Classes Class AutomationObject() :callMethod()

Method AutomationObject():callMethod() Foundation

Calls a method.

Syntax 
:callMethod( <cName> | <nID> [, <xParam, ...>] ) --> xValue
Parameters
<cName>
<cName> is the name of the method.
<nID>
<nID> is the numeric ID identifying the method to be called. The ID of a method can be queried by using :getIDsOfNames().
<xParam>
xParam is a comma-separated list of parameters that is passed to the method of the connected COM/ActiveX component.
Return

The data type of the result is defined by the method that is called. In case a method is called which is not known to the COM/ActiveX component, a runtime error occurs.

Description

:callMethod() is used to call a method of an ActiveX component.

Normally, :callMethod() need not be called directly by applications. Instead, COM/ActiveX methods can be called similar to a normal Xbase++ method. 

// Execute call via :callMethod() 
oAuto:callMethod( "Method", pram1, param2 )

is equivalent to 

// Execute method directly 
oAuto:Method( param1, param2 )

When methods are called, then Xbase++ data types are automatically converted to/from COM/ActiveX data types as needed.

Xbase++ - COM/ActiveX data types conversion.
Xbase++ COM/ActiveX Remark
A VT_ARRAY See Note below
M VT_BSTR
C VT_BSTR
C VT_I1 The length of the string is 1
C VT_UI1 The length of the string is 1
U VT_NULL
U VT_ERROR Omitted optional parameter
L VT_BOOL
D VT_DATE
O VT_DISPATCH Xbase++ object of class AutomationObject
N VT_INT
N VT_UINT
N VT_I2
N VT_UI2
N VT_I4
N VT_UI4
N VT_I8
N VT_UI8
N VT_R4
N VT_R8
N VT_CY
N VT_DECIMAL
ANY VT_VARIANT

When the COM/ActiveX component does not provide information about what type is to be used in a method call or as a property value then conversion is done according following table:

Xbase++ COM/ActiveX
A VT_ARRAY
C VT_BSTR
U VT_NULL
L VT_BOOL
D VT_DATE
O VT_DISPATCH
N VT_I4 *)
N VT_R8 *)
  1. Depending on the precision of the numeric value.

COM/ActiveX cannot handle arrays where the array elements are of different types. In this case, the type of the first array element is considered when it comes to type conversion.

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