When the user drops the objects, a DM_DROP message is sent to the target, providing it with the information necessary to process the objects that were dropped. The target application uses the information provided to exchange data with the source. The target is responsible for establishing the appropriate conversations, and the source must cooperate in establishing the necessary conversations to achieve the actual data exchange. After completing the direct manipulation operation, including the post-drop conversation with the source, the target uses DrgDeleteStrHandle or DrgDeleteDraginfoStrHandles to delete the string handles in the DRAGINFO data structure, and DrgFreeDraginfo to release the storage. The target should immediately remove any target emphasis. The data transfers must not be done before responding to the DM_DROP message.

The following sample code shows how a target processes an object that has been dropped on it. This code fragment is part of a complete program which is illustrated in "Sample Code for Direct Manipulation".

        /* Drop the object on us (receive the object) */
        case DM_DROP:

         /* Get access to the DRAGINFO data structure */
         DrgAccessDraginfo(dragInfo);

         /* Can we accept this drop? */
         switch (dragInfo->usOperation)
         {

           /* Return DOR_NODROPOP if current */
           /* operation is link or unknown.  */
           case DO_UNKNOWN:
              DrgFreeDraginfo(dragInfo);
              return (MRFROM2SHORT (DOR_NODROPOP, 0));
              break;

           /* Our default operation is Move */
           case DO_DEFAULT:
              dragItem = DrgQueryDragitemPtr(dragInfo, 0);
              ulBytes = DrgQueryStrName(dragItem->hstrContainerName,
                                                  sizeof(szDir),
                                                  szDir);
              if(!ulBytes)
                return (MRFROM2SHORT (DOR_NODROPOP, 0));
              usOp = (USHORT)DO_MOVE;
              break;

           /* Do the requested specific operation */
           case DO_MOVE:
           case DO_COPY:
              usOp = dragInfo->usOperation;
              break;
          }

          usIndicator = DOR_DROP;
          cItems = DrgQueryDragitemCount(dragInfo);

          /* Now, we need to look at each item in turn */
          for (i = 0; i < cItems; i++)
          {
            dragItem = DrgQueryDragitemPtr(dragInfo, i);

            /* Make sure we can move for a Move request */
            /* or copy for a Copy                       */
            if (((dragItem->fsSupportedOps & DO_COPYABLE)   &&
                 (usOp == (USHORT)DO_COPY))                 ||
                ((dragItem->fsSupportedOps & DO_MOVEABLE)   &&
                 (usOp == (USHORT)DO_MOVE)))

            {
               /* Check the rendering format */
               if (DrgVerifyRMF(dragItem, "DRM_OS2FILE", "DRF_UNKNOWN"))
                  usIndicator = DOR_DROP;
               else
                  usIndicator = DOR_NEVERDROP;
            }
            else
               usIndicator = DOR_NODROPOP;

/***********************************************************************/
/*  This is where we would actually move or copy the file,             */
/*  but we just display the name instead.                              */
/***********************************************************************/
            DrgQueryStrName(dragItem->hstrSourceName, 255, szBuffer);
            WinMessageBox(HWND_DESKTOP,
                          HWND_DESKTOP,
                          szBuffer,
                          "Dropped",
                          0,
                          MB_OK);
          }
          /* Release the draginfo data structure */
          DrgFreeDraginfo(dragInfo);

          return (MRFROM2SHORT(usIndicator, usOp));
          break;