Brief Description of Issue:

dnnGrid works fine with automatically generated columns. But when I tried to add columns to dnnGrid programmatically (from DataTable) - Grid is created, but Column Headers are missing

Clear Steps to Reproduce:
1. Create ASCX page with the following controls (placeholders):

<%@ Control language="C#" Inherits="Fobos.Modules.TestPage" CodeFile="TestPage.ascx.cs" AutoEventWireup="true"%>
<h2>Example 1. dnnGrid - Auto Generated Columns</h2>
<asplaceHolder ID="phlAutoGrid" runat="server"></asplaceHolder>
<br />
<h2>Example 2. dnnGrid - Programmatically created Columns</h2>
<asplaceHolder ID="phlProGrid" runat="server"></asplaceHolder>

2. Create CS page with Code (any data source could be used):

using System;
using System.Data;
using System.Collections;
using System.Collections.Generic;
using System.Reflection;
using System.Web.UI;
using System.Web.UI.WebControls;

using DotNetNuke;
using DotNetNuke.Common.Utilities;
using DotNetNuke.Entities.Modules;
using DotNetNuke.Entities.Modules.Actions;
using DotNetNuke.Security;
using DotNetNuke.Services.Exceptions;
using DotNetNuke.Services.Localization;

using System.Configuration;
using Microsoft.ApplicationBlocks.Data;
using DotNetNuke.Web.UI.WebControls;

namespace Fobos.Modules
{
/// ----------------------------------------------------------------------------- /// <summary>
/// The ViewFobos class displays the content
/// </summary>
/// <remarks>
/// </remarks>
/// <history>
/// </history>
/// ----------------------------------------------------------------------------- partial class TestPage : PortalModuleBase
{
protected void Page_Load(System.Object sender, System.EventArgs e)
{
try
{
if (!Page.IsPostBack)
{
// populate Grid with Automatically generated columns
MakeAutoGeneratedGrid();
// populate Grid with Programmatically created Columns
MakeGridByProgram();
}
else
{

}

}
catch (Exception exc) //Module failed to load
{
//Exceptions.ProcessModuleLoadException(this, exc);
}

}

protected void MakeAutoGeneratedGrid()
{
// define new Grid & add to page placeholder
DnnGrid grdTest = new DnnGrid();
phlAutoGrid.Controls.Add(grdTest);
// Set Grid Properties
grdTest.AllowPaging = true;
grdTest.AllowSorting = true;
grdTest.AutoGenerateColumns = true;
grdTest.ShowHeader = true;
// Data Binding
grdTest.DataSource = GetDataTable();
grdTest.DataBind();

}

protected void MakeGridByProgram()
{
// define new Grid & add to page placeholder
DnnGrid grdProTest = new DnnGrid();
phlProGrid.Controls.Add(grdProTest);
// Set Grid Properties
grdProTest.AllowPaging = true;
grdProTest.AllowSorting = true;
grdProTest.AutoGenerateColumns = false;
grdProTest.ShowHeader = true;
// Data Source
DataTable MyDataTable=GetDataTable();
grdProTest.DataSource = MyDataTable;
// Add Bound Columns to Grid
DnnGridBoundColumn MyGridColumn;
// Loop in DataSource Columns
foreach (DataColumn MySourceColumn in MyDataTable.Columns)
{
MyGridColumn = new DnnGridBoundColumn();
grdProTest.MasterTableView.Columns.Add(MyGridColumn);
MyGridColumn.DataField = MySourceColumn.ColumnName;
MyGridColumn.DataType = MySourceColumn.DataType;
MyGridColumn.HeaderText = MySourceColumn.ColumnName;
}

// Data Binding
grdProTest.Rebind(); // grdProTest.DataBind() - could be used too, no changes in result

}//MakeGridByProgram

public DataTable GetDataTable()
{
// Get Connection String to test Database ("VendorDB")
String strConnectionString = ConfigurationManager.ConnectionStrings["VendorDB"].ToString();
String strSQL = "Select * FROM dbo.US_ZIP";
// Get Data Table
DataTable dtZip = SqlHelper.ExecuteDataset(strConnectionString, CommandType.Text, strSQL).Tables[0];
return(dtZip);
}

}
}

Actual Result:
1. Two grid created, but second one (with programmatically created columns) does not have Column Headers.

Expected Result:
Grids must be identical