CODEWITHSUNDEEP
c#winforms
Neeraj Kaushik
Neeraj Kaushik

Reputation: 354

How to move scroll bar value by percentage in Winforms?

I am not sure if it is a duplicate question but I could not find any answer on StackOverflow.

Problem Statement: I have Third party Image Viewer and PDF viewer controls. which are embedded into C# WinForms page. I want to control scrollbars movement in percentage. For example, if I press "down" key then vertical scroll bar should move down to 20% of page height. I have tried with below logic:

_imageViewer.VerticalScrollBar.Value += _imageHeight X ZoomFactor X .20
OR
_imageViewer.VerticalScrollBar.Value += pdfViewer1.VerticalScroll.Maximum X .20

Both approaches are not giving me the exact result. I think I should also consider thumb size of scroll bar but I don't know how can I get that value.

Please suggest me any good approach to moving scrollbar in the percentage of image height or width.

Upvotes: 1

Views: 1905

Answers (1)

Reza Aghaei
Reza Aghaei

Reputation: 125207

You can assign SmallChange property of ScrollBar to suitable value. As mentioned in documentations, When the user presses one of the arrow keys or clicks one of the scroll bar buttons, the Value property changes according to the value set in the SmallChange property.

Example:

vScrollBar1.SmallChange = ((vScrollBar1.Maximum - vScrollBar1.Minimum) * 20 / 100);

Upvotes: 2

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