WPF

void REQNode_MouseMove(object sender, MouseEventArgs e)
     {
         if (e.LeftButton == MouseButtonState.Pressed)
         {
             TreeViewItem tvi = sender as TreeViewItem;
             dragContext = tvi.Tag as REQRequirement;
             DragDrop.DoDragDrop(tvi,dragContext, DragDropEffects.Copy);
         }
     }
     private void txtPostCond_DragOver(object sender, DragEventArgs e)
     {
         if (e.Data.GetDataPresent(typeof(REQRequirement)))
         {
             e.Effects = DragDropEffects.Copy;
         }
         else
         {
             e.Effects = DragDropEffects.None;
         }
     }

     public void txtPostCond_Drop(object sender, DragEventArgs e)
     {
         if (e.Data.GetDataPresent(typeof(REQRequirement)))
         {
             REQRequirement req = (REQRequirement)e.Data.GetData(typeof(REQRequirement));
             txtPostCond.Text = req.Description;
         }
     }

for (int i = 0; i < 65; i++)
           {
               TextBlock b1 = new TextBlock() { Text = i.ToString(), ToolTip = GetInformationFromXML(i, 0) };
               Grid.SetColumn(b1, 0);
               Grid.SetRow(b1, i);
               g.Children.Add(b1);

               if (i != 0)
               {
                   TextBlock b2 = new TextBlock() { Text = i.ToString(), ToolTip = GetInformationFromXML(i, 0) };
                   Grid.SetColumn(b2, i);
                   Grid.SetRow(b2, 0);
                   g.Children.Add(b2);
               }
           }

MyObject o = (MyObject)e.OriginalSource;
int X = o.GridPositionX;
int Y = o.GridPositionY;

TextBlock tb1 = (TextBlock)grid.GetItem(X,0);
TextBlock tb2 = (TextBlock)grid.GetItem(0,Y);