do While problem !

Code:

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Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        On Error Resume Next
        Dim sql As String
        ListBox1.Items.Clear()
        ListBox2.Items.Clear()


        Select Case SifraDokum
            Case 1, 2, 3
                sql = "kupac = True"
            Case 4
                sql = "dobav = True"

            Case Else
                MsgBox("Morate odrediti vrstu dokumenta!", MsgBoxStyle.OkOnly)
                Exit Sub
        End Select

        If TextBox1.Text <> "" Then
            Select Case Len(TextBox1.Text)
                Case 1
                    sql = "SELECT sifra, naziv_dob FROM kupac " _
                      & " WHERE " & sql & " AND naziv_dob Like '" & TextBox1.Text & "%'" _
                      & " ORDER BY naziv_dob"
                Case 2, 3, 4, 5, 6, 7, 8
                    sql = "SELECT sifra, naziv_dob FROM kupac " _
                        & " WHERE " & sql & " AND naziv_dob Like '%" & TextBox1.Text & "%'" _
                        & " ORDER BY naziv_dob"
            End Select
            'rsProdaja.open(sql, cnProdaja, adOpenForwardOnly, adLockReadOnly)

         
            'cnProdaja = New Data.SqlServerCe.SqlCeConnection("Data Source =\Program Files\POCKET_PC\pocket.sdf;")
            Dim naredba As New System.Data.SqlServerCe.SqlCeCommand(sql, cnProdaja)
            'cnProdaja.Open()
            Dim dr4 As System.Data.SqlServerCe.SqlCeDataReader = naredba.ExecuteReader
            'Dim dr4 As System.Data.SqlServerCe.SqlCeDataReader
            If dr4.Read <> 0 Then
                'Do While dr4.Read

                Do While dr4.Read
                    ListBox2.Items.Add(dr4("naziv_dob").ToString)
                    ListBox1.Items.Add(dr4("sifra").ToString)
                    'rsProdaja.movenext()

                Loop
            End If
            dr4.Close()
        End If
        TextBox1.Text = ""
    End Sub

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Bolded is problem,when I start program and when i put brakepoint
Do While dr4.Read
program just keep running in

Code:

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Do While dr4.Read
listBox2.Items.Add(dr4("naziv_dob").ToString)
ListBox1.Items.Add(dr4("sifra").ToString)
 'rsProdaja.movenext()

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and never to get to End if.
I database I have only one naziv_dob and one sifra .Where is problem here?

just a note:

i think whenever you call dr.Read, it actually reads one record then point to the next record, if any. if i am right, your IF statement has already read the first record, and your do while is now processing the second record, if any.

i haven't tried your code yet, but i think it would be cleaner if it would look like so (remove the IF-ENDIF)

Code:

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While dr4.Read
      ListBox2.Items.Add(dr4("naziv_dob").ToString)
      ListBox1.Items.Add(dr4("sifra").ToString)
End While

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try it and post back if anything....cheers!


elf

It same problem again !

i see.

i noticed u have On Error Resume Next, which i think is almost never advisable. remove that, and resolve any error that may be thrown by the app.

i will try your code when i find the time.


cheers!

This line:

If dr4.Read <> 0 Then

should be:

If dr4.HasRows Then

otherwise you will be skipping over the first row. You say that you only have one row, so the do loop actually should never happen, because the If statement should have moved the pointer past that one row. There are a couple of things that might have happened at that point, one of which would be an exception, but with On Error Resume Next, you may have gotten frozen into a perpetual loop, since the Next statement might have sent you right around the loop forever.

I would guess that the entire problem was ultimately the If statement, and fixing that could very well solve your problem, but that On Error Resume Next will cause you terrible problems whenever you use it. Basically, every statement could throw an exception, and you'd just keep on going. The actual behavior of the program would become nearly random. Structured exception handling (the Try....Catch block) is a vastly superior way to handle errors, partly for that reason. I agree that you should be using exception handling whenever you work with a database, but never On Error Resume Next.