Disable collapse of xtragrid group

using System; using System.Collections.Generic; using System.Drawing; using System.Windows.Forms; namespace Xtragrid { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void Form1_Load(object sender, EventArgs e) { List<Test> list = new List<Test>(); list.Add(new Test() { ID = 1, Name = "Patrick", Subject = "English", Score = 100M, TestDate = DateTime.Now.AddYears(0 - 1)}); list.Add(new Test() { ID = 2, Name = "Patrick", Subject = "Math", Score = 90M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 3, Name = "Patrick", Subject = "Chinese", Score = 80M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 4, Name = "Tom", Subject = "English", Score = 80M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 5, Name = "Tom", Subject = "Math", Score = 100M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 6, Name = "Tom", Subject = "Chinese", Score = 95.5M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 4, Name = "Mary", Subject = "English", Score = 80M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 5, Name = "Mary", Subject = "Math", Score = 100M, TestDate = DateTime.Now.AddYears(0 - 1) }); list.Add(new Test() { ID = 6, Name = "Mary", Subject = "Chinese", Score = 95.5M, TestDate = DateTime.Now.AddYears(0 - 1) }); gridControl1.DataSource = list; } private void gridView1_EndGrouping(object sender, EventArgs e) { gridView1.ExpandAllGroups(); } private void gridView1_GroupRowCollapsing(object sender, DevExpress.XtraGrid.Views.Base.RowAllowEventArgs e) { e.Allow = false; } private void gridView1_CustomDrawGroupRow(object sender, DevExpress.XtraGrid.Views.Base.RowObjectCustomDrawEventArgs e) { DevExpress.XtraGrid.Views.Grid.ViewInfo.GridGroupRowInfo info = e.Info as DevExpress.XtraGrid.Views.Grid.ViewInfo.GridGroupRowInfo; info.ButtonBounds = Rectangle.Empty; info.GroupText = " " + info.GroupText.TrimStart(); } } public class Test { public int ID { get; set; } public string Name { get; set; } public string Subject { get; set; } public DateTime TestDate { get; set; } public decimal Score { get; set; } } }