Using Convert Callbacks

The convert callback provides data to the drop zone when a drop occurs. The first action in the convert callback is a verification of the reason field in the callData. If the reason is not DtCR_CONVERT_DATA or DtCR_CONVERT_DELETE, you should return immediately; otherwise, proceed to convert the data. For example, if you are handling the conversion of a file name, retrieve the appropriate file name from your internal data structures and copy it into the file data object. If your drag source supports the move operation, you need to support conversion of the DELETE target. That is, when convertCallback is called with a reason of DtCR_CONVERT_DELETE, perform the appropriate deletion action for the data that was moved. In the case of the file transfer, delete the file. Here is a simple convertCallback that handles the conversion and deletion of file names.

void
convertFileCallback(
 	Widget dragContext,
 	XtPointer clientData,
 	XtPointer callData) 
{
 	DtDndConvertCallbackStruct *convertInfo =	(DtDndConvertCallbackStruct*)
  allData;
 	char	 *fileName = (char *) clientData;
  	if (convertInfo->reason == DtCR_DND_CONVERT_DATA) 
   {
		convertInfo->dragData->data.files[0]=
 				XtNewString(fileName); 	
   }

else if (convertInfo->reason == DtCR_DND_CONVERT_DELETE)
   {
		deleteFile(fileName);
 	} else {
 	convertInfo->status = DtDND_FAILURE;
 	}

}