What causes colour discrepancies on borders after scrolling? - wpf

We noticed some weird behaviour in our WPF application.
We have a customised, expander like UserControl, which has a Border around it - we'll call it expander. There can be several of these expanders in a view, which means scrolling is needed. When an expander is scrolled out of view, and back again, the border sometimes changes colour. Not every time, and not consistantly. For example, the lower border can be slighly lighter in colour, while the right border can be darker, even though they use the same brush. The next time it's scrolled out of view, and back again, the colours can be back to normal.
It almost looks like a scaling/antialiasing effect. Has anyone else seen this behaviour, and is there anything we can do about it?
To complicate things a bit - but only a bit - the expanders are children of a ListView. This is because we want to emulate HTML anchoring, so we externally can jump directly to a given expander. Could this be part of the problem?

This seems to be a anti-aliasing issue, as explained here and here.

Related

XAML: How to set controls properties depending on screen resolution?

I'm developing WPF application (.NET 4) where I have few UserControl's which looks pretty good on most of the screens.
But now customer have new monitors where some elements are too small. The best solution we found is to make some elements smaller, to left more space for the main panel.
The layout is now pretty complex, and I spend a lot of time to find which margins, heights, widths and so on.. I need to change to implement this.
Usually it is some children elements Height, Width +-10 or so. Sometimes Margin. And in one case it's Style's Setter Property="Width" which defined in Resources.
I'm wondering is it possible to make this changes configurable, so for my specified screen resolution (let's say I know only that Width=X and Height=Y) they was applied, and for all other screens it stays the same as now?
How to do this using as less code-behind as possible?
I like the solution with VisualStateManager and VisualState.SateTriggers, but looks like my application does not recognize this.
When you are using user controls inside the window may be you could set the height and width of the grid's row and column definition to '*' and also make scroll bar visibility of horizontal and vertical scroll bar to auto.
Hope it helps you.

Changing the anchor point of the scrollviewer (WPF)

I am trying to do something a little bit specific, and I can't seem to find if it is even possible. So I thought I would lay down the question here.
What I'm looking for is a way to change the anchor point of the scrollviewer from the top to the bottom (however you look at it). I'll explain what I mean.
By default when the control contained in your scrollviewer gets taller, so will your vertical scrollbar scollableheight.
But what happens is, the vertical scrollbar will stay at the same scrolloffset from the top, while what I want is that the vertical scrollbar keeps it's position relative to the bottom. The reason I want this behaviour is because I am creating a list that the user can expand more of by scrolling to the top. but then when I add the new items it looks like the scrollviewer scrolls up to the newly added items. (although it is actually the content the is pushed down) So if the scrollviewer would have the vertical scrollbar anchored to the bottom, the visible part of the content would stays at the same position to the user because the distance from that part to the bottom didn't change.
I hope you can understand what I'm trying to do.
I allready found one way of doing this, but it is not the desired option to me.
Option 1) Apply a Scaletransform of -1 in the Y-axis to the scrollviewer to flip it upside down. Then apply another ScaleTransform of -1 in the Y-axis to the content of the scrollviewer to make the content right side up.
But the problem with this technique is that for one, when you scroll using your mousewheel the scrollviewer scrolls inverted as normal. And second, I'm using 2 scaletransformations just to change the behaviour of the scrollviewer, and not even for eye candy. So that seems a bit excessive to me.
Option 2) anyone?

How to scroll contents WHILE scrolling

I have created a usercontrol that is essentially a text editor (using Graphics.Drawstring in OnPaint).
I have set AutoScroll = true, and AutoScrollMinSize values appropriately. Everything is working how it should...
EXCEPT, i would like the control to scroll itself WHILST I am currently scrolling (i.e. click and drag the scroll bar... and whilst it is being dragged the control should be scrolling the entire time). At the moment it only scrolls when the scroll bar is released (mouse up).
I have tried implementing _Scroll and invalidating the control, but that just makes it flicker uncontrollably.
I cannot find any examples online for this, due to it being difficult to describe!
Can anyone point me in the right direction please?
Control.Invalidate() will make something flicker badly. I faced this problem drawing cross-hairs over a mouse position on a PictureBox drawing a line chart before. The trick is to use (and I cant remember which one is best to come first)
Control.Update();
Control.Refresh();
in the Scroll event. Depending on what else you are drawing in the Control and how you are drawing it this may be better for you. Also this is tested on PictureBox, Control may be another matter.

Remove all extra space around a button with an image?

Alright, try as I might, I cannot for the life of me get rid of this tiny little border around my buttons.
Edit: I should mention, in case I didn't make it clear, these are buttons with an image on them, set to flat with the button sized to the image.
Images below:
Number one, I can't for the life of me get these borders to GO AWAY. I've checked everything I can think of. They're:
flat
border 0
no margins
no padding
manually sized to the size of the image (75px)
in a table layout where the columns are all:
manually sized to the width of the image (75px)
borderless
Nothing seems to really "work" to get rid of these. If I size the columns down to be 74px instead of 75px, most of them go away, but a few remain. I've triple and quadruple checked the images, and they don't have anything that I can pick up on that should be causing this... no transparency around the borders, definitely no border that looks like that.
Which leads me to the second problem:
Settings button when dialog is small...
Settings button when dialog is stretched out.
Settings button is also in the same table layout panel.
I've checked all the settings on the table layout panel as well.. I can't find any padding or margin or anything settings that suggest this should be happening.
Does anyone have any experience with this? What am I missing..?
Simple solution: using directly a PictureBox as if it was a button. You can change your image on mouse over or mouse click.
Have you tried a Toolbar/strip/whatever it's called these days? Probably not going to help as I believe it pads on your behalf, but worth a shot.
In the end you can toss the buttons in the trash and write your own control. A single control that manages N buttons will work well here.
I don't understand your second problem. What's the problem? It'll be fixed if you roll your own control anyhow.
While not a fix for the spacing issue, as a workaround you can make that gray gradient currently "behind" the "tabs" and control panel image into a BackgroundImage for the TableLayoutPanel using BackgroundImageLayout of Stretch. While not fixing the spacing issue, it would make it unnoticeable.
Writing a winforms control has its challenges (experience speaking here). I would agree that that is whats needed however. Depending on your project you may consider using XAML and WPF. It provides that fine detail you seem to be looking for in you application.
There are ways to host XAML controls in a winform app, but if you went this route it would be best to create a native WPF application. The reverse is also true (winform controls in a WPF app).
Did you check if the image has transparent pixels around the graphic pixels you want?
May be a simple crop solution.

WPF: Changing the look of a Surface Listbox "click-effect"

I'm changing the look of some Controls that I use in my Microsoft Surface Application at the moment. And today I'm working on a SurfaceListBox.
I have the template for it and already changed background and borders and other stuff.
But I really cannot find where I can change the color of the rectangle that appears on the ListBoxItem when you touch the ListBox. At the moment it's just white and I want to change that.
It's not something like the effect that you can see when the item is selected. I already found that and changed that so my selected item now appears in a different color. But the effect in the second when you touch the item stays white.
So where can I change this effect?
If you mean the bright, white highlight that happens when you press your finger against an item you should look into the SurfaceShadowChrome. It's used by (almost) all surface controls to give feedback when the user is pressing on a control.
It does have a Color property that you can modify to suit your needs. Apart from the color, and the tweaking of corner radius and shadow offset, it's not a very flexible decorator. But hopefully, you'll be able to make it do what you need.

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