who to display data form sql db to datagridview having one fixed column name

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C#

SQL

i have a form which contains one textbox txtDistrict and a datagridview with one column clmTown

i want to display data from the db to the fixed column. the code i am using works but creates additional column to the exsisting one. how do i go about this

code

public void studentmoney()
        {
            SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
            string strConn = "Data Source=user-PC;Initial Catalog=MUCGPROJECT;User ID=sa;Password=mike";
            string strSQL = "select Town from districtnt where District = '" + txtDistrict.Text + "'";

            //conn.Open();
            SqlDataAdapter dataAdapter = new SqlDataAdapter(strSQL, strConn);
            SqlCommandBuilder commandBuilder = new SqlCommandBuilder(dataAdapter);
            // Populate a new data table and bind it to the BindingSource.
            DataTable table = new DataTable();
            table.Locale = System.Globalization.CultureInfo.InvariantCulture;
            dataAdapter.Fill(table);
            bindingSource1.DataSource = table;
            // you can make it grid readonly.
            dgvDistrict.ReadOnly = true;
            // finally bind the data to the grid
            dgvDistrict.DataSource = bindingSource1;
        }

itry using this but still does not works. please help me out

private void txtDistrict_SelectedIndexChanged(object sender, EventArgs e)
        {
            SqlConnection conn = new SqlConnection(ConfigurationSettings.AppSettings["ConnectionString"]);
            conn.ConnectionString = "Data Source=user-PC;Initial Catalog=MUCGPROJECT;User ID=sa;Password=mike";
         
            string sqlQuery = null;
            sqlQuery = "select * from DistrictnT where District = '" + txtDistrict.Text + "'";
            SqlCommand cmd = new SqlCommand();
            cmd.Connection = conn;
            cmd.CommandText = sqlQuery;
            cmd.CommandType = System.Data.CommandType.Text;
            conn.Open();
            SqlDataReader dr = cmd.ExecuteReader();
            try
            {
                while (dr.Read())
                {
                    dgvDistrict.Rows[dgvDistrict.Rows.Count - 1].Cells["clmTowns"].Value = dr[2].ToString();
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show("An error occurred: " + ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            finally
            {
                conn.Close();
            }
	}