code for previous comand button

[mustakbal]

This has to be very simple but I can't get it right and I'm getting frustrated with it. My code for the Next button works fine while using "index1" for lowerlimit and "index2" for the upperlimit and it goes like this :

If index1 < index2 Then
               index1 = index1 + 1
          Else
             MsgBox "This is the last record of the data"
           End If

but I can't get anything to work for the Previous command button so it stops at the lowerlimit and not keep going til the beginning of the file. I don't know if the simplest way to do this is with a For loop or If statement or Do While....
So I am all ears ..
Thanks in advance

[Trent]

This has to be very simple but I can't get it right and I'm getting frustrated with it. My code for the Next button works fine while using "index1" for lowerlimit and "index2" for the upperlimit and it goes like this :

If index1 < index2 Then
               index1 = index1 + 1
          Else
             MsgBox "This is the last record of the data"
           End If

but I can't get anything to work for the Previous command button so it stops at the lowerlimit and not keep going til the beginning of the file. I don't know if the simplest way to do this is with a For loop or If statement or Do While....
So I am all ears ..
Thanks in advance

You are changing the lowerlimit (index1) when you click the Next button.

Try this for the Next Button

If index < index2 Then
               index = index + 1
          Else
             MsgBox "This is the last record of the data"
           End If

And this for the Previous Button

If index >= index1 Then
                index = index - 1
            Else
                MsgBox "This is the first record of the data"
            End If

[mustakbal]

Trent, thanks for the help, but that didn't work either .As soon as I hit the previous button I get the message no matter what the position in the file is at that time. I was told that I need three variables for lowerlimit, upperlimit and currentposition -- but I still don't know if to use a for loop or do while or whatever. Any suggestions on that?

[Trent]

Trent, thanks for the help, but that didn't work either .As soon as I hit the previous button I get the message no matter what the position in the file is at that time. I was told that I need three variables for lowerlimit, upperlimit and currentposition -- but I still don't know if to use a for loop or do while or whatever. Any suggestions on that?

That's strange, it works for me except the first line of the code for the Previous Button should be:

If index > index1 Then

The only scenario I can think of that would continue to give you this problem is you are still using index1 in the code for the Next Button.

[Killer42]

Has index been set, anywhere?

Not having seen the rest of the code, I'm just guessing. But it looks as though we may have just introduced a new variable, index, without actually using it for anything. If that's so, then it will have the value zero, which will (presumably) always be less than index1.

[mustakbal]

That's true killer42, I got the error that index is not defined.The code for the Next and the Previous are :

 
  Private Sub CmdN_Click()
If index1 < index2 Then    ' I am using index2 as upperlimit
  index1 = index1 + 1
  Else
  MsgBox "This is the last record of the data"
    End If
lbltext1.Caption = line_value1(index1)

Private Sub CmdR_Click()
If index1 > index1 Then   ' index1 for lower limit
  index1 = index1 - 1
  Else
    MsgBox "This is the first record of the data"
    End If
lbltext1.Caption = line_value1(index1)
end

That's what I had at the very beginning. The Next button works fine but the Previous doesn't.
Trent I need to get back to index1 or I do not get anything displayed in lbltext1.

Maybe this eil make it easier to figure out the problem.
Thanks

[Killer42]

Sounds to me as though you need to use three variables rather than two. Which is what Trent was driving at, I'm sure. You see, at the moment you are treating index1 as both the current position and the lowest-allowed position. For example, you have a line which says "If index1 > index1". This is not possible. A variable cannot have a value different to itself.

What you need to do is use a separate variable (such as index) to indicate the current position within the range of index1 to index2. It then follows, of course, that index needs to be initialised to the current position (probably the same value as index1) before you start trying to adjust it through these two buttons. Most likely, index1 and index2 should never change during this processing.

[mustakbal]

So why doesn't Trent's code work even after I define "index " as long and then initialise it as = index1? Could you take a closer look at that because this is really driving me nuts.

It was simpler and it worked fine when I had "If Index1 > 1" and when it went back to the beginning of the record!

Did I do this the right way whe I "Dim index as long" and then
initialised " index = index1"? because it stil doesn't work.

[Killer42]

So why doesn't Trent's code work even after I define "index " as long and then initialise it as = index1? Could you take a closer look at that because this is really driving me nuts.

It was simpler and it worked fine when I had "If Index1 > 1" and when it went back to the beginning of the record!

Hey, if it works, it works. That's the name of the game, huh. Although generally speaking, if something doesn't work I feel it's probably a good idea to have some idea of why. But that's just me.

Did I do this the right way when I "Dim index as long" and then initialised " index = index1"? because it stil doesn't work.

My guess is that the problem is the scope of the variable. Without seeing the whole code it's hard to be sure. One question, though - where did you put that Dim?