Set focus on the repeated row data while typing duplicate va

Question

I have a gridview in asp.net, in which I am inserting datas. When I insert repeated value then it will show item repeated. Now I need to show after the item repeated alert message the cursor will focus on the row value contain the item which is repeated. If my data table already contain code C1, then I again type c1 for insert then the cursor will focus on the row which contain c1 in gridview. Here is my code

 

 

protected void Button15_Click(object sender, EventArgs e)

{

    Control control = null;

    if (GridView1.FooterRow != null)

    {

        control = GridView1.FooterRow;

    }

    else

    {

        control = GridView1.Controls[0].Controls[0];

    }

    string Code = (control.FindControl("txtcode") as TextBox).Text;

   string txtno= (control.FindControl("txtno") as TextBox).Text;

    using (SqlConnection con = new SqlConnection("Data Source=XXXXXX;Initial Catalog=XXXXXX;User ID=XXXX;Password=XXXXXX"))

    {

        using (SqlCommand cmd = new SqlCommand())

        {

            DataTable dt = new DataTable();

            SqlDataAdapter da1;

            da1 = new SqlDataAdapter("select code from tbltmp where code='" + Code + "' ", con);

            da1.Fill(dt);

            if (dt.Rows.Count > 0)

            {

                ScriptManager.RegisterClientScriptBlock(this, this.GetType(),

                    "alertMessage",

                    "alert('Item Repeated');", true);

                (control.FindControl("txtcode") as TextBox).Focus();

            }              

            else

            {

                (control.FindControl("txtno") as TextBox).Focus();

            }

        }

    }

}