WPF Application: Assign value in gridviewcell and perform verification

Hi,

Right Now I am working with WPF Application and I spent a lot of time to do some verification, but no success. Help me to do Automation with WPF Application. Our application is not Silverlight it's WPF Application.

Manual testing steps Are:
1) Take value of CurMktVal of one Perticular Fund. 
2) then Enter Value to Proposed alloc Amt ,say $ 50000.
3) Now Value of CurMktVal should be = Value from step 1 + Value From Step 2.
4) Also Want to check for footer Value as well.
5) Compare value of New CurMktVal and New Footer value


Code I tried for step 2 is:

 Telerik.WebAii.Controls.Xaml.Wpf.GridViewCell gCell = ActiveApplication.MainWindow.Find.ByAutomationId<CellElement65Textbox>("CellElement65Textbox");
            gCell.SetFocus();
            gCell.User.Click(MouseClickType.LeftDoubleClick);            
            var PropAlloc = "50000";
            Assert.AreEqual(PropAlloc,gCell.Text);
            gCell.Text = PropAlloc;

Let me know how Should I perform all these Actions. 


Please help me soon, So I can start working on this. I am stuck here.