如何判断winform窗体有对话框

怎么判断winform窗体有对话框？
如题目～

[解决办法]
获取webbrower内容，判断alert是否存在
[解决办法]
[DllImport("User32.dll", EntryPoint = "FindWindow")]
private static extern IntPtr FindWindow(string lpClassName,string lpWindowName);

IntPtr hWnd = FindWindow(null, "标题");