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OpCodes.Isinst Field

Tests whether an object reference (type O) is an instance of a particular class.

[Visual Basic]
Public Shared ReadOnly Isinst As OpCode
[C#]
public static readonly OpCode Isinst;
[C++]
public: static OpCode Isinst;
[JScript]
public static var Isinst : OpCode;

Remarks

The following table lists the instruction's hexadecimal and Microsoft Intermediate Language (MSIL) assembly format, along with a brief reference summary:

Format Assembly Format Description
75 < T > isinst class Tests if an object reference is an instance of class, returning either a null reference or an instance of that class or interface.

The stack transitional behavior, in sequential order, is:

  1. An object reference is pushed onto the stack.
  2. The object reference is popped from the stack and tested to see if it is an instance of the class passed in class.
  3. The result (either an object reference or a null reference) is pushed onto the stack.

Class is a metadata token indicating the desired class. If the class of the object on the top of the stack implements class (if class is an interface) or is a derived class of class (if class is a regular class) then it is cast to type class and the result is pushed on the stack, exactly as though Castclass had been called. Otherwise, a null reference is pushed on the stack. If the object reference itself is a null reference, then isinst likewise returns a null reference.

TypeLoadException is thrown if class cannot be found. This is typically detected when the Microsoft Intermediate Language (MSIL) instructions are converted to native code rather than at runtime.

The following Emit constructor overload can use the isinst opcode:

  • ILGenerator.Emit(OpCode, Type)

Requirements

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family

See Also

OpCodes Class | OpCodes Members | System.Reflection.Emit Namespace

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