Determines whether all the elements of a sequence satisfy a condition.
Assemblies: System.Linq.Queryable (in System.Linq.Queryable.dll)
System.Core (in System.Core.dll)
static member All : source:IQueryable<'TSource> * predicate:Expression<Func<'TSource, bool>> -> bool
The type of the elements of source.
- Type: System.Linq.IQueryable()
A sequence whose elements to test for a condition.
Return ValueType: 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.
Usage NoteIn Visual Basic and C#, you can call this method as an instance method on any object of type IQueryable(). 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).
source or predicate is a null reference (Nothing in Visual Basic).
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 method generates a MethodCallExpression that represents calling 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 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 to determine whether all the elements in a sequence satisfy a condition.
The Boolean value that the 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.