c# - 为什么我的 SQL 'INSERT' 语句执行了两次？

Question

我有以下插入命令，我需要获取范围标识以便稍后在应用程序中进行一些订单跟踪

SqlCommand cmd1 = new SqlCommand("INSERT INTO [pharm_OrderID](UserID, RequestType, CreateDate) values (@UserID, @RequestType, @CreateDate); Select SCOPE_IDENTITY();", conn1);
                    cmd1.CommandType = CommandType.Text;
                    conn1.Open();

                    string strUserID = txtEmpID.Text;
                    cmd1.Parameters.Add("@UserID", SqlDbType.NVarChar, 50);
                    cmd1.Parameters["@UserID"].Value = strUserID;

                    string strRequestType = ddlReturnType.SelectedValue;
                    cmd1.Parameters.Add("@RequestType", SqlDbType.NVarChar, 50);
                    cmd1.Parameters["@RequestType"].Value = strRequestType;

                    string strCreateDate = lblOrderAttemptTime.Text;
                    cmd1.Parameters.Add("@CreateDate", SqlDbType.NVarChar, 50);
                    cmd1.Parameters["@CreateDate"].Value = strCreateDate;

                    cmd1.ExecuteNonQuery();

                    string numScope = Convert.ToString(cmd1.ExecuteScalar());
                    lblOrderNum.Text = numScope;
                    cmd1.Dispose();
                    conn1.Close();
                    conn1.Dispose();

但是为什么要插入两次呢？

Answer 1

你正在执行它两次

1. cmd1.ExecuteNonQuery();
2. Convert.ToString(cmd1.ExecuteScalar());

你只需要 ExecuteScalar 来插入和选择:

decimal newID = (decimal) cmd1.ExecuteScalar();