I implemented a variable number of columns by doing:

 

The datagrid .DataSource is set to a List<RowData>

 

public class RowData

{

/// <summary>

/// Array of CellData, makes up everything shown in a row on the grid

/// </summary>

private CellData[] _rowData;

public CellData[] Cells

{

get { return _rowData; }

set { _rowData = value; }

}

}

 

Then the field layout is generated from fields setup like:

UnboundField field = new UnboundField();

field.DataType = typeof(object);

field.BindingPath = new PropertyPath("Cells[" + index + "].Value");

 

CellData.Value returns an object, based on what is going to be shown in the column it sets up EditorType and EditAsType according to what is actually inside the object

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 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: MyDataTable.cs -------------- using System.Data; namespace XamDataGridBoundToDataTable { class MyDataTable : DataTable { static MyDataTable() { Instance = new MyDataTable(); } public static MyDataTable Instance { get; private set; } } } Window1.xaml.cs --------------- using System; using System.Windows; namespace XamDataGridBoundToDataTable { /// /// Interaction logic for Window1.xaml /// 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 { /// /// Interaction logic for App.xaml /// 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}); } } } Can anybody fathom a reason why I'm still seeing only the original columns even after unbinding and rebinding? Thanks, Dave