winform for循环

C# code

       for (int i = 0; i < dgv_Data2.Rows.Count - 1; i++)            {                for (int j = 1; j < dgv_Data2.Rows.Count - 1; j++)                {                    if ((i + j) <= dgv_Data2.Rows.Count)                    {                        string value1 = Convert.ToString(dgv_Data2.Rows[i].Cells[2].Value);                        string value2 = Convert.ToString(dgv_Data2.Rows[i + j].Cells[2].Value);                        if (value1 == value2)                        {                            MessageBox.Show("此货物已存在！");                        }                       else                        {                            string name = dgv_Data2.Rows[i].Cells[2].Value.ToString();                            string sql = "select * from MIS_MaterielRegiser where MR_Name='" + name + "'";                                                   ocmd = new OleDbCommand(sql, ocnn);                            OleDbDataReader reader = ocmd.ExecuteReader();                            reader.Read();                            dgv_Data2.Rows[i].Cells[1].Value = reader["MR_Number"].ToString();                            dgv_Data2.Rows[i].Cells[3].Value = reader["MR_Model"].ToString();                            dgv_Data2.Rows[i].Cells[4].Value = reader["MR_Unit"].ToString();                        }                    }                                     }            }

dgv_Data2是datagridview 我是想判断单元格的内容是否跟前面输入的相同，不过这样写在第一行和第二行输入值后。相应的单元不会自动填充值。但是如果第三行输入值后就会全部自动填好！我不知道逻辑错在哪，请大家指正！

[解决办法]

C# code

int length = dgv_Data2.Rows.Count - 1; for (int i = 0; i <length ; i++)            {                for (int j = length; j > i; j--)　　         {                        string value1 = Convert.ToString(dgv_Data2.Rows[j].Cells[2].Value);                       string value2 = Convert.ToString(dgv_Data2.Rows[j-1].Cells[2].Value);if (value1 == value2)                        {                            MessageBox.Show("此货物已存在！");                        }                       else                        {                            string name = dgv_Data2.Rows[i].Cells[2].Value.ToString();                            string sql = "select * from MIS_MaterielRegiser where MR_Name='" + name + "'";                                                   ocmd = new OleDbCommand(sql, ocnn);                            OleDbDataReader reader = ocmd.ExecuteReader();                            reader.Read();                            dgv_Data2.Rows[i].Cells[1].Value = reader["MR_Number"].ToString();                            dgv_Data2.Rows[i].Cells[3].Value = reader["MR_Model"].ToString();                            dgv_Data2.Rows[i].Cells[4].Value = reader["MR_Unit"].ToString();                        }               ｝            ｝
[解决办法]
你是要比较所有的行么？
for (int j = 0; j < dgv_Data2.Rows.Count - 1; j++)
               {
                   if (i!=j)
                   {
                      string value1 = Convert.ToString(dgv_Data2.Rows[i].Cells[2].Value);
                      string value2 = Convert.ToString(dgv_Data2.Rows[j].Cells[2].Value);