小弟菜一枚，求教执行带返回值的查询存储过程（在线等）

Question

界面存储c#

Answer 1

try
             {  
                 cmd = new SqlCommand("p_selectTimu2", conn);
                 cmd.CommandType = CommandType.StoredProcedure;//执行存储过程
                SqlParameter Id = new SqlParameter("@id", SqlDbType.Int);                 Id.Value = selectItem;  //给封装后的值赋值
                cmd.Parameters.Clear(); //清空原有的参数集合
                cmd.Parameters.Add(Id).Direction = ParameterDirection.ReturnValue; ;//将参数传递到数据库中去,返回值                conn.Open();
                 cmd.ExecuteNonQuery();  //执行一遍，
                //reader = cmd.ExecuteReader();   //再执行一遍
                //cboSubobject.Text = cmd.Parameters["@id"].Value.ToString();
                 DataSet ds = new DataSet();
                 //da.Fill(ds, "o");
  using (SqlDataAdapter sqlDA = new SqlDataAdapter(cmd))
                {
                    sqlDA.FillLoadOption = LoadOption.OverwriteChanges;
                    sqlDA.Fill(ds, "o");
                    DataTable dt = ds.Tables["o"];
 if (dt = null) return;
                 foreach (DataRow row in dt.Rows)
                 {
                     txTimu.Text = row["Timu"] + "";
                     txtA.Text = row["An"] + "";
                     txtB.Text = row["Bn"] + "";
                     txtC.Text = row["Cn"] + "";
                     txtD.Text = row["Dn"] + "";
                     cboType.Text = row["type"] + "";
                     cboFen.Text = row["score"] + "";
                     cboSubobject.Text = row["academicsName"] + "";
                 }
                }
                 
             }
             catch (Exception) { }
             finally
             {
                 conn.Close();
             }

Answer 2

 if (dt = null) return; 
应为  
if (dt == null) 
{
 conn.Close();
return;
}