Stelem_Ref Field
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OpCodes.Stelem_Ref Field

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Replaces the array element at a given index with the object ref value (type O) on the evaluation stack.

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

public static readonly OpCode Stelem_Ref

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


Assembly Format




Replaces an array element at the supplied index with the ref value (type O) on the stack.

The stack transitional behavior, in sequential order, is:

  1. An object reference to an array, array, is pushed onto the stack.

  2. A valid index to an element in array is pushed onto the stack.

  3. A value is pushed onto the stack.

  4. The value, the index, and the array reference are popped from the stack; the value is put into the array element at the given index.

The stelem.ref instruction replaces the value of the element at the supplied index in the one-dimensional array array with the ref (type O) value pushed onto the stack.

Arrays are objects and hence represented by a value of type O. The index is type native int.

Note that stelem.ref implicitly casts the supplied value to the element type of array before assigning the value to the array element. This cast can fail, even for verified code. Thus the stelem.ref instruction can throw InvalidCastException. For one-dimensional arrays that aren't zero-based and for multidimensional arrays, the Array class provides a SetValue method.

NullReferenceException is thrown if array is a null reference.

IndexOutOfRangeException is thrown if index is negative, or larger than the bound of array.

ArrayTypeMismatchException is thrown if array does not hold elements of the required type.

The following Emit method overload can use the stelem.ref opcode:

  • ILGenerator.Emit(OpCode)

Windows Phone OS

Supported in: 8.1, 8.0, 7.1

Windows Phone

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