Scrolling with GDI

[Echilon]

I'm trying to draw a sort of table onto a UserControl in C#. The table will resemble something like an Excel spreadsheet, with a header at the top and a column visible to the left side (these will always be visible, regardless of scroll state). I'm also going to have a number of vertical columns, each of which will line up with a rectangle on the header. I've split my UserControl into two sectione by adding panels, one for the header and one for the rest. The problem is the scrolling.

I can't see to get the panel to scroll, even though there are rectangles drawn outisde the visible co-ordinates and autoscroll is set to true.

I read that drawing to a bitmap might be an option, but I need to process mouse clicks on elements which are drawn inside the columns. I was thinkining of splitting them each into separate UserControls, then rendering each one and the sub-controls it contains. This would allow me to process mouse events much more easily.

Would this be the best option? Is it even possible to scroll a panel when you're drawing with GDI?

 

[JurkMonkey]

If you are purely drawing using GDI+ then you have to manually set the scrollbar max value and handle the scroll event. When the scroll event occurs - you need to calculate where the scroll bar is and redraw your control as desired. For instance, if you had a 1000 cells and 100 fit in the view at any given time, you could set a max scroll of 10. then for every increase of 1 on the scrollbar you would move 100 cells.

It takes a bit of work in getting the scrolling right but it will have the best performance. If you want to do 3 separate controls that is also good but be aware that the other panels will lag a bit behind the scroll of the main control. It's just due to the drawing order of your controls and the speed of GDI+.

http://www.ubuntu.com/

 

[Echilon]

I've managed to get it working by using panelName.AutoScrollPosition.