VB Help with Void Null

[redfoxstorm]

I've wrote a small VB program that except input through a textbox. After I wrote the program I want to know what is the code that will allow me to print out an error message when nothing is entered?

How can do it with a if statment? Like

if textbox1.text = null then

"label1.text = " No Input"

End If


Thats all i want to do....can anybody help?

RedFox

[VHockey86]

isnt there an "isEmpty" method (function) or something?
Haven't used VB in awhile, but i dont see why this wouldnt work

if textBox1.text() = "' then
whatever
end if

Those are two quotation marks with no space inbetween them.

[redfoxstorm]

didn't work

[redfoxstorm]

I keep getting a "cast from string "" to Integer is not valid"

whats that mean?

[large_nostril]

Try:

If textbox1.Text = "" Then
label1.Text = "No Input"
End If

If that doesn't work, check your data types (in all your statements) because something is wrong there. That's what's causing the type cast error.

[VHockey86]

... is your textbox somehow like a "number box" ?
I agree, that is very weird. I would think that everything is treated as a string from a text box.
Perhaps what you need to do is stop the current function if that error occurs.

It's probably trying to use that data later on in your program execution since setting a label to "no input" never actually stops the rest of it from executing.

You probably want to do something like

If Not textbox1.Text = "" Then
//call a function to continue execution
Else
label1.Text = "No Input", (might also want to consider using a message box here, not so discrete)
End If

Another way around it would be to set

textbox1.Text = 0 if there is no input (so, in the else statement above).

[Whir]

In the button code, put this:

If txtbox1.Text = "" Then MsgBox "No Input"

Second, just setting a label.Text to a variable will not update the forum until you do a frmWhatever.Refresh (I think is the method - it's been a while).

Third, since this isn't a multiple line statement If, you don't need to get fancy with an End If. Just tack a MsgBox behind the Then and call it a day.

BTW, the MsgBox makes a pop up box. If you WANT the form to be updated (not how you would normally want the program to work), then you should do the lblLabel.Text = "No Input" and frmForm.Refresh inside a normal If, Then, End If.

Make sense?

[Whir]

Quote:

Originally Posted by VHockey86

isnt there an "isEmpty" method (function) or something?

isEmpty works if the variable is either set to empty, or the variable is uninitialized. Even if there's no input to the box, I believe it will still be "" rather than empty.

[Blazer06]

The code that you would need to have is:

Private Sub subCheck()
If text1.text = “” then
	‘If there is no input
	Lable1.caption = “No Input”
Else
	‘If there is input
	Lable1.caption = “Input”
End if
End Sub

Then just call subCheck when you needed to check.


-Blaze

[vass0922]

have you tried
If CStr(txtBox.Text) = "" Then

OR Worst case scenario

Dim vSomeVar As Variant
vSomeVar = txtBox.Text
If vSomeVar = "" Then

or even worster scenario (this shouldn't even work seeing as a text box can't handle a NULL value
If IsNull(txtBox.Text) Then