
- source
- Type: System.Linq::IQueryable<TSource>
A sequence whose elements to test for a condition.
- predicate
- Type: System.Linq.Expressions::Expression<Func<TSource, Boolean>>
A function to test each element for a condition.
Return Value
Type: System::Booleantrue if every element of the source sequence passes the test in the specified predicate, or if the sequence is empty; otherwise, false.
Usage Note
In Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable<TSource>. When you use instance method syntax to call this method, omit the first parameter. For more information, see Extension Methods (Visual Basic) or Extension Methods (C# Programming Guide).| Exception | Condition |
|---|---|
| ArgumentNullException | source or predicate is nullptr. |
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 All<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) method generates a MethodCallExpression that represents calling All<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) 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.
The query behavior that occurs as a result of executing an expression tree that represents calling All<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) depends on the implementation of the source parameter's type. The expected behavior is that it determines if all the elements in source satisfy the condition in predicate.
The following code example demonstrates how to use All<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) to determine whether all the elements in a sequence satisfy a condition.
The Boolean value that the All<TSource>(IQueryable<TSource>, Expression<Func<TSource, Boolean>>) method returns is typically used in the predicate of a where clause (Where clause in Visual Basic) or a direct call to the Where method. The following example demonstrates this use of the All method.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.