pls help...... i want to select the "company name" from the dropdown but

dropdown.DataSource = GetData(); can be DataTable
dropdown.DataTextField = Name Column;
dropdown.DataValueField = Code Column;
dropdown.DataBind();

string company = dropdown.SelectedValue;

public void SaveDetails()
   {

       string str = "insert into temp (emp_code,emp_name,paswrd,domain_name,dpt_code,dpt_name,email,role,CompCode) values (@emp_code,@emp_name,@paswrd,@domain_name,@dpt_code,@dpt_name,@email,@role,@CompCode)";

           cmd = new SqlCommand(str, cn);

           cmd.Parameters.Add("@emp_code", SqlDbType.Int).Value = Convert.ToInt32(txtEmpCode.Text);
          // cmd.Parameters.Add("@emp_id", SqlDbType.Int).Value = 1;
           cmd.Parameters.Add("@emp_name", SqlDbType.VarChar).Value = txtEmpName.Text;
           cmd.Parameters.Add("@paswrd", SqlDbType.VarChar).Value = txtPwd.Text;
           cmd.Parameters.Add("@domain_name", SqlDbType.VarChar).Value = txtDomainName.Text;
           cmd.Parameters.Add("@dpt_code", SqlDbType.VarChar).Value = DDLDeptName.SelectedValue;
           cmd.Parameters.Add("@dpt_name", SqlDbType.VarChar).Value = DDLDeptName.Text;
           cmd.Parameters.Add("@email", SqlDbType.VarChar).Value = txtEmail.Text;
           cmd.Parameters.Add("@role", SqlDbType.Int).Value = Convert.ToInt32(DDLRole.SelectedIndex);
           cmd.Parameters.Add("@CompCode", SqlDbType.Int).Value = Convert.ToInt32(DDL_CompName.DataValueField="comp_code");    // this is the line where i m faceing the problem.... please tell me what to do here

it is givin the error as "Input string was not in a correct format."

       cmd.ExecuteNonQuery();

           LBLSuccessfullySaved.Text = "Data Saved Successfully";

           // calling the "blankall" method to remove all the entrys
           blankall();


   }