如何知道鼠标单击child1还是child2，我想实现单击child1弹出一个窗口，如何实现？

LRESULT CALLBACK ProcWinMain(HWND hWnd,UINT Msg,WPARAM wParam,LPARAM lParam)

TV_INSERTSTRUCT tvinsert;
HBITMAP hBitmap;
TV_HITTESTINFO tvhit;

switch (Msg)
{
case WM_CREATE:
    hwndTreeView = CreateWindowEx(NULL, TreeViewClass, NULL, WS_CHILD | WS_VISIBLE | TVS_HASLINES | TVS_HASBUTTONS | TVS_LINESATROOT, 0, 0, 200, 400, hWnd, NULL,
        g_hInstance, NULL);
    hImageList = ImageList_Create(16, 16, ILC_COLOR16, 2, 10);
    hBitmap = LoadBitmap(g_hInstance, MAKEINTRESOURCE(IDB_TREE));
    ImageList_Add(hImageList, hBitmap, NULL);
    DeleteObject(hBitmap);
    SendMessage(hwndTreeView, TVM_SETIMAGELIST, 0, (LPARAM)hImageList);
    tvinsert.hParent = NULL;
    tvinsert.hInsertAfter = TVI_ROOT;
    tvinsert.item.mask = TVIF_TEXT | TCIF_IMAGE | TVIF_SELECTEDIMAGE;
    tvinsert.item.pszText = Parent;
    tvinsert.item.iImage = 0;
    tvinsert.item.iSelectedImage = 1;
    hParent = (HTREEITEM)SendMessage(hwndTreeView, TVM_INSERTITEM, 0, (LPARAM)&tvinsert);
    tvinsert.hParent = hParent;
    tvinsert.hInsertAfter = TVI_LAST;
    tvinsert.item.pszText = Child1;
    SendMessage(hwndTreeView, TVM_INSERTITEM, 0, (LPARAM)&tvinsert);
    tvinsert.item.pszText = Child2;
    SendMessage(hwndTreeView, TVM_INSERTITEM, 0, (LPARAM)&tvinsert);
    break;

case WM_DESTROY:
    PostQuitMessage(0);
    break;
case WM_MOUSEMOVE:
    
    break;
case WM_LBUTTONDOWN:
        
        MessageBox(0, "停止SOCKET", "infor", MB_OK);
        
    break;
case WM_NOTIFY:
{
    
}
break;
default:
    return DefWindowProc(hWnd, Msg, wParam, lParam);
}
return 0;

}
//int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)

WNDCLASSEX wc;
MSG msg;
HWND hWnd;
g_hInstance = hInstance;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = ProcWinMain;
wc.cbClsExtra = NULL;
wc.cbWndExtra = NULL;
wc.hInstance = hInstance;
wc.hbrBackground = (HBRUSH)(COLOR_APPWORKSPACE);
wc.lpszMenuName = NULL;
wc.lpszClassName = ClassName;
wc.hIcon = wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
RegisterClassEx(&wc);

hWnd = CreateWindowEx(WS_EX_CLIENTEDGE, ClassName, AppName, WS_OVERLAPPEDWINDOW,
    CW_USEDEFAULT, CW_USEDEFAULT, 200, 400, NULL, NULL, hInstance, NULL);
ShowWindow(hWnd, SW_SHOWNORMAL);
UpdateWindow(hWnd);

while (GetMessage(&msg, NULL, 0, 0))
{
    TranslateMessage(&msg);
    DispatchMessage(&msg);
}


return msg.wParam;
InitCommonControls();