创建带有节点和复选框的 TreeView

2023-12-15

我像这样创建了 TreeView:

TreeView=CreateWindowEx(0, WC_TREEVIEW, TEXT("Tree View"), WS_VISIBLE | WS_CHILD, 0, 0, 200, 500, hwnd, (HMENU)ID_TREE_VIEW, GetModuleHandle(NULL), NULL);

现在我向其中添加了一项,如下所示这个网站.

一切都很好,但经过几个小时的谷歌搜索后,我仍然没有找到这些问题的答案:

  1. 如何添加子项(节点)?

  2. 如何在每个项目上添加复选框(如何确定指定的复选框是否被选中)?


EDIT #4:

为了响应 OP 的请求,我添加了一个从父节点中删除复选框的示例。

问题是当用户选择节点并按空格键时,复选框仍然出现。

这个问题解决了这个问题。

EDIT #3:

我添加了创建已检查节点的代码。

这是第二个子预兆WM_CREATE处理程序。

编辑结束

case WM_CREATE:
    {
        // this is your treeview

        TreeView = CreateWindowEx(0, WC_TREEVIEW, 
            TEXT("Tree View"), WS_VISIBLE | WS_CHILD, 
            0, 0, 200, 500, 
            hwnd, (HMENU)ID_TREE_VIEW, GetModuleHandle(NULL), NULL);

        /************ 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 
        // from a specific item/subitem in case you ever need it

        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;

        // for demonstration purposes let us check this node;
        // to do that add the following code, and add the extra flag for 
        // mask member like above
        tvis.item.stateMask = TVIS_STATEIMAGEMASK;
        tvis.item.state = 2 << 12;

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

        // let us expand the root node so we can see if checked state is really set
        TreeView_Expand( TreeView, hRootItem, TVE_EXPAND );
    }
    return 0L;

EDIT #2:

这是解释如何检查项目是否已选中的部分(现在,当您单击复选框和按空格键时,它会正确检查! ) :

case WM_NOTIFY:
    {
        LPNMHDR lpnmh = (LPNMHDR) lParam;

        if( lpnmh->idFrom == ID_TREE_VIEW  )  // if this is our treeview control
        {
            switch( lpnmh->code )  // let us filter notifications
            {
            case TVN_KEYDOWN:  // tree has keyboard focus and user pressed a key
                {

                    LPNMTVKEYDOWN ptvkd = (LPNMTVKEYDOWN)lParam; 

                    if( ptvkd->wVKey == VK_SPACE )  // if user pressed spacebar
                    {

                        // get the currently selected item
                        HTREEITEM ht = TreeView_GetSelection( ptvkd->hdr.hwndFrom );

                        // Prepare to test items state

                        TVITEM tvItem;

                        tvItem.mask = TVIF_HANDLE | TVIF_STATE;
                        tvItem.hItem = (HTREEITEM)ht;
                        tvItem.stateMask = TVIS_STATEIMAGEMASK;

                        // Request the information.
                        TreeView_GetItem( ptvkd->hdr.hwndFrom, &tvItem );

                        // Return zero if it's not checked, or nonzero otherwise.
                        if( (BOOL)(tvItem.state >> 12) - 1 )
                            MessageBox( hwnd, L"Not checked!", L"", MB_OK );
                        else
                            MessageBox( hwnd, L"Checked!", L"", MB_OK );

                    }
                }
                return 0L;  // see the documentation for TVN_KEYDOWN

            case NM_CLICK:  // user clicked on a tree
                {
                    TVHITTESTINFO ht = {0};

                    DWORD dwpos = GetMessagePos();

                    // include <windowsx.h> and <windows.h> header files
                    ht.pt.x = GET_X_LPARAM(dwpos);
                    ht.pt.y = GET_Y_LPARAM(dwpos);
                    MapWindowPoints( HWND_DESKTOP, lpnmh->hwndFrom, &ht.pt, 1 );

                    TreeView_HitTest(lpnmh->hwndFrom, &ht);

                    if(TVHT_ONITEMSTATEICON & ht.flags)
                    {
                        // Prepare to receive the desired information.

                        TVITEM tvItem;

                        tvItem.mask = TVIF_HANDLE | TVIF_STATE;
                        tvItem.hItem = (HTREEITEM)ht.hItem;
                        tvItem.stateMask = TVIS_STATEIMAGEMASK;

                        // Request the information.
                        TreeView_GetItem( lpnmh->hwndFrom, &tvItem );

                        // Return zero if it's not checked, or nonzero otherwise.
                        if( (BOOL)(tvItem.state >> 12) - 1 )
                            MessageBox( hwnd, L"Not checked!", L"", MB_OK );
                        else
                            MessageBox( hwnd, L"Checked!", L"", MB_OK );

                    }
                }
            default:
                break;
        }
    }
}
break;

按下空格键时正确测试的相关想法是处理TVN_KEYDOWN信息。

我们使用这个消息来获取NMTVKEYDOWN结构填充,这将为我们提供按下按钮和HWND发送通知的树视图。

现在我们使用TreeView_GetItem()宏来获取当前选定的节点,我们检查其状态的方式与进行命中测试时的方式相同。

我唯一的问题是关于文档中的这一部分TVN_KEYDOWN:

返回值

如果lParam的wVKey成员是字符键码,则字符 将用作增量搜索的一部分。返回非零到 从增量搜索中排除该字符,或包含零 搜索中的字符。对于所有其他键,返回值为 被忽略。

我只是不知道如何处理返回结果,所以我把0L.

重要的提示:如果您需要从对话框过程返回值,请使用如下所示:

SetWindowLongPtr( hwnd, DWLP_MSGRESULT, (LONG_PTR)1 );
return TRUE;

请参阅备注 返回值在本文档中并使用SetWindowLongPtr代替SetWindowLong所以你可以同时支持x32 and x64的版本Windows.

仅此而已。希望您的问题得到解决。如果您需要进一步的帮助,请发表评论。

编辑结束

我从未检查过树项目是否已检查,但我相信接受这个问题的答案是要走的路。

NOTE:

如果有人可以提供代码片段来展示如何确定是否treeview节点是否被检查。

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