Grid View for ASP.NET Web Forms - How to get column values of multiple selected rows.

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 System.Collections.Generic;
using DevExpress.Web;

namespace GetSelectedValuesAllColumns {
    public partial class _Default : System.Web.UI.Page {
        protected void Page_Init(object sender, EventArgs e) {
            ASPxGridView1.DataSource = GetData();
            ASPxGridView1.KeyFieldName = "ID";
            ASPxGridView1.SettingsBehavior.AllowSelectByRowClick = true;
            ASPxGridView1.DataBind();

            if(!IsPostBack && !IsCallback) {
                ASPxGridView1.Columns[ASPxGridView1.KeyFieldName].Visible = false;
            }
        }

        private DataTable GetData() {
            DataTable table = new DataTable();
            table.Columns.Add("ID", typeof(int));
            table.Columns.Add("Name", typeof(string));
            table.Columns.Add("Date", typeof(DateTime));
            table.Columns.Add("IsActive", typeof(bool));
            for(int i = 0; i < 10; i++) {
                table.Rows.Add(i, "Item " + i.ToString(), DateTime.Now.AddDays(i), i % 2 == 0);
            }
            return table;
        }
        protected void ASPxButton1_Click(object sender, EventArgs e) {
            GetSelectedValues();
            PrintSelectedValues();
        }

        
        List<object> selectedValues;

        private void GetSelectedValues() {
            List<string> fieldNames = new List<string>();
            foreach(GridViewColumn column in ASPxGridView1.Columns)
                if(column is GridViewDataColumn)
                    fieldNames.Add(((GridViewDataColumn)column).FieldName);
            selectedValues = ASPxGridView1.GetSelectedFieldValues(fieldNames.ToArray());
        }

        private void PrintSelectedValues() {
            if(selectedValues == null) return;
            string result = "";
            foreach(object[] item in selectedValues) {
                foreach(object value in item) {
                   result += string.Format("{0}&nbsp;&nbsp;&nbsp;&nbsp;", value);
                }
                result += "</br>";
            }
            Literal1.Text = result;
        }
    }
}

Visual Basic
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 System.Collections.Generic
Imports DevExpress.Web

Namespace GetSelectedValuesAllColumns
    Partial Public Class _Default
        Inherits System.Web.UI.Page

        Protected Sub Page_Init(ByVal sender As Object, ByVal e As EventArgs)
            ASPxGridView1.DataSource = GetData()
            ASPxGridView1.KeyFieldName = "ID"
            ASPxGridView1.SettingsBehavior.AllowSelectByRowClick = True
            ASPxGridView1.DataBind()

            If Not IsPostBack AndAlso Not IsCallback Then
                ASPxGridView1.Columns(ASPxGridView1.KeyFieldName).Visible = False
            End If
        End Sub

        Private Function GetData() As DataTable
            Dim table As New DataTable()
            table.Columns.Add("ID", GetType(Integer))
            table.Columns.Add("Name", GetType(String))
            table.Columns.Add("Date", GetType(DateTime))
            table.Columns.Add("IsActive", GetType(Boolean))
            For i As Integer = 0 To 9
                table.Rows.Add(i, "Item " & i.ToString(), DateTime.Now.AddDays(i), i Mod 2 = 0)
            Next i
            Return table
        End Function
        Protected Sub ASPxButton1_Click(ByVal sender As Object, ByVal e As EventArgs)
            GetSelectedValues()
            PrintSelectedValues()
        End Sub


        Private selectedValues As List(Of Object)

        Private Sub GetSelectedValues()
            Dim fieldNames As New List(Of String)()
            For Each column As GridViewColumn In ASPxGridView1.Columns
                If TypeOf column Is GridViewDataColumn Then
                    fieldNames.Add(CType(column, GridViewDataColumn).FieldName)
                End If
            Next column
            selectedValues = ASPxGridView1.GetSelectedFieldValues(fieldNames.ToArray())
        End Sub

        Private Sub PrintSelectedValues()
            If selectedValues Is Nothing Then
                Return
            End If
            Dim result As String = ""
            For Each item As Object() In selectedValues
                For Each value As Object In item
                   result &= String.Format("{0}    ", value)
                Next value
                result &= "</br>"
            Next item
            Literal1.Text = result
        End Sub
    End Class
End Namespace