Dynamically Adding Columns to a Databound XamDataGrid

Hello All,

One approach I've tried to solve my problem of needing to be able to dynamically add columns to a databound xamDataGrid is to bind to a .NET DataTable. At startup, I hard-code some data into the DataTable. Then I provide a button which, when clicked, is supposed to add a new column and put random numbers in the new column. I then unbind and rebind the xamDataGrid. Oddly, I see only the original columns. My newly-added column does not show up. Here's the code:

Window1.xaml.cs:

using System;
using System.Windows;

namespace XamDataGridBoundToDataTable
{
   /// <summary>
   /// Interaction logic for Window1.xaml
   /// </summary>
   public partial class Window1 : Window
   {
      public Window1()
      {
         InitializeComponent();
      }

      private void Window_Loaded(object sender, RoutedEventArgs e)
      {
         m_myDataGrid.DataSource = MyDataTable.Instance.Rows;
      }

      private void m_addColumnButton_Click(object sender, RoutedEventArgs e)
      {
         int ColNum = MyDataTable.Instance.Columns.Count + 1;
         string columnName = string.Format("Column {0}", ColNum);

         MyDataTable.Instance.Columns.Add(columnName, typeof(int));
         MyDataTable.Instance.Rows[0][columnName] = m_rand.Next(100);
         MyDataTable.Instance.Rows[1][columnName] = m_rand.Next(100);

         m_myDataGrid.DataSource = null;
         m_myDataGrid.FieldLayouts.Clear();
         m_myDataGrid.DataSource = MyDataTable.Instance.Rows;
      }

      private readonly Random m_rand = new Random();
   }
}

App.xaml.cs:

using System.Windows;

namespace XamDataGridBoundToDataTable
{
   /// <summary>
   /// Interaction logic for App.xaml
   /// </summary>
   public partial class App : Application
   {
      private void HandleStartup(object sender, StartupEventArgs e)
      {
         MyDataTable.Instance.Columns.Add("Column 1", typeof(int));
         MyDataTable.Instance.Columns.Add("Column 2", typeof(int));
         MyDataTable.Instance.Columns.Add("Column 3", typeof(int));

         MyDataTable.Instance.Rows.Add(new object [] {243, null, 158});
         MyDataTable.Instance.Rows.Add(new object[] {17, 42, 144});
      }
   }
}

MyDataTable.cs:

using System.Data;

namespace XamDataGridBoundToDataTable
{
   class MyDataTable : DataTable
   {
      static MyDataTable()
      {
         Instance = new MyDataTable();
      }

      public static MyDataTable Instance { get; private set; }
   }
}

Can anybody fathom a reason why I'm still seeing only the original columns even after unbinding and rebinding?

Thanks, Dave

ansaurus

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Dynamically Adding Columns to a Databound XamDataGrid

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