Black window remains open even after closing the window programatically

Question

I have an application which has multiple windows. From mainwindow button click event I am closing the child form of the application. The child window is opened after a successful socket, serial or gateway connection attempt, after which the application
do work with some threads and while clicking on a button on mainwindow I am closing this child window after disconnecting the respective connection mode. But after the close event the child window background gets black and it remains open unless and until
I just do a minimize and maximize the application. Please help me on this to get this issue fixed.

Answer 1

Well the details are rather going to depend on what it's doing.
It's a very open ended question really.
But...
Your options include.
Background worker.
https://msdn.microsoft.com/en-us/library/cc221403(v=vs.95).aspx
DIspatcherTimer
https://msdn.microsoft.com/en-us/library/system.windows.threading.dispatchertimer(v=vs.110).aspx
Async Await
https://msdn.microsoft.com/en-us/library/hh191443.aspx
Tasks
Task.Factory.StartNew(() => { Dosomething(); });
Or just a plain thread
using System.Threading;
new Thread(() =>
Thread.CurrentThread.IsBackground = true;
// DoSomething();
}).Start();
Where DoSomething is a method.
You can also have inline code of course instead of a method.
Whilst on a different thread to the UI you can't update UI objects.
You'll get a thread affinity error message if you try.
That means you either return your results to the ui thread and process them there ( particularly convenient with async await ).
Or you update something which doesn't have thread affinity.
An observablecollection bound to an itemssource doesn't have thread affinity eg.
You do need to raise property changed at the end of your processing with that option because it notifies collectionchanged on the wrong thread and the UI won't know it changed.
Or you can dispathcher.begininvoke to get back to the UI thread.
All depends what you're doing but hopefully one of those options there will suit you.
Hope that helps.
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