MVP Pattern

<UserControl x:Class="Namespace.Forms.MyForm_View" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation 
   MinHeight= 
   MinWidth= 
   Height= 
   Width= 
> 

Add a "User Control (WPF)"
Add a reference System.Xaml
Remove the ".Forms" entry in the namepsace

copy the height and width from the usercontrol

Forms.FormatTable_Model oModel = new Forms.FormatTable_Model(); 

General.g_oThread = new System.Threading.Thread(delegate () 
{ 
    System.Windows.Controls.UserControl myusercontrol; 
    myusercontrol = new Forms.FormatTable_View(); 

    Forms.FormatTable_View oView2 = (Forms.FormatTable_View)myusercontrol; 
    Forms.FormatTable_Presenter oPresenter = new Forms.FormatTable_Presenter(oModel, oView2); 

    General.g_oMyWindow = new System.Windows.Window() 
    { 
        Title = Constants.MESSAGE_CAPTION + "Format Table", 
        Content = myusercontrol, 
        ShowInTaskbar = false, 
        ResizeMode = System.Windows.ResizeMode.NoResize, 
        Height = myusercontrol.Height + 30, 
        Width = myusercontrol.Width + 6 
    }; 

    //positioning in the center 
    General.g_oInteropHelper = new System.Windows.Interop.WindowInteropHelper(General.g_oMyWindow); 
    General.g_oInteropHelper.Owner = (System.IntPtr)General.g_oExcel.Application.Hwnd; 

    Constants.Structure_RECT oRect; 
    General.GetWindowRect((System.IntPtr)General.g_oExcel.Application.Hwnd, out oRect); 
    int nonWPFOwnerLeft = oRect.Left; 
    int nonWPFOwnerWidth = oRect.Right - oRect.Left; 
    int nonWPFOwnerTop = oRect.Top; 
    int nonWPFOwnerHeight = oRect.Bottom - oRect.Top; 

    General.g_oMyWindow.WindowStartupLocation = System.Windows.WindowStartupLocation.Manual; 
    General.g_oMyWindow.Left = nonWPFOwnerLeft + (nonWPFOwnerWidth - General.g_oMyWindow.Width) / 2; 
    General.g_oMyWindow.Top = nonWPFOwnerTop + (nonWPFOwnerHeight - General.g_oMyWindow.Height) / 2; 

    General.g_oMyWindow.ShowDialog(); 

    System.Windows.Threading.Dispatcher.Run(); 
}); 

General.g_oThread.SetApartmentState(System.Threading.ApartmentState.STA); 
General.g_oThread.Start();