UserControl

Add a WPF User Control

namespace WPF 
{ 
   public partial class MyWPF : System.Windows.Controls.UserControl 
   { 
      public MyWPF() 
      { 
         InitializeComponent() 
      } 
   } 
} 

Displays a WPF

System.IntPtr ohandle; 
DataManagerProject.Structure_RECT oRect = new Structure_RECT(); 
System.Windows.Forms.NativeWindow nativeWindow; 
ohandle = Method_HandleGet(Globals.ThisAddIn.Application); 
nativeWindow = new System.Windows.Forms.NativeWindow(); 
nativeWindow.AssignHandle(ohandle); 
Constants.GetWindowRect(ohandle, ref oRect); 

System.Windows.Controls.UserControl myusercontrol; 
myusercontrol = new WPF.MyWPF(); 

System.Windows.Window mywindow = new System.Windows.Window 
{ 
    WindowStyle = System.Windows.WindowStyle.ToolWindow, 
    Title = Constants.MESSAGE_CAPTION + "Title", 
    Content = myusercontrol, 
    ResizeMode = System.Windows.ResizeMode.CanResize, 
}; 

mywindow.Height = 600; 
mywindow.Width = 600; 

int Center_x; 
int Center_y; 
Center_x = oRect.Left + (oRect.Right - oRect.Left) / 2; 
Center_y = oRect.Top + (oRect.Bottom - oRect.Top) / 2; 

int windowCenter_x; 
int windowCenter_y; 
windowCenter_x = Center_x - (int)mywindow.Height / 2; 
windowCenter_y = Center_y - (int)mywindow.Width / 2; 

mywindow.Left = windowCenter_x; // * 72 / 96; 
mywindow.Top = windowCenter_y; // * 72 / 96; 

mywindow.MinHeight = mywindow.Height; 
mywindow.MinWidth = mywindow.Width; 

mywindow.ShowDialog(); 

nativeWindow.ReleaseHandle();