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.NET windows forms interview questions
1) Write a
simple Windows Forms MessageBox statement.
System.Windows.Forms.MessageBox.Show
(\"Hello, Windows Forms\");
Can you write a class without specifying namespace? Which
namespace does it belong to by default??
Yes, you can, then the class belongs to global namespace
which has no name. For commercial products, naturally, you
wouldn’t want global namespace.
You are designing a GUI application with a windows and
several widgets on it. The user then resizes the app window
and sees a lot of grey space, while the widgets stay in
place. What’s the problem? One should use anchoring for
correct resizing. Otherwise the default property of a widget
on a form is top-left, so it stays at the same location when
resized.
How can you save the desired properties of Windows Forms
application? .config files in .NET are supported through the
API to allow storing and retrieving information. They are
nothing more than simple XML files, sort of like what .ini
files were before for Win32 apps.
So how do you retrieve the customized properties of a .NET
application from XML .config file? Initialize an instance of
AppSettingsReader class. Call the GetValue method of
AppSettingsReader class, passing in the name of the property
and the type expected. Assign the result to the appropriate
variable.
Can you automate this process? In Visual Studio yes, use
Dynamic Properties for automatic .config creation, storage
and retrieval.
My progress bar freezes up and dialog window shows blank,
when an intensive background process takes over. Yes, you
should’ve multi-threaded your GUI, with taskbar and main
form being one thread, and the background process being the
other.
What’s the safest way to deploy a Windows Forms app? Web
deployment: the user always downloads the latest version of
the code, the program runs within security sandbox, properly
written app will not require additional security privileges.
Why is it not a good idea to insert code into
InitializeComponent method when working with Visual Studio?
The designer will likely through it away, most of the code
inside InitializeComponent is auto-generated.
What’s the difference between WindowsDefaultLocation and
WindowsDefaultBounds? WindowsDefaultLocation tells the form
to start up at a location selected by OS, but with
internally specified size. WindowsDefaultBounds delegates
both size and starting position choices to the OS.
What’s the difference between Move and LocationChanged?
Resize and SizeChanged? Both methods do the same, Move and
Resize are the names adopted from VB to ease migration to
C#.
How would you create a non-rectangular window, let’s say an
ellipse? Create a rectangular form, set the TransparencyKey
property to the same value as BackColor, which will
effectively make the background of the form transparent.
Then set the FormBorderStyle to FormBorderStyle.None, which
will remove the contour and contents of the form.
How do you create a separator in the Menu Designer? A hyphen
‘-’ would do it. Also, an ampersand ‘&’ would underline the
next letter.
How’s anchoring different from docking? Anchoring treats the
component as having the absolute size and adjusts its
location relative to the parent form. Docking treats the
component location as absolute and disregards the component
size. So if a status bar must always be at the bottom no
matter what, use docking. If a button should be on the top
right, but change its position with the form being resized,
use anchoring. |
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