Edit in DropDown

private void UpdateAssignment()
{
string FileDirectory = Server.MapPath("Database/admin.mdb");
OleDbConnection ocon = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + FileDirectory.ToString() + "");
try
{
ocon.Open();
string id = Request.QueryString["id"].ToString();
// SELECT Project_master.Project_name,Project_master.Project_status, , User_master.User_name, Project_assignment.* FROM (Project_assignment INNER JOIN User_master ON Project_assignment.User_id = User_master.User_id) INNER JOIN Project_master ON Project_assignment.Project_id = Project_master.Project_id;"
// string str = "select * from Project_assignment where ProjAssign_id=" + id + "";
string str = "SELECT Project_master.Project_name,Project_master.Project_id,User_master.User_id,Project_assignment.ProiAssig_Allolet_hours as Allotted,Project_assignment.ProjAssig_opening_hours as Projecthours,Project_assignment.ProjAssig_module as Projectmodule,User_master.User_name,Project_assignment.ProjAssign_id, Project_assignment.* FROM (Project_assignment INNER JOIN User_master ON Project_assignment.User_id = User_master.User_id) INNER JOIN Project_master ON Project_assignment.Project_id = Project_master.Project_id where ProjAssign_id=" + id + "";

OleDbCommand ocom = new OleDbCommand(str, ocon);
OleDbDataReader updateReader = ocom.ExecuteReader();
if (updateReader.HasRows)
{
updateReader.Read();
//Ddprojectid,DDuserid,txtopeninghours,txtmodule
// txtProName.Text = updateReader["Project_name"].ToString();
// txtEmoName.Text = updateReader["User_name"].ToString();
txtopeninghours.Text = updateReader["Projecthours"].ToString();
txtAlote.Text = updateReader["Allotted"].ToString();
Session["ProjectId"] = updateReader["Project_master.Project_id"].ToString();
txtmodule.Text = updateReader["Projectmodule"].ToString();
// DDteamleader.SelectedIndex = DDteamleader.Items.IndexOf(DDteamleader.Items.FindByValue(updateReader["User_master.User_id"].ToString()));
DDProName.SelectedIndex = DDProName.Items.IndexOf(DDProName.Items.FindByValue(updateReader["Project_master.Project_id"].ToString()));
DDEmpName.SelectedIndex = DDEmpName.Items.IndexOf(DDEmpName.Items.FindByValue(updateReader["User_master.User_id"].ToString())); }
}
catch (Exception ex)
{
Response.Write(ex.Message.ToString());
}

}