I am creating a grid with 3 columns:

      model = new GridModel();

      model.DataSource = _db.getColumnSelectGridItems();

      model.Columns.Add(new GridColumn("Column Name", "ColumnName", "string", "150"));
      model.Columns.Add(new GridColumn("Selected", "Selected", "bool", "100"));
      model.Columns.Add(new GridColumn("Filter", "Filter", "string", "150"));

I want to be able to edit both the 'Filter' and 'Selected' columns but not the 'Column Name' column.  Here's what I'm trying:

      var updating = new GridUpdating();
      updating.EnableAddRow = false;
      updating.EnableDeleteRow = false;
      updating.ColumnSettings.Add(new ColumnUpdatingSetting() { ColumnKey= "ColumnName", ReadOnly = true });

      model.Features.Add(updating);

Obviously its not working.  What am I missing?