我创建了TreeView,如下所示:
TreeView=CreateWindowEx(0, WC_TREEVIEW, TEXT("Tree View"), WS_VISIBLE | WS_CHILD, 0, 0, 200, 500, hwnd, (HMENU)ID_TREE_VIEW, GetModuleHandle(NULL), NULL);
现在我添加了一个项目,如本网站所示.
这一切都没关系,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:
如何添加子项(节点)？
如何在每个项目上添加复选框(如何确定是否选中了指定的复选框)？
为了响应OP请求,我添加了一个从父节点中删除复选框的示例.
问题是,当用户选择一个节点并压缩空格键时,仍然会出现CHECKBOX.
这个问题解决了这个问题.
我添加了创建已经检查过的节点的代码.
它是WM_CREATE处理程序中的第二个子节点.
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;
这是解释如何检查项目是否被检查的部分(它现在正确地检查您何时单击复选框以及何时按空格键!):
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消息.
我们使用此消息来填充NMTVKEYDOWN结构,这将为我们提供按下按钮的虚拟键代码以及HWND发送通知的树视图.
现在我们使用TreeView_GetItem()宏来获取当前选择的节点,并且我们检查其状态的方式与我们进行测试时的方式相同.
我唯一的问题是关于此部分的文档TVN_KEYDOWN:
返回值
如果lParam的wVKey成员是字符键代码,则该字符将用作增量搜索的一部分.返回非零以从增量搜索中排除字符,或返回零以在搜索中包含该字符.对于所有其他键,将忽略返回值.
我只是不知道如何处理返回结果,所以我放了0L.
重要说明:如果需要从对话框过程返回值,请使用以下内容:
SetWindowLongPtr( hwnd, DWLP_MSGRESULT, (LONG_PTR)1 );
return TRUE;
请参阅本文档中的返回值备注,而不是使用,因此您可以同时支持和版本. SetWindowLongPtrSetWindowLongx32x64Windows
这就是全部.希望你的问题得到解决.如果您需要进一步的帮助,请发表评论.
我从来没有检查过是否检查了树项目,但我相信这个问题的接受答案是要走的路.
注意:
如果有人可以提供代码片段来展示如何确定treeview节点是否被检查,我将非常感激.