Declaring NULL

[ICeMaN_179]

i am using

 

is null

 

in my code and i get a compile error and the debugger says that NULL needs to be declared, what does this need to be declared as ?

 

dim NULL as ???

[Bucky]

In VB.NET, to check if a class is not inialized, use Is Nothing:

 

If myObj Is Nothing Then
 ' Moo
End If

[ICeMaN_179]

would it be: (this didn't work for me)

 

if TXTInput is nothing then
msgbox "Please enter text !!", msgstyle.question, "Error"
else
exit sub
end if

[John]

Try this:

If TXTInput.Text = "" Then
   msgbox "Please enter text !!", msgboxstyle.question, "Error"
End If

Orbity

[ICeMaN_179]

yeh i know that but i would prefer to use something like,

 

Is Nothing
' or
Is Null

[Volte]

Why? Null, Nothing and "" are all different things, and so can't be

interchanged. "" is a string, while Nothing is.... nothing. It's the

lack of anything in the Text object. Stick with "". If you want to do

it a different way, you could use If txtInput.Text.Length = 0 Then. :-\

[Nerseus]

I know in C# you can use string.Empty (or String.Empty). The fastest method will always be to check the length, VolteFace's last comment.

If txtInput.Text.Length = 0 Then

 

Strings are objects in .NET and contain a header which contains, among other things, the length. It's faster to compare that a known number than to check for "" (or even string.Empty).

 

-Nerseus

[divil]

Nerseus is correct, never compare a string to "", always check the length.