SetMethodInfo Method 556

Description

This method is used to redefine the arguments or data types associated with a method that is exported by a COM object. SetMethodInfo is used to override the information provided by the object's Type Library.

The argument to SetMethodInfo is a 2 or 3-element array as follows:

`[1]`	Method name	character vector
`[2]`	Method info	nested vector (see below)
`[3]`	Method index	integer

If you wish to describe the method completely, the structure of Method info should be identical to the structure returned by GetMethodInfo, although abbreviated formats are also allowed.

If the object exports the method directly, and not through the standard IDispatch interface, you must also specify Method Index, which is the index of the method in the object's virtual table (vtable). This information may be available in printed documentation or in a C-language header file.

For example, the InchesToPoint method exported by Excel.Application takes a single argument whose name is Arg1 and whose data type is VT_R8. The function returns a result of the same data type. The details provided in the Excel.Application Type Library are in fact correct, but if you wanted to redefine them, the following statements could be used to describe the InchesToPoints method.

      'EX' ⎕WC 'OLEClient' 'Excel.Application' ('AutoBrowse' 0)

      methodinfo← ('' 'VT_R8')('Arg1' 'VT_R8')
      EX.SetMethodInfo 'InchesToPoints' methodinfo

Note that the structure of variable methodinfo is identical to the result of the GetMethodInfo method.

      DISPLAY methodinfo
┌→───────────────────────────────────┐
│ ┌→────────────┐ ┌→───────────────┐ │
│ │ ┌⊖┐ ┌→────┐ │ │ ┌→───┐ ┌→────┐ │ │
│ │ │ │ │VT_R8│ │ │ │Arg1│ │VT_R8│ │ │
│ │ └─┘ └─────┘ │ │ └────┘ └─────┘ │ │
│ └∊────────────┘ └∊───────────────┘ │
└∊───────────────────────────────────┘

      DISPLAY EX.GetMethodInfo 'InchesToPoints'
┌→───────────────────────────────────┐
│ ┌→────────────┐ ┌→───────────────┐ │
│ │ ┌⊖┐ ┌→────┐ │ │ ┌→───┐ ┌→────┐ │ │
│ │ │ │ │VT_R8│ │ │ │Arg1│ │VT_R8│ │ │
│ │ └─┘ └─────┘ │ │ └────┘ └─────┘ │ │
│ └∊────────────┘ └∊───────────────┘ │
└∊───────────────────────────────────┘

Unless you are going to call the method using the names of its arguments, these names are clearly superfluous and may be omitted, for example:

      methodinfo← 'VT_R8' 'VT_R8'
      EX.SetMethodInfo 'InchesToPoints' methodinfo