How To Save the Viewing Order of Nodes in a TreeView

MORE INFORMATION

   SET DEFAULT TO SYS(2004)+'SAMPLES\SOLUTION\OLE'
						

   SET DEFAULT TO HOME(2)+'SOLUTION\OLE'

1. Open the BldTree.scx in the Form Designer.
2. Add two new command buttons to the form. (You may have to change the size of the form to do this.)
3. Change the caption of the first new command button to "Add Previous" (without the quotes).
4. Place the following code in the Click event:

         o = THISFORM.oleTree
         IF !ISNULL(o.SelectedItem)
           o.Nodes.Add(o.SelectedItem.Key, 3, THISFORM.NewKey(), "previous",0)
         ENDIF

5. Change the caption of the second new command button to "Save by View Order" (without the quotes).
6. Place the following code in the Click event:

          LOCAL loNodes, lcParent, lcDBFName, lcOldAlias, lcOldSafety, liIndex
          LOCAL liTmp
          #DEFINE WARNING_LOC "Continuing will destroy all data in the " + ;
             "table and create a new table with three fields." + CHR(13) + ;
             "Do you want to continue?"
          #DEFINE WARN_LOC "Warning"
   
          lcOldAlias = ALIAS()
          lcOldSafety = SET("SAFETY")
          lcDBFName = GETFILE("dbf")
   
          IF EMPTY(lcDBFName) && User chose Cancel
            RETURN
          ENDIF
   
          IF FILE(lcDBFName)
            IF THISFORM.OpenDBF(lcDBFName, .T.) AND ;
              THISFORM.VerifyTableStructure() AND ;
              MESSAGEBOX(WARNING_LOC,48+256+4,WARN_LOC) = 6
                   SET SAFETY OFF
                   ZAP
                   SET SAFETY &lcOldSafety
            ELSE
                   RETURN
            ENDIF
          ELSE
            CREATE TABLE (lcDBFName) ;
                (Key c(4), Parent c(4), Text c(60))
          ENDIF
   
          loNodes = THISFORM.oleTree.Nodes
          FOR i = 1 to loNodes.Count
             IF ISNULL(loNodes.Item(i).Parent)
               liIndex = loNodes.Item(i).FirstSibling.Index
               liTmp = liIndex
               EXIT
             ENDIF
          NEXT
   
          lcParent = "0_"  &&Root
          INSERT INTO (lcDBFName) VALUES ;
         (loNodes.Item(liIndex).key, ;
              lcParent, ;
              loNodes.Item(liIndex).Text)
   
          DO WHILE liIndex <> loNodes.Item(liTmp).LastSibling.Index
             INSERT INTO (lcDBFName) VALUES ;
                (loNodes.Item(liIndex).Next.key, ;
                lcParent, ;
                loNodes.Item(liIndex).Next.Text)
                liIndex = loNodes.Item(liIndex).Next.Index
          ENDDO
   
          FOR i = 1 TO loNodes.Count
             IF loNodes.Item(i).Children > 0
                liIndex = loNodes.Item(i).Child.Index
                liTmp = liIndex
                INSERT INTO (lcDBFName) VALUES ;
                   (loNodes.Item(liIndex).key, ;
                   loNodes.Item(liIndex).Parent.Key, ;
                   loNodes.Item(liIndex).Text)
                DO WHILE liIndex <> loNodes.Item(liTmp).LastSibling.Index
                   INSERT INTO (lcDBFName) VALUES ;
                      (loNodes.Item(liIndex).Next.key, ;
                      loNodes.Item(liIndex).Next.Parent.Key, ;
                      loNodes.Item(liIndex).Next.Text)
                      liIndex = loNodes.Item(liIndex).Next.Index
                ENDDO
             ENDIF
          NEXT
   
          USE
   								

7. Save the form as Vfp\Samples\Solution\Ole\Treebld2.scx
8. Run the Form and create a tree by clicking New Root twice. Select the last node in the TreeView control, and then click Add Previous.
9. Click Save DBF to save a table named OldSave.dbf. Then click Save By View Order to save a table named NewSave.dbf.
10. Click Clear, and then click Load DBF to load OldSave.dbf.
11. Repeat step 10 using NewSave.dbf.