如何检查列表中是否已存在某项？

Question

if (this.Handle != hwnd && (Constants.GetWindowLongA(hwnd, Constants.GWL_STYLE) & Constants.TARGETWINDOW) == Constants.TARGETWINDOW)
{
    StringBuilder sb = new StringBuilder(100);
    Constants.GetWindowText(hwnd, sb, sb.Capacity);

    Window t = new Window();
    t.Handle = hwnd;
    t.Title = sb.ToString();
    windows.Add(t);
}

I want to check that if the item variable (t) is already in the List windows don't add it again. Just after the line t.Title = sb.ToString(); to check if it's not exist then add it.

Answer 1

if(!windows.Any(window=>window.Handle == t.Handle)){
    windows.Add(t);
}

Or, better yet, check at the beginning of the method (although I admit I don't know what it's doing.)

if(windows.Any(window=>window.Handle == hwnd)) return;

Answer 2

Did you try the Contains method?

if (!windows.Contains(t)) { windows.Add(t) }

That might work.