using namespace System; using namespace System::Reflection;

MethodBase::Invoke Method (Object, array<Object>)

.NET Framework 4

Other Versions

• .NET Framework 3.5
• .NET Framework 3.0
• .NET Framework 2.0
• Silverlight

Updated: October 2010

Invokes the method or constructor represented by the current instance, using the specified parameters.

Namespace:  System.Reflection
Assembly:  mscorlib (in mscorlib.dll)

Syntax

---

public:
virtual Object^ Invoke(
 Object^ obj, 
 array<Object^>^ parameters
) sealed

Parameters

obj

Type: System::Object The object on which to invoke the method or constructor. If a method is static, this argument is ignored. If a constructor is static, this argument must be nullptr or an instance of the class that defines the constructor.

parameters

Type: array<System::Object> An argument list for the invoked method or constructor. This is an array of objects with the same number, order, and type as the parameters of the method or constructor to be invoked. If there are no parameters, parameters should be nullptr. If the method or constructor represented by this instance takes a ref parameter (ByRef in Visual Basic), no special attribute is required for that parameter in order to invoke the method or constructor using this function. Any object in this array that is not explicitly initialized with a value will contain the default value for that object type. For reference-type elements, this value is nullptr. For value-type elements, this value is 0, 0.0, or false, depending on the specific element type.

Return Value

Type: System::Object
An object containing the return value of the invoked method, or nullptr in the case of a constructor.

Caution
Elements of the parameters array that represent parameters declared with the ref or out keyword may also be modified.

Implements

_MethodBase::Invoke(Object, array<Object>)

Exceptions

---

Exception	Condition
TargetException	The obj parameter is nullptr and the method is not static. -or- The method is not declared or inherited by the class of obj. -or- A static constructor is invoked, and obj is neither nullptr nor an instance of the class that declared the constructor.
ArgumentException	The elements of the parameters array do not match the signature of the method or constructor reflected by this instance.
TargetInvocationException	The invoked method or constructor throws an exception. -or- The current instance is a DynamicMethod that contains unverifiable code. See the "Verification" section in Remarks for DynamicMethod.
TargetParameterCountException	The parameters array does not have the correct number of arguments.
MethodAccessException	The caller does not have permission to execute the constructor.
InvalidOperationException	The type that declares the method is an open generic type. That is, the Type::ContainsGenericParameters property returns true for the declaring type.
NotSupportedException	The current instance is a MethodBuilder.

Remarks

---

This is a convenience method that calls the Invoke(Object, BindingFlags, Binder, array<Object>, CultureInfo) method overload, passing Default for invokeAttr and nullptr for binder and culture.
If the invoked method throws an exception, the Exception::GetBaseException method returns the exception.
To invoke a static method using its MethodInfo object, pass nullptr for obj.

Note
If this method overload is used to invoke an instance constructor, the object supplied for obj is reinitialized; that is, all instance initializers are executed. The return value is nullptr. If a class constructor is invoked, the class is reinitialized; that is, all class initializers are executed. The return value is nullptr.

Note

Starting with the .NET Framework version 2.0 Service Pack 1, this method can be used to access non-public members if the caller has been granted ReflectionPermission with the ReflectionPermissionFlag::RestrictedMemberAccess flag and if the grant set of the non-public members is restricted to the caller’s grant set, or a subset thereof. (See Security Considerations for Reflection.) To use this functionality, your application should target the .NET Framework version 3.5 or later.

If a parameter of the current method is a value type, and the corresponding argument in parameters is nullptr, the runtime passes a zero-initialized instance of the value type.

Examples

---

The following code example demonstrates dynamic method lookup using reflection. Note that you cannot use the MethodInfo object from the base class to invoke the overridden method in the derived class, because late binding cannot resolve overrides.

Copy

using namespace System;
using namespace System::Reflection;

public ref class MagicClass
{
private:
    int magicBaseValue;

public:
    MagicClass()
    {
        magicBaseValue = 9;
    }

    int ItsMagic(int preMagic)
    {
        return preMagic * magicBaseValue;
    }
};

public ref class TestMethodInfo
{
public:
    static void Main()
    {
        // Get the constructor and create an instance of MagicClass

        Type^ magicType = Type::GetType("MagicClass");
        ConstructorInfo^ magicConstructor = magicType->GetConstructor(Type::EmptyTypes);
        Object^ magicClassObject = magicConstructor->Invoke(gcnew array<Object^>(0));

        // Get the ItsMagic method and invoke with a parameter value of 100

        MethodInfo^ magicMethod = magicType->GetMethod("ItsMagic");
        Object^ magicValue = magicMethod->Invoke(magicClassObject, gcnew array<Object^>(1){100});

        Console::WriteLine("MethodInfo.Invoke() Example\n");
        Console::WriteLine("MagicClass.ItsMagic() returned: {0}", magicValue);
    }
};

int main()
{
    TestMethodInfo::Main();
}

// The example program gives the following output:
//
// MethodInfo.Invoke() Example
//
// MagicClass.ItsMagic() returned: 900