OpCodes.Castclass Field
Microsoft Silverlight will reach end of support after October 2021. Learn more.
Attempts to cast an object passed by reference to the specified class.
Namespace: System.Reflection.Emit
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
<ComVisibleAttribute(True)> _
Public Shared ReadOnly Castclass As OpCode
[ComVisibleAttribute(true)]
public static readonly OpCode Castclass
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 |
|---|---|---|
74 < T > |
castclass class |
Casts an object to a new object of type class. |
The stack transitional behavior, in sequential order, is:
An object reference is pushed onto the stack.
The object reference is popped from the stack; the referenced object is cast as the specified class.
If successful, a new object reference is pushed onto the stack.
The castclass instruction attempts to cast the object reference (type O) atop the stack to a specified class. The new class is specified by a metadata token indicating the desired class. If the class of the object on the top of the stack does not implement the new class (assuming the new class is an interface) and is not a derived class of the new class then an InvalidCastException is thrown. If the object reference is a null reference, castclass succeeds and returns the new object as a null reference.
InvalidCastException is thrown if obj cannot be cast to class.
TypeLoadException is thrown if class cannot be found. This is typically detected when MSIL instructions are converted to native code, not at run time.
The following Emit method overload can use the castclass opcode:
- ILGenerator.Emit(OpCode, Type)
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.