C#中DataTable的使用，新手

C#中DataTable的使用，新手求助
本人是学习VC/MFC的，最近工作需要紧急修改一个C#程序，遇到各种不明白的地方，请大家指教。
先上代码：

                        for (int i = 0; i < count; i++)

                        {

                            DataRow dr;

                            dr = dt.NewRow();

                            dr[0] = true;//false

                            dr[1] = "0";

                            dr[2] = testfilelist.result[i].releaseDate;

                            dr[3] = testfilelist.result[i].latestVersion;

                            dr[4] = testfilelist.result[i].language;

                            dr[5] = "0";//FILESIZE

                            dr[6] = testfilelist.result[i].filename;   //文件名称

                            dr[7] = testfilelist.result[i].ftpPath;   //将文件名存这

                            dr[8] = testfilelist.result[i].downloadPath;

                            dt.Rows.Add(dr);

                            dt.AcceptChanges();

                        }

                        dtdistinct.Clear();

                        dtdistinct = dt.DefaultView.ToTable(true, new string[] { "Item", "SoftWare", "Date", "Index", "Filesize" });

                        DataColumn dataColumn1 = new DataColumn("Version", typeof(String));

                        dtdistinct.Columns.Add(dataColumn1);

                        dataColumn1 = new DataColumn("Language", typeof(String));

                        dtdistinct.Columns.Add(dataColumn1);

                        dataColumn1 = new DataColumn("filepath", typeof(String));

                        dtdistinct.Columns.Add(dataColumn1);

                        dataColumn1 = new DataColumn("downloadPath", typeof(String));

                        dtdistinct.Columns.Add(dataColumn1);

                        gridControl1.DataSource = dtdistinct;

                        //datarefreshgrid();

代码的运行结果就是生成一个表格，第一列是复选框，可勾选和不选
问题：
1.新增了一个按钮，要实现所有行的第一列的全选和全不选，我的代码如下，为什么没用？应该如何修改

            DataRow drOperate = dt.Rows[3];