Hi Tarun,
I use a different method. Please see below if that helps;
using System.Data;
using System.Data.SqlClient;
SqlConnection con = new SqlConnection();
SqlCommand cmd = new SqlCommand();
SqlDataAdapter adap = new SqlDataAdapter();
DataTable dt = new DataTable();
con.ConnectionString = "";
con.Open();
cmd = con.CreateCommand();
cmd.CommandType = CommandType.StoredProcedure;
cmd.CommandText = "";
cmd.Parameters.AddWithValue("ParamName1", "ParamValue1");
cmd.Parameters.AddWithValue("ParamName2", "ParamValue2");
cmd.Parameters.AddWithValue("ParamName3", "ParamValue3");
cmd.CommandTimeout = 10000;
adap.SelectCommand = cmd;
adap.Fill(dt);
con.Close();
this.comboBox1.DataSource = dt;
this.comboBox1.DisplayMember = "FieldToDisplayAsTextItemInComboBox";
this.comboBox1.ValueMember = "FieldToBeUsedAsValueItem";
this.txtbox1.text = dt.Rows[0]["FieldName"].ToString();
Hope this helps.
Please mark the answer if appropriate.
Happy coding..!!
--Nayan