How to Scroll a Form When VB Forms Are Limited to Screen Size

• Professional and Enterprise Editions of Microsoft Visual Basic, 16-bit only, for Windows, version 4.0
• Standard and Professional Editions of Microsoft Visual Basic for Windows, version 3.0

SUMMARY

A Visual Basic form cannot be sized larger than the screen. This article explains how to scroll the contents of a form to enlarge the usable area of a form.

The sample program below works by scrolling a picture box control which is larger than the form and contains attached controls. When the picture box scrolls, all the attached controls scroll together.

MORE INFORMATION

Step-by-Step Example

NOTE: This technique will not work on any version of Windows NT if any of the Visual Basic lightweight controls (for example, Label Control) are children of the scrolling control and positioned outside of the screen's viewing area. This is due to the way that Windows NT handles drawing to nonlogical areas of the screen. To work around the problem, do not use lightweight controls as children of the scrolling control.

1. Start a new project in Visual Basic. Form1 is created by default.

2. Add a horizontal scroll bar control and a vertical scroll bar control to Form1. (The size doesn't matter because the program automatically sizes the scroll bars in the Form Resize event code.)

3. Add a picture box control to Form1. Draw a text box control inside the upper-left corner of the picture box such that when the picture box moves, the text box moves with it.

   Select the Text1 box and press the F4 key to display the Properties window. Set the Text1 Index property to 0, which is required at design time to make an array of text controls.

   You can also enhance this sample program by placing more controls into the picture box. When the picture box scrolls, all the controls scroll.

4. Add the following code to the Form Load event:

         Sub Form_Load ()
            ' Make the picture box bigger than the form:
            Picture1.Move 0, 0, 1.4 * ScaleWidth, 1.2 * ScaleHeight ' Place
               some sample controls in the picture box:
            Dim i As Integer
            For i = 1 To 20
               Load Text1(i)
               Text1(i).Visible = True
               Text1(i).Left = i * Picture1.Height / 20
               Text1(i).Top = Text1(i).Left
            Next
         End Sub
   
   

5. Add the following code to the Form Resize event:

         Sub Form_Resize ()
            ' Position the scroll bars:
            hscroll1.Left = 0
            vscroll1.Top = 0
            If Picture1.Width > scalewidth Then
               hscroll1.Top = ScaleHeight - hscroll1.Height
            Else
               hscroll1.Top = ScaleHeight
            End If
            If Picture1.Height > hscroll1.Top Then
               vscroll1.Left = scalewidth - vscroll1.Width
               If Picture1.Width > vscroll1.Left Then
                  hscroll1.Top = ScaleHeight - hscroll1.Height
               End If
            Else
               vscroll1.Left = scalewidth
            End If
            hscroll1.Width = scalewidth
            If hscroll1.Top > 0 then vscroll1.Height=hscroll1.Top
            ' Set the scroll bar ranges
            hscroll1.Max = Picture1.Width - vscroll1.Left
            vscroll1.Max = Picture1.Height - hscroll1.Top
            hscroll1.SmallChange = Abs(hscroll1.Max \ 16) + 1
            hscroll1.LargeChange = Abs(hscroll1.Max \ 4) + 1
            vscroll1.SmallChange = Abs(vscroll1.Max \ 16) + 1
            vscroll1.LargeChange = Abs(vscroll1.Max \ 4) + 1
            hscroll1.ZOrder 0
            vscroll1.ZOrder 0
         End Sub
   
   

6. Add the following code to the HScroll1 Change event:

         Sub HScroll1_Change ()
            Picture1.Left = -HScroll1.Value
         End Sub
   
   

7. Add the following code to the VScroll1 Change event:

         Sub VScroll1_Change ()
            Picture1.Top = -VScroll1.Value
         End Sub
   
   

8. Start the program (or press the F5 key). Click the scroll bars to scroll the form. Close the form to end the program.