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Expanding a branch

Posted by Zafir Anjum on August 6th, 1998

The treeview has built in support for expanding expanding the outline one level at a time. If you want to completely expand a branch, the code below will help. It uses recursion to expand all items. The last line, that is, the call to EnsureVisible() is useful when this code is hooked up to a user interface. After expanding the outline branch, the previously selected item may have scrolled off and calling EnsureVisible() brings it back.
  
// ExpandBranch - Expands a branch completely
// hti          - Handle of the tree item to expand
void CTreeCtrlX::ExpandBranch( HTREEITEM hti )
{
        if( ItemHasChildren( hti ) ){
                Expand( hti, TVE_EXPAND );
                hti = GetChildItem( hti );
                do{
                        ExpandBranch( hti );
                }while( (hti = GetNextSiblingItem( hti )) != NULL );
        }
        EnsureVisible( GetSelectedItem() );
}

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Comments

  • How do I check if the branch is expanded?

    Posted by Legacy on 06/19/2002 12:00am

    Originally posted by: Todd

    When I do drag and drop I want to redraw the items in another branch, the problem is that when I redraw the other branches they collapse. Is there a way to check if an item is expanded so I can expand the branches that the user had selected before the redraw?

    Reply

  • For the people who like recursion

    Posted by Legacy on 02/25/2002 12:00am

    Originally posted by: Amir Geva 

    Here is a simple recursive no loop implementation:


    void MyTreeCtrl::ExpandAll(HTREEITEM item, UINT nCode=TVE_EXPAND, bool siblings=false) 

    {

      if (item!=NULL) 

      {

        Expand(item,nCode);

        ExpandAll(GetChildItem(item),nCode,true);

        if (siblings) ExpandAll(GetNextSiblingItem(item),nCode,true);

      }

    }

    Reply

  • Expanding/Collapsing with numeric pad

    Posted by Legacy on 01/28/2000 12:00am

    Originally posted by: Jean Claude DAUPHIN

    It seems to be a Tree Ctrl UI standard feature:

    Keyboard "*","+" on numeric pad allow to expand the branch
    under the selected item.
    Keyboard "-" on numeric pad allow to collapse the branch under the selected item.

    Reply

  • Another way

    Posted by Legacy on 07/24/1999 12:00am

    Originally posted by: Ant Htoo Naing 

    U can use this method if you don't use VK_MULTIPLY( "*" key from Numeric Key Pad) for another purpose.


    void CTreeCtrlEx::ExpandBranch(HTREEITEM hItem)

    {

            HTREEITEM hSelectItem=GetSelectedItem();


    	SelectItem(hItem);

            SendMessage(WM_KEYDOWN,VK_MULTIPLY);


            if (hSelectItem==NULL)

    		hSelectItem=GetRootItem();

            EnsureVisible(hSelectItem);

            SelectItem(hSelectItem);

    }

    Reply

  • How about change like this?

    Posted by Legacy on 07/10/1999 12:00am

    Originally posted by: Eung-Yeon, Kim 

    I think the bellow code occurs some problem when hti is NULL


       =>        if( ItemHasChildren( hti ) ){


    Because hti may be NULL if The tree has not Child Item


       =>        hti = GetChildItem(hti);


    

    So, How about rewrite the code like bellow 


    // ExpandBranch - Expands a branch completely

    // hti          - Handle of the tree item to expand

    void CTreeCtrlX::ExpandBranch( HTREEITEM hti )

    {

         => if( ItemHasChildren( hti ) && hti != NULL){

                    Expand( hti, TVE_EXPAND );

                    hti = GetChildItem( hti );

                    do{

                            ExpandBranch( hti );

                    }while( (hti = GetNextSiblingItem( hti )) ! 

                                                       = NULL );

            }

            EnsureVisible( GetSelectedItem() );

    }

    Reply

  • Memory fault!!

    Posted by Legacy on 06/08/1999 12:00am

    Originally posted by: Seo-Wooseok 

    When I used this way, Windows98 send 'memory fault' message.


    Because my TreeCtrl has so many tree item. So, Windows98's memory overflowed. I think so.


    Then, how can I solve this problem?


    Thank you for reading..

    Reply
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