Develop Reference

How to make a listbox appear on the form at the click of a button?

I'm a university student therefore I'm not sure on everything to do with writing code. If you could provide hints or a bit of help. I have hidden the listbox via the designer. I've tried listbox1.Show under next button event handler. I've tried looking around on the web but I'm getting no where.
Now answered. Thank you

The solution depends on how you've hidden your listbox. If you did set visible property to false, just use listbox1.Visible = true;.
If you used ' Send to back' to hide it behind another control, you can use listbox1.BringToFront(); to set it into the foreground.
See https://msdn.microsoft.com/en-gb/library/system.windows.forms.control.visible.aspx and https://msdn.microsoft.com/en-gb/library/system.windows.forms.control.bringtofront.aspx

Inside Button_Click Event write:
listbox1.Visible = true;

In my opinion, the best way to show/hide controls (in WPF) is to collapse them. This allows the rest of the controls to behave as if the collapsed control does not even exists, until it is made visible, of course.
This would be done like so:
control1.Visibility = Visibility.Collapsed;
control1.Visibility = Visibility.Visible;
If you are using WinForms, controls will not have a collapse option, and the correct way would be as Almansour has said.

How to change the background image of a button when clicked in code?

There is a similar question like mine here in Stackoverflow but it only explains how to change it in XAML. I want to know how can I change it in code.
Here is a image that shows how I do it in XAML using Blend:
Link for full size: https://snag.gy/4Skk4.jpg
Basically I want to change the background of a button's pressed state in C# but I can't seem to find any examples on the Internet. It must be in code because sometimes the image of the button will change therefore the button's pressed image must change as well.
The following code is just to change the image of the button and it's just the start.
image.ImageSource = new System.Windows.Media.Imaging.BitmapImage(new Uri(#"images/Button-warning-icon.png", UriKind.Relative));
image.Stretch = Stretch.Uniform;
buttonWarnings.Background = image;

If I understand you correctly, you are trying to change the appearance of the Button control in a "pressed" visual state.
I'm not near my dev computer to try it out, but to "unblock you" I'll give a direction.
First, as you noticed in your Blend screenshot, each visual state is represented with a Storyboard, which defines how various properties change. In your case, you're looking to change Background property.
The VisualStateGroups and their states are defined by the control. You can override them when you re-template the control. So, retemplate the button control using Blend with "Edit Template"->"Edit Copy".
Then, in code, you should be able to do the following:
1) Get visual states (this would not work unless you re-template the control, AFAIK)
var visualStateGroups = VisualStateManager.GetVisualStateGroups(buttonWarnings);
2) Get the VisualStateGroup of "CommonStates" from the visualStateGroups
collection
var commonStatesGroup = visualStateGroups.Find((g) => ((VisualStateGroup)g).Name == "CommonStates") as VisualStateGroup;
3) Get the "Pressed" VisualState:
var pressedVisualState = commonStatesGroup.Find((vs) => ((VisualState)vs).Name == "Pressed") as VisualState;
4) Change the storyboard of that state
pressedVisualState.Storyboard = newStoryboardWithCustomImageBackgroundProperty;
(Disclaimer: I'm not near in a computer to try it now - it's all in theory)

There are many examples to be found on the internet!
Take a look at some:
http://mobile.dzone.com/articles/windows-phone-buttonimage
http://loekvandenouweland.com/index.php/2011/01/windows-phone-image-button/

Actually its quite simple,
While in button pressed state....see part 3 in the image you uploaded above.
Above all the colors there is a row containing 5 icons.
Click on 4th icon.
it will show you option to choose image as background.

How to force a focus on a control in windows forms

I am trying to focus a "search" textbox control in my windows forms application. This textbox is inside a user control, which is inside a panel which is inside a windows form (if it is important).
I tried 3 methods which I could find:
// 1
this.ActiveControl = myTextBox;
// 2
myTextBox.Focus();
// 3
myTextBox.Select();
Neither of them seems to work. I mean for example when I try the first one, active control is really set to myTextBox, but when I try to write something on keyboard, textbox doesn't accept it and I have to first click inside the textbox to get focus. This is same with all of the methods.
Am I missing something?

Ok, finally found the answer:
As I said my textbox is inside user control which is inside panel which is inside a form.
When I need my user control I add it to panel. To get focus on my textbox I have to firstly focus my user control so something like this:
In my top Form:
panel.Controls.Add(myUserControl);
myUserControl.Focus();
and then in my user control:
myTextBox.Select();
Note that if I used: myTextBox.Focus() it wouldn't work (don't know why). Also if I used myUserControl.Select() instead of myUserControl.Focus() it wouldn't work either.
This seems to be the only combination which works.

You could do these logic steps to set your control to be the focus:
your_control.Select();
your_control.Focus();
Enjoy! :)

Overlapping Window/Page or Custom messagebox?

I want to preface this by saying I'm a noob with WPF/.net programming.
Here is my question that requires a bit of guidance. I have a window and I load pages in and out as my navigation. On one particular page, when the user clicks on one of the items (button for example), I need to display a small form to gather more information. I'm not sure what the best approach is... what I would love (but do not know where to begin even searching for this solution) would be to open a popup balloon style window with a few textboxes and a submit button.
Other options I've explored would be to use a separate page. Save off the current page and load a new page with these textboxes and a submit button. Or to use a custom messagebox instead (least favorite option).
I would like this new extra info page to blend in with rest of the app so that the main page is still visible in the background. Any suggestions??

You can use WPF's Popup control
<Popup>
<!-- Your Content Here -->
</Popup>
Personally I have issues with WPF's Popup, so have my own custom UserControl that works like a Popup.

I ended up using modal window (ShowDialog) method for this.

How to change the background color of button in windows phone application?

I am developing window phone 7 application in C# & silverlight 4. I am new to the silverlight.I have two buttons in my application for different purposes. I want to change the color of the button dynamically when the button gets clicked. So I am using the following code
IncomeButton.Background = new SolidColorBrush(Colors.Red);
But it is not working. Can you please provide me any code or link through which I can resolve the above issue ? If I am doing anything wrong then please guide me.

Changing the styling of a button from it's own click event comes with a catch. Peter elaborates here.
Why can't I change the Background of my Button on a Click event? - Peter Torr's Blog

You can simply execute IncomeButton.UpdateLayout() after changing button's color.

I also ran into that "simple" problem. Instead of using Peter's "button styling change" thing, I simply placed a rectangle below the button and changed it's color with the Rectangle.Fill property in the Click event of the button. Works fine for me.