using sql-aliases and the datareader

[akekrakbar]

Hello!
Im trying to do a simple login with databaseinteractivity. But when i try to get data wich doesn´t come from a column in the db but rather a function i get an error message. This is the code:

Sub klick_login(Src as object, E as EventArgs ) 
    
   Dim cn as new OLEDBConnection(dbPath) 
   Dim dr as OleDbDataReader 
   Dim strSql as String 

   strSql = "SELECT COUNT() as total FROM medlemmar WHERE anvandarnamn='" & txtAnvandarnamn.text & "' AND losenord='" & txtLosenord.text & "'" 

   Dim cm = New OLEDBCommand(strSQL, cn)

   cn.Open() 
    
   dr=Cm.ExecuteReader(CommandBehavior.CloseConnection) 

dr.read()


   cn.Close() 
   lblTest.text = dr("total") 

End Sub

This is the error message:

Exception Details: System.InvalidOperationException: No data exists for the row/column. 

Source Error: 


Line 26:    lblTest.text = dr("total")

What am I doing wrong?

 

[jn03]

Hi there,

You have to put the line:

lblTest.text = dr("total&quot

before:

cn.Close()

That's the way datareader works, it fetch data directly from the database. Once you close the datareader, the connection to the database is gone, so no data left, that's why you got the error.

Cheers.