问如何将焦点赋予已创建的窗口，而不是创建新实例？

EN

private YourWindow wnd = null;

void OnButton_Click()
{
    if (wnd == null) wnd = new YourWindow();
    wnd.Show();
}

 Public Class FormsCollection
        Public Shared Forms As ArrayList = New ArrayList
    End Class

    Public Function Find_form(strForm_name As String)
        For Each F In FormsCollection.Forms
            If F.ToString = strForm_name Then
                Find_form = F
                Exit Function
            End If
        Next
        Find_form = Nothing
    End Function

Dim FormToOpen As FormToOpen
            If IsNothing(Find_form("FormToOpen")) Then
                FormToOpen = New FormToOpen
            Else
                FormToOpen = Find_form("FormToOpen ")
            End If
            With FormToOpen
                .Owner = Me
                .ShowDialog()
            .Activate
                        End with

List<Window> allWindows = new List<Window>();

// ... elsewhere I want to create a ShinyWindow
void ActivateShinyWindow()
{
    var shiny = allWindows.OfType<ShinyWindow>().FirstOrDefault();
    if (shiny == null)
    {
        shiny = new ShinyWindow();
        allWindows.Add(shiny);
    }
    ActivateWindow(shiny);
}