mysql while(datareader.Read()) doesn't execute

Question

for some reason the following C# code doesn't work:

          int id = 1293842;
        connect.Open();
        string getInfoQuery = "SELECT * FROM table WHERE id = @idpara";
        MySqlCommand getInfo = new MySqlCommand(getInfoQuery, connect);
        getInfo.Parameters.AddWithValue("@idpara", id);
      
     
        string username = "test";
  
     
        MySqlDataReader dataGet = getInfo.ExecuteReader();
        while (dataGet.Read()) {
         
            username = dataGet.GetString("username");
           
        }
        MessageBox.Show(username);

The MessageBox doesn't display the username I look for, but 'test', the value I used for the declaration of my string.

Help is appreciated!

Have you checked that your table has a username with the id you're using? Have you also checked that the reader is executing successfully? I don't see any exception handling. — greenjaed, Feb 02 '21 at 22:29
@greenjaed Yes, that is checked before this part of the code. — Loli, Feb 02 '21 at 22:42
Put a breakpoint inside the while loop. If code doesn't stop on the breakpoint then you don't have a record with that id (or you are looking at the wrong database) If it stops then the username is 'test' — Steve, Feb 02 '21 at 22:46
Aside: please see [C# Data Connections Best Practice?](https://stackoverflow.com/questions/17552829/c-sharp-data-connections-best-practice) — Charlieface, Feb 02 '21 at 22:52
The record that you think is there isn't. Most common cause - you are connected to the wrong database. — mjwills, Feb 02 '21 at 22:57
I was thinking about this syntax `dataGet["username"]` and `dataGet.GetString(1);` — Cyrille Con Morales, Feb 03 '21 at 06:50

score 0 · Answer 1 · answered Feb 03 '21 at 05:03

MySqlDataReader.GetString Method (Int32)


public override string GetString(
    int i
)

**Parameters i**
Type: System.Int32
The zero-based column ordinal.

Return Value
Type: String
The value of the specified column.

https://dev.mysql.com/doc/dev/connector-net/8.0/html/M_MySql_Data_MySqlClient_MySqlDataReader_GetString.htm

score 0 · Answer 2 · answered Feb 03 '21 at 10:07

0

So, the solution was:

SELECT * FROM table WHERE id=@idpara

instead of

SELECT * FROM table WHERE id = @idpara

answered Feb 03 '21 at 10:07

Loli

1
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mysql while(datareader.Read()) doesn't execute

2 Answers2