按下空格键时,已删除的复选框将再次出现在树视图节点中

时间:2014-03-28 08:53:57

标签: c++ winapi checkbox treeview keyboard-shortcuts

我已使用已接受的解决方案from this question从我的WM_INITDIALOG处理程序中的树视图节点中删除复选框

加载后,具有正确的外观。选择节点并单击复选框所在的位置后,没有任何反应(复选框不会出现),这是正确的行为。

但是,如果我选择节点并按 空格键复选框会自动添加到节点中。

以下是解释问题的WM_INITDIALOG处理程序:

case WM_INITDIALOG:
    {
        // get treeview handle

        HWND TreeView = GetDlgItem( hDlg, IDC_TREE1 );

        /************ enable checkboxes **************/

        DWORD dwStyle = GetWindowLong( TreeView , GWL_STYLE);
        dwStyle |= TVS_CHECKBOXES;
        SetWindowLongPtr( TreeView , GWL_STYLE, dwStyle );

        /************ add items and subitems **********/

        // add root item

        TVINSERTSTRUCT tvis = {0};

        tvis.item.mask = TVIF_TEXT;
        tvis.item.pszText = L"This is root item";
        tvis.hInsertAfter = TVI_LAST;
        tvis.hParent = TVI_ROOT;

        HTREEITEM hRootItem = reinterpret_cast<HTREEITEM>( SendMessage( TreeView ,
            TVM_INSERTITEM, 0, reinterpret_cast<LPARAM>( &tvis ) ) );

        // and here is an example of removing a checkbox 

        TVITEM tvi;
        tvi.hItem = hRootItem ;
        tvi.mask = TVIF_STATE;
        tvi.stateMask = TVIS_STATEIMAGEMASK;
        tvi.state = 0;
        TreeView_SetItem( TreeView, &tvi );

        // add firts subitem for the hTreeItem

        memset( &tvis, 0, sizeof(TVINSERTSTRUCT) );

        tvis.item.mask = TVIF_TEXT;
        tvis.item.pszText = L"This is first subitem";
        tvis.hInsertAfter = TVI_LAST;
        tvis.hParent = hRootItem;

        HTREEITEM hTreeSubItem1 = reinterpret_cast<HTREEITEM>( SendMessage( TreeView ,
            TVM_INSERTITEM, 0, reinterpret_cast<LPARAM>( &tvis ) ) );

        // now we insert second subitem for hRootItem

        memset( &tvis, 0, sizeof(TVINSERTSTRUCT) );

        tvis.item.mask = TVIF_TEXT | TVIF_STATE; // added extra flag
        tvis.item.pszText = L"This is second subitem";
        tvis.hInsertAfter = TVI_LAST;
        tvis.hParent = hRootItem;

        HTREEITEM hTreeSubItem2 = reinterpret_cast<HTREEITEM>( SendMessage( TreeView , 
            TVM_INSERTITEM, 0, reinterpret_cast<LPARAM>( &tvis ) ) );
    }
    return (INT_PTR)TRUE;  

Here引自MSDN:

版本5.80。即使没有图像与项目相关联,也会显示一个复选框

也许这是我问题的原因?

我尝试过处理TVN_KEYDOWN并设置项状态或再次移除复选框,但没有成功。

编辑#2:

我已经将树 Jonathan Potter 建议的方式继承了树,并且它有效:

LRESULT CALLBACK TreeProc( HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam, 
    UINT_PTR uIdSubclass, DWORD_PTR dwRefData )
{
    switch (message)
    {
    case WM_KEYDOWN:
        {
            // reject spacebar if tree node doesn't have checkbox
            if( wParam == VK_SPACE ) 
            {
                HTREEITEM ht = TreeView_GetSelection( hwnd );

                TVITEM tvItem;

                // Prepare to receive the desired information.
                tvItem.mask = TVIF_HANDLE | TVIF_STATE;
                tvItem.hItem = (HTREEITEM)ht;
                tvItem.stateMask = TVIS_STATEIMAGEMASK;

                // Request the information.
                TreeView_GetItem( hwnd, &tvItem );

                // reject if it's not checked, or pass default value otherwise
                switch( tvItem.state >> 12 )
                {
                    case 0:
                        MessageBeep(0);
                        return FALSE;
                        break;
                    case 1:
                    case 2:
                    default:
                        return ::DefSubclassProc( hwnd, message, wParam, lParam );
                        break;
                }               
            }
        }
        break;
    case WM_NCDESTROY:
        ::RemoveWindowSubclass( hwnd, TreeProc, 0 );
        break;
    }
    return ::DefSubclassProc( hwnd, message, wParam, lParam);
}

编辑结束

问题:

如何从树节点 正确删除复选框,以便它再也不会出现

谢谢。

最好的问候。

1 个答案:

答案 0 :(得分:2)

对控件进行子类化,通过WM_KEYDOWN拦截空格键,如果焦点位于您不希望拥有复选框的项目上,则不会传递消息。