Winforms – How to force vertical scrollbar always be visible from AutoScroll in WinForms

autoscrollscrollbarswinforms

Using VS2010 and .NET 4.0 with C# and WinForms:

I always want a Vertical Scrollbar to show for my panel as a disabled scrollbar (when it's not needed, and a enabled one when it can be used.

So it's like a hybrid AutoScroll. I've tried using VScrollBars but I can't figure out where to place them to make this work.

Essentially I've got a user control that acts as a "Document" of controls, its size changes so when using auto-scroll it works perfectly. The scrollbar appears when the usercontrol doesn't fit and the user can move it updown.

It's like a web browser essentially. However, redrawing controls takes a long time (it's forms with many fields and buttons etc within groups in a grid within a panel 😛

So anyhow, when autoscroll enables the vertical scrollbar, it takes a while to redraw the window. I'd like to ALWAYS show the vertical scrollbar as indicated above (with the enable/disable functionality).

If anyone has some help, i've read many posts on the subject of autoscroll, but noone has asked what I'm asking and I can't come up with a solution.

Best Answer

C# Version of competent_Tech's answer

using System.Runtime.InteropServices; 

public class MyUserControl : UserControl
{
    [DllImport("user32.dll")]
    [return: MarshalAs(UnmanagedType.Bool)]
    private static extern bool ShowScrollBar(IntPtr hWnd, int wBar, bool bShow);

    private enum ScrollBarDirection
    {
        SB_HORZ = 0,
        SB_VERT = 1,
        SB_CTL = 2,
        SB_BOTH = 3
    }

    public MyUserControl()
    {
        InitializeComponent();
        ShowScrollBar(this.Handle, (int) ScrollBarDirection.SB_VERT, true);
    }
}
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