wpclsEnumClipboardClasses
This class method enumerates through all the object classes that a particular rendering mechanism supports.
Syntax
_wpclsEnumClipboardClasses(somSelf, aCBFormat, aPrevious)
Parameters
- somSelf (M_WPDataFile *) - input
- Pointer to the WPDataFile class object.
- aCBFormat (ULONG) - input
- Atom referring to the clipboard format.
- aPrevious (ULONG) - input
- The last atom passed in or 0 to start from the beginning.
Returns
- rv (ULONG) - returns
- An atom referring to a class name, or 0 if finished.
Remarks
If the second parameter is zero, this method returns the first atom in the list. Otherwise, it returns the next class name after the one passed in. If the atom passed in is the last atom in the list, the method will return 0.
The class names are returned and passed as atoms. Use WinQueryAtomName to get the real name from the atom.
How to Override
This method is not generally overridden.
Usage
This method can be called in a loop to enumerate all of the object classes that can process a specified clipboard format.
Example Code
Declaration.
#define INCL_WINWORKPLACE #include <os2.png> M_WPDataFile *somSelf; /* Pointer to the WPDataFile class object. */ ULONG aCBFormat; /* Atom referring to the clipboard format. */ ULONG aPrevious; /* The last atom passed in or 0 to start from the beginning. */ ULONG rv; /* An atom referring to a class name, or 0 if finished. */ rv = _wpclsEnumClipboardClasses(somSelf, aCBFormat, aPrevious);
This example enumerates all of the object classes that process the "MyFormat" clipboard format.
HATOMTBL hAtomTable = NULLHANDLE;
ATOM aFormat = 0, aClass = 0;
CHAR szClassName[CCHMAXSTRING];
/* Find the system atom table */
hAtomTable = WinQuerySystemAtomTable();
if (hAtomTable)
{
/* Add an atom to the system atom table for the clipboard format */
aFormat = WinAddAtom(hAtomTable, "MyFormat");
if (aFormat)
{
/* Enumerate the object classes that process the specified
* clipboard format */
aClass = _wpclsEnumClipboardClasses(aFormat, (ATOM)0);
while (aClass)
{
if (WinQueryAtomName(hAtomTable,
aFormat,
szClassName,
sizeof(szClassName)))
{
/***** Process the class whose name was returned in szClassName *****/
}
aClass = _wpclsEnumClipboardClasses(aFormat, aClass);
}
/* Delete the atom from the system atom table */
WinDeleteAtom(hAtomTable, aFormat);
}
}