HOWTO: Use OLE Drag and Drop to Exchange Data Between Apps (186583)


The information in this article applies to:

  • Microsoft Visual FoxPro for Windows 6.0
This article was previously published under Q186583

SUMMARY

Visual FoxPro now supports OLE Drag and Drop, a powerful and useful tool that allows creation of tools and applications that are more readily and seamlessly integrated with other applications. Using OLE drag and drop functionality, you can move data between applications that support the OLE drag and drop interface (such as Visual FoxPro, Visual Basic, Windows Explorer, Microsoft Word, Microsoft Excel, and so forth). This article illustrates one approach to exchanging data between applications.

MORE INFORMATION

The OLE Drag and Drop features in Visual FoxPro 6.0 are designed to allow creation of tools and applications that are readily integrated with other Windows applications, Visual Studio components and the Windows desktop.

The sample code in this article illustrates the process of exchanging data involving graphic data files between a Visual FoxPro application and other Windows applications.

  1. Create a program file named Oledemo.prg, using the following code: 

          PUBLIC ox
      ox=CREATEOBJECT("frmlist")
      ox.SHOW

      DEFINE CLASS frmlist AS FORM
         AUTOCENTER=.T.
         TOP = 0
         LEFT = 0
         HEIGHT = 200
         WIDTH = 400
         DOCREATE = .T.
         OLEDRAGMODE = 1
         OLEDROPMODE = 1
         CAPTION = "OLE Drag And Drop Form"
         NAME = "Form1"

      ADD OBJECT list1 AS LISTBOX WITH ;
         OLEDRAGMODE = 0, ;
         OLEDROPMODE = 0, ;
         HEIGHT = 156, ;
         LEFT = 24, ;
         MULTISELECT = .T., ;
         TOP = 12, ;
         WIDTH = 121, ;
         NAME = "List1"

      ADD OBJECT image1 AS IMAGE WITH ;
         OLEDRAGMODE = 1, ;
         OLEDROPMODE = 1, ;
         HEIGHT = 180, ;
         LEFT = 210, ;
         TOP = 10, ;
         WIDTH = 180, ;
         NAME = "IMAGE1", ;
         STRETCH=2

      PROCEDURE INIT
         THIS.getpicfiles()
      ENDPROC

      PROCEDURE LOAD
         PUBLIC labmpfiles
         DECLARE labmpfiles[1]
      ENDPROC

      PROCEDURE getpicfiles
         =ADIR(labmpfiles,HOME(4)+'\BITMAPS\ASSORTED\*.BMP')
         FOR i=1 TO ALEN(labmpfiles,1)
            if UPPER(RIGHT(labmpfiles[i,1],3))="BMP"
               THISFORM.list1.ADDITEM(labmpfiles[i,1])
            ENDIF
         NEXT
      ENDPROC

      PROCEDURE list1.MOUSEDOWN
         LPARAMETERS nbutton, nshift, nxcoord, nycoord
         THIS.OLEDRAG(.t.)
      ENDPROC

      PROCEDURE list1.OLESTARTDRAG
         LPARAMETERS odataobject, neffect
         odataobject.CLEARDATA
         odataobject.SETFORMAT( 15 )
      ENDPROC

      PROCEDURE list1.OLESETDATA
         LPARAMETERS odataobject, eformat
         LOCAL afiles[ 1 ], nlen, ctext
         nlen = 0
         IF eformat == 15 && Files
            FOR i = 1 TO THIS.LISTCOUNT
               IF THIS.SELECTED(i)
                  nlen = nlen + 1
                  DIMENSION afiles[nLen]
                 afiles[nLen] = HOME(4)+'BITMAPS\ASSORTED\'+THIS.LIST(i)
               ENDIF
            NEXT
            odataobject.SETDATA( @afiles, 15 )
         ENDIF
      ENDPROC

      PROCEDURE image1.OLEDRAGDROP
         LPARAMETERS odataobject, neffect, nbutton, nshift, nxcoord, ;
            nycoord
         LOCAL cfilename, afiles[ 1 ]
         IF odataobject.GETFORMAT( 15 )
            odataobject.GETDATA( 15, @afiles )
            FOR EACH cfilename IN afiles
               THIS.PICTURE = cfilename
               INKEY( .5 )
            NEXT
         ENDIF
      ENDPROC

      PROCEDURE image1.OLEDRAGOVER
         LPARAMETERS odataobject, neffect, nbutton, nshift, nxcoord, ;
            nycoord, nstate
         DO CASE
            CASE nstate = 0 && Drag Enter
               IF odataobject.GETFORMAT(15)
                     THIS.OLEDROPHASDATA = 1
                     THIS.OLEDROPEFFECTS = 4
                     neffect = 4
                  ENDIF
               CASE nstate = 1 && DRAG_LEAVE
               CASE nstate = 2 && DRAG_OVER
            ENDCASE
            THISFORM.REFRESH
         ENDPROC

      ENDDEFINE

  2. In Command window, type the following: 

          DO OLEDEMO

  3. Select any item in the list box appearing on the form. Holding the left mouse button down, drag the selected item to the image control. The selected graphic image appears in the image control.
  4. Select any item in the list box appearing on the form. Holding the left mouse button down, drag the selected item to the Command window. The default Bitmap Editor opens with the selected graphic image.
  5. Start Windows Explorer. Select any graphics file (ani, .bmp, .cur, .gif, .ico, or .jpg). Holding the left mouse button down, drag the selected item from Windows Explorer to the image control. The selected graphic image appears in the image control.
  6. Start Microsoft Word. Select any item in the list box appearing on the form. Holding the left mouse button down, drag the selected item to an open Microsoft Word document. The selected graphic image appears in the open Word document.

REFERENCES

Visual FoxPro Books Online: Programmer's Guide; Chapter 31 - Interoperability and the Internet; OLE Drag and Drop topic.

(c) Microsoft Corporation 1998, All Rights Reserved. Contributions by John Desch, Microsoft Corporation
Modification Type:MinorLast Reviewed:7/13/2004
Keywords:kbhowto KB186583 kbAudDeveloper
©2004 Microsoft Corporation. All rights reserved.