想請教一下
如下的判斷，
我是想做如輸入相同值就跳重複值訊息，
有讀到資料就帶資料進來，如果沒有符合就跳找不到品號，

現在這樣是找到資料還是會跳重複值的訊息

   protected void t_TextChanged(object sender, EventArgs e)
        {
            string ConnectionString=System.Web.Configuration.WebConfigurationManager.ConnectionStrings["readerConnectionString"].ConnectionString;
            SqlConnection conn = new SqlConnection(ConnectionString);
            conn.Open();

            DataTable dt = (DataTable)ViewState["Curtbl"];
   
            foreach (GridViewRow rw in this.gv.Rows)
            {
                TextBox tTextBox1 = (TextBox)rw.FindControl("TextBox1");
                TextBox tTextBox2 = (TextBox)rw.FindControl("TextBox2");
                TextBox tTextBox3 = (TextBox)rw.FindControl("TextBox3");
                TextBox tTextBox4 = (TextBox)rw.FindControl("TextBox4");

                string m_Text = tTextBox1.Text.Trim();
                bool m_IsExist = false;
                foreach (DataRow dr in dt.Rows)
                {
                    if (m_Text == dr[1].ToString().Trim())
                    {
                        m_IsExist = true;
                        break;
                    }
                }

                if (!m_IsExist)
                {
                try
                {
                        SqlCommand command = new SqlCommand("select MB001,MB002,MB003,MB064 from INVMB where MB001='" + tTextBox1.Text + "'", conn);
                        //conn.Open();
                        SqlDataReader reader1;
                        reader1 = command.ExecuteReader();

                        if (reader1.Read() && tTextBox1.Text != "")
                        {
                            tTextBox2.Text = reader1["MB002"].ToString();
                            tTextBox3.Text = reader1["MB003"].ToString();
                            string r_qty = reader1["MB064"].ToString();
                            double a = Convert.ToDouble(r_qty.ToString());
                            tTextBox4.Text = a.ToString();
                         

                        }
                        else 
                        {
                            String TransferPage;
                            TransferPage = "<script>alert('找不到該品號！')</script>";
                            ScriptManager.RegisterStartupScript(Page, Page.GetType(), "temp", TransferPage, false);
                            tTextBox1.Text="";

                        }
           reader1.Close();

                }
                catch
                {


                }

                }
                else
                {
                    //tTextBox1.Text = "";
                    String TransferPage1;
                    TransferPage1 = "<script>alert('重複值！')</script>";
                    ScriptManager.RegisterStartupScript(Page, Page.GetType(), "temp", TransferPage1, false);
                    //this.lblErrorMessage.Visible = true;
                }
            }
        }