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Expression.Call Method (Expression, MethodInfo)

Creates a MethodCallExpression that represents a call to an instance method that takes no arguments.

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

public static MethodCallExpression Call(
	Expression instance,
	MethodInfo method
)

Parameters

instance
Type: System.Linq.Expressions.Expression
An Expression that specifies the instance for an instance method call (pass null for a static (Shared in Visual Basic) method).
method
Type: System.Reflection.MethodInfo
A MethodInfo to set the Method property equal to.

Return Value

Type: System.Linq.Expressions.MethodCallExpression
A MethodCallExpression that has the NodeType property equal to Call and the Object and Method properties set to the specified values.

ExceptionCondition
ArgumentNullException

method is null.

-or-

instance is null and method represents an instance method.

ArgumentException

instance.Type is not assignable to the declaring type of the method represented by method.

To represent a call to a static (Shared in Visual Basic) method, pass in null for the instance parameter when you call this method.

If method represents an instance method, the Type property of instance must be assignable to the declaring type of the method represented by method.

The Arguments property of the resulting MethodCallExpression is empty. The Type property is equal to the return type of the method represented by method.

The following code example shows how to create an expression that calls a method without arguments.


            // Add the following directive to your file:
            // using System.Linq.Expressions;  

            // This expression represents a call to an instance method without arguments.
            Expression callExpr = Expression.Call(
                Expression.Constant("sample string"), typeof(String).GetMethod("ToUpper", new Type[] { }));

            // Print out the expression.
            Console.WriteLine(callExpr.ToString());

            // The following statement first creates an expression tree,
            // then compiles it, and then executes it.  
            Console.WriteLine(Expression.Lambda<Func<String>>(callExpr).Compile()());

            // This code example produces the following output:
            //
            // "sample string".ToUpper
            // SAMPLE STRING



.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

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.
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