Command problem

Peter_1985 2,526

Hi,
I see that UserID0.Value is with the proper value 18 and there is the existing record with INT column user_id having the value 18. But it is not getting the record by the following command. Why?

            SqlCommand cmd = new SqlCommand("SELECT top 1 ... FROM [user_master] where [user_id]=@par_id", conn);

            if (UserID0.Value != null)
            {
                cmd.Parameters.Add("@par_id", SqlDbType.Int).Value = Convert.ToInt32(UserID0.Value);
            }

Viorel 112.5K Reputation points

2022-05-31T05:26:34.973+00:00

Maybe there is a problem in the rest of the code?
Peter_1985 2,526 Reputation points

2022-05-31T06:02:13.863+00:00
Hi,
I further have the codes like

SqlDataReader reader; reader = cmd.ExecuteReader(); if (reader.HasRows) { reader.Read(); ...

to retrieve the record. But it is not getting the record expectedly.
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T06:14:54.217+00:00

@Peter_1985 , Does it return true or false for reader.HasRows property? If you execute the above query with proper value 18 in the ssms, Could you see some records in the ssms?
Peter_1985 2,526 Reputation points

2022-05-31T06:21:03.247+00:00

The same query is returning the record, with the value 18, within SSMS. I do not know it does not get into the part (of "if (reader.HasRows)").
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T06:33:17.73+00:00

@Peter_1985 , you could write the code bool t=reader.HasRows;, to check the value of reader.HasRows.
Peter_1985 2,526 Reputation points

2022-05-31T06:42:56.127+00:00
Yes, I put the code below. But it does not get into if part.

bool t = reader.HasRows; if (t) { reader.Read();
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T06:46:38.813+00:00

@Peter_1985 , you could output the t value by using the code Console.WriteLine(t); or MessageBox.Show(t.ToString());.
Viorel 112.5K Reputation points

2022-05-31T07:16:53.603+00:00

Do you get a row if you temporarily remove the WHERE part?
Peter_1985 2,526 Reputation points

2022-05-31T07:22:19.047+00:00
I cannot capture the value by the way below. I tried to remove where clause of the query but no help.

Page.ClientScript.RegisterStartupScript(this.GetType(), "alert", "ShowMessage('0531aa " + t.ToString() + "');", true);
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T07:47:56.01+00:00

@Peter_1985 , you could set a breakpoint for the code and put mouse on the variable of t after you executing the code.
Peter_1985 2,526 Reputation points

2022-05-31T08:49:12.313+00:00

When debugging it, how to see the value of t of the following line?

bool t = reader.HasRows;
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T08:51:21.43+00:00

@Peter_1985 , you could put mouse put on the t variable. Also, you could choose t then right click choose Add watch to check the value of t.
Peter_1985 2,526 Reputation points

2022-05-31T08:53:23.93+00:00

Hi,
What to press below?
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T08:59:51.317+00:00

@Peter_1985 , Please ensure that your program is running then you could press F10 to execute the code statement by statement.

Like the following:
Peter_1985 2,526 Reputation points

2022-05-31T09:04:16.013+00:00

Can I know what you press on t, on the line "bool t ..."?
Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T09:07:57.41+00:00

@ Jackson1990-7147, just use mouse to choose t without pressing something.
Karen Payne MVP 35,036 Reputation points

2022-05-31T19:55:07.37+00:00

What is returned when hard-coding the SQL ?

SELECT top 1 ... FROM [user_master] where [user_id]=18

2 answers

Peter_1985 2,526 Reputation points

2022-05-31T09:21:34.88+00:00

I hover the mouse on t below, and do not see the same effect like you.
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Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-05-31T09:27:17.59+00:00

@Peter_1985 , Please ensure that your app is running then please use F10 to execute your program. By the way, what is your current project?

Peter_1985 2,526 Reputation points

2022-05-31T09:44:40.067+00:00

I press the following button to start testing the project. I am using VS 2019.

Peter_1985 2,526 Reputation points

2022-05-31T09:58:05.17+00:00

Is the following the reason of the issue, but "reader" was declared already?

Jack J Jun 24,296 Reputation points Microsoft Vendor

2022-06-01T01:41:50.007+00:00

@Peter_1985 , based on your picture, I guess that your app is a asp.net webform app, right?

Peter_1985 2,526 Reputation points

2022-06-01T02:53:07.59+00:00

Yes, correct

Peter_1985 2,526 Reputation points

2022-06-01T04:59:24.243+00:00

Thanks to all.
How to mark this thread as resolved?

Lan Huang-MSFT 25,711 Reputation points Microsoft Vendor

2022-06-01T06:43:15.927+00:00

Hi @Peter_1985 ,
You can post your workaround as an answer and click Accept Answer

Peter_1985 2,526 Reputation points

2022-06-01T06:50:36.697+00:00

No way to mark one of the replies in above, as the answer?

Lan Huang-MSFT 25,711 Reputation points Microsoft Vendor

2022-06-01T06:59:37.857+00:00

Hi @Peter_1985 ,
You can click "More" then click "convert to answer", and finally click Accept Answer.
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bet365samcom 1 Reputation point

2022-06-02T17:12:39.967+00:00

thanks a lot!
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