Grid View for ASP.NET Web Forms - How to dynamically switch the Grid's data source and recreate columns at runtime

C#
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using DevExpress.Web;

public partial class _Default : System.Web.UI.Page {
    protected void ASPxGridView1_Load(object sender, EventArgs e) {
        // set DataSource
        ASPxGridView1.DataSource = GetCurrentTable();
        // create columns, if necessary
        EnsureColumns();
        // call DataBind()
        ASPxGridView1.DataBind();
    }

    private DataTable GetCurrentTable() {
        if(ASPxRadioButton1.Checked)
            return GetTable1();
        else
            return GetTable2();
    }

    private DataTable GetTable1() {
        DataTable dt = (DataTable)Session["Table1"];
        if(dt == null) {
            dt = new DataTable();
            dt.Columns.Add("ID1");
            dt.Columns.Add("Data1");
            for(int i = 0; i < 5; i++)
                dt.Rows.Add(i, "row 1 " + i.ToString());
            Session.Add("Table1", dt);
        }
        return dt;
    }
    private DataTable GetTable2() {
        DataTable dt = (DataTable)Session["Table2"];
        if(dt == null) {
            dt = new DataTable();
            dt.Columns.Add("ID2");
            dt.Columns.Add("Data2");
            for(int i = 0; i < 10; i++)
                dt.Rows.Add(i, "row 2 " + i.ToString());
            Session.Add("Table2", dt);
        }
        return dt;
    }

    private void EnsureColumns() {
        if(ASPxGridView1.Columns.Count == 0)
            ReCreateColumns();
        else {
            DataTable table = GetCurrentTable();
            // if the grid has other columns than the assigned data source, 
            // recreate columns
            if(ASPxGridView1.Columns[table.Columns[0].ColumnName] == null)
                ReCreateColumns(); 
        }
    }

    private void ReCreateColumns() {
        ASPxGridView1.Columns.Clear();

        DataTable table = GetCurrentTable();
        foreach(DataColumn dataColumn in table.Columns) {
            GridViewDataTextColumn column = new GridViewDataTextColumn();
            column.FieldName = dataColumn.ColumnName;
            // set additional column properties
            column.Caption = dataColumn.ColumnName;
            ASPxGridView1.Columns.Add(column);
        }
    }
}

Visual Basic
Imports Microsoft.VisualBasic
Imports System
Imports System.Data
Imports System.Configuration
Imports System.Collections
Imports System.Web
Imports System.Web.Security
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.WebControls.WebParts
Imports System.Web.UI.HtmlControls
Imports DevExpress.Web

Partial Public Class _Default
    Inherits System.Web.UI.Page
    Protected Sub ASPxGridView1_Load(ByVal sender As Object, ByVal e As EventArgs)
        ' set DataSource
        ASPxGridView1.DataSource = GetCurrentTable()
        ' create columns, if necessary
        EnsureColumns()
        ' call DataBind()
        ASPxGridView1.DataBind()
    End Sub

    Private Function GetCurrentTable() As DataTable
        If ASPxRadioButton1.Checked Then
            Return GetTable1()
        Else
            Return GetTable2()
        End If
    End Function

    Private Function GetTable1() As DataTable
        Dim dt As DataTable = CType(Session("Table1"), DataTable)
        If dt Is Nothing Then
            dt = New DataTable()
            dt.Columns.Add("ID1")
            dt.Columns.Add("Data1")
            For i As Integer = 0 To 4
                dt.Rows.Add(i, "row 1 " & i.ToString())
            Next i
            Session.Add("Table1", dt)
        End If
        Return dt
    End Function
    Private Function GetTable2() As DataTable
        Dim dt As DataTable = CType(Session("Table2"), DataTable)
        If dt Is Nothing Then
            dt = New DataTable()
            dt.Columns.Add("ID2")
            dt.Columns.Add("Data2")
            For i As Integer = 0 To 9
                dt.Rows.Add(i, "row 2 " & i.ToString())
            Next i
            Session.Add("Table2", dt)
        End If
        Return dt
    End Function

    Private Sub EnsureColumns()
        If ASPxGridView1.Columns.Count = 0 Then
            ReCreateColumns()
        Else
            Dim table As DataTable = GetCurrentTable()
            ' if the grid has other columns than the assigned data source, 
            ' recreate columns
            If ASPxGridView1.Columns(table.Columns(0).ColumnName) Is Nothing Then
                ReCreateColumns()
            End If
        End If
    End Sub

    Private Sub ReCreateColumns()
        ASPxGridView1.Columns.Clear()

        Dim table As DataTable = GetCurrentTable()
        For Each dataColumn As DataColumn In table.Columns
            Dim column As New GridViewDataTextColumn()
            column.FieldName = dataColumn.ColumnName
            ' set additional column properties
            column.Caption = dataColumn.ColumnName
            ASPxGridView1.Columns.Add(column)
        Next dataColumn
    End Sub
End Class