I'm a beginner in vb.net programming and I'm slightly confused with creating controls. It seems that when I'm online the following code I see is used interchangeably:
Dim x As Button
Dim y As New Button()
or even
Dim z As New System.Windows.Forms.Button()
Does it matter how I declare the variable? Thanks in advance.
System.windows.forms.Button is the same as declaring Button. You just already have the System.windows.forms namespace imported. This is unless you have created your own button class in a different namespace, but I doubt you have.
The brackets after the name of the class will create an array of undefined size of that class. No brackets is creating one instance of that class.
The new keyword is required when creating new instances of a control. Without it, the variable you created will need to be assigned to an existing object of the same type. Seeing as you are wanting to create buttons programmatically, you should use the new keyword.
Have a look at these tutorials for a basic introduction to creating classes http://www.homeandlearn.co.uk/net/nets11p2.html http://visualbasic.about.com/od/quicktips/qt/shared_member.htm
This declares a variable of type Button called x. You cant use it until you assign something to it.
Dim x As Button
This instantiates a Button and assigns it to y. Gives yoiu a usable button "called" y
Dim y As New Button()
or even
This is the same as x, but uses a fully qualified name, for instance to to distinguish it from Jacob.Perkins.Button, if you had invented your own.
Dim z As New System.Windows.Forms.Button()
So yes it does matter.
When to use new, wehn you need to create (instantiate) one.
In .net
Dim x as Button
// followed by
x = new Button()
// is the same as
Dim x as new Button()
Dim x as button declares a variable called x that is expected to 'point to' an instance of Button.
if you said x = 36, you'd get a compiler error, because 36 isn't button it's a number. if you said x = Button1 and Button1 existed on say your form then that would be okay, given of course it was also a button.
At a certain point the only real way to "understand" this stuff it to start trying it.. Nothing horrible will happen, keep it simple and any mistakes you make will become obvious when you read the error message.
