WPF Forms : How to bulild Multiple Combo boxes dynamically

Question

I have used the below code to achieve the requirement. But Only last comb box is displaying on the screen.

 

suppose i am trying to display 10 comboxes to display on the screen. But only 10th one is displaying on the screen

 

I am trying to add the combo boxes to canvas (ReportDropDown is my canvas name )

for(int j =0; j < itemsCount; j++)
{
   ComboBox Itembox = new ComboBox();
   Itembox.Margin = new Thickness(10,10,0,13);
   Itembox.HorizontalAlignment = HorizontalAlignment.Left;
   Itembox.VerticalAlignment = VerticalAlignment.Top;
   Itembox.Width = 194;
   Itembox.Height = 30;
   Itembox.IsEditable = false;
   Itembox.Name = "ReportData" + j.ToString() ;
   ComboBoxItem cboxItem = new ComboBoxItem();
   cboxItem.Content = ActualColumnsList[j];
   Itembox.Items.Add(cboxItem);
   ReportDropDown.Children.Add(Itembox);
}