Databind() problem in asp.net

Hi guys, just wondering if anyone can help me to solve this issue. Below is my code, i take data from database into dataset and then to datagrid, then bind it. after changes made by a dropdownlist, it will lead to the same function which is take data from database into dataset and datagrid and bind again. If i do this, the dropdownlist will be refresh everytime i bind it and the cause is i can’t make the text selected by the user in the dropdownlist stay in the textfield, it will always go default as it is refreshed. Please help me. anyone!

This is the code that i used to take data from database and binding operation:


protected void BindIndicator(string selectedValue)
        {

            string sqlCommand = SqlStatement(selectedValue);
            string IndicatorQuery = "";

            if (GetOracleConnection())
            {
                try
                {
                    OracleCommand cmd = new OracleCommand(sqlCommand, connection);
                    cmd.CommandType = CommandType.Text;
                    OracleDataAdapter da = new OracleDataAdapter(cmd);
                    DataSet dataSet = new DataSet();
                    da.Fill(dataSet);
                    int RowCount = ((dataSet.Tables[0].Rows.Count) - 1);
                    DataSet dSet = new DataSet();

                    for (int i = 0; i <= RowCount; i++)
                    {
                        IndicatorQuery = dataSet.Tables[0].Rows[i][0].ToString();
                        OracleCommand command = new OracleCommand(IndicatorQuery, connection);
                        command.CommandType = CommandType.Text;
                        OracleDataAdapter dataAdapter = new OracleDataAdapter(command);
                        dataAdapter.Fill(dSet);
                        dataGridView.DataSource = dSet;
                        dataGridView.DataBind();
                    }

                }
                catch (Exception ex)
                {
                    MessageBoxShow(this, ex.Message.ToString());
                }
            }
        }

and this is code when user select from dropdownlist


 protected void DropDownList1_SelectedIndexChanged(object sender, EventArgs e)
        {
           DropDownList ddlIndicator = (DropDownList)dataGridView.HeaderRow.FindControl("ddlIndicator");
           try
           {
               string selectedValue = ddlIndicator.SelectedValue.ToString();
               int selectedIndex = ddlIndicator.SelectedIndex;

               if (selectedValue != "" && selectedValue != "default")
               {
                   BindIndicator(selectedValue);
               }

               ddlIndicator.SelectedIndex = selectedIndex;
           }
           catch (Exception ex)
           {
               MessageBoxShow(this, ex.Message.ToString());
           }

        }