how to get the type of a textbox

[Stefan Richter]

Hi,

how can I get the type of what was entered into a textbox?
I want to validate the user inputs, so I would like to know
if what the user entered was a number or not.

thanks,

Stefan

[William Ryan eMVP]

On the KeyDown event trap e.KeyChar
"Stefan Richter" <sp**@spammenot.com> wrote in message
news:c7***********@otis.netspace.net.au...

Hi,

how can I get the type of what was entered into a textbox?
I want to validate the user inputs, so I would like to know
if what the user entered was a number or not.

thanks,

Stefan

[Stefan Richter]

Okay,

so I really have to do that all by myself,
character for character??
???

Isn't there some function that automatically does it?

Thanks,

Stefan

[Scott M.]

In a web form, there are validation controls that do the job for you.

If not, you have to check the text yourself.
"Stefan Richter" <sp**@spammenot.com> wrote in message
news:c7***********@otis.netspace.net.au...

Okay,

so I really have to do that all by myself,
character for character??
???

Isn't there some function that automatically does it?

Thanks,

Stefan

[William Ryan eMVP]

It's really simple, keypress only passes one character at a time, so you can
just check the current key. If it's a number for isntance, ignore it.

like Scott mentioned, if you are using ASP.NET you can use the Regex
validators. Similarly, you can easily build this in on the desktop
controls.
"Stefan Richter" <sp**@spammenot.com> wrote in message
news:c7***********@otis.netspace.net.au...

Okay,

so I really have to do that all by myself,
character for character??
???

Isn't there some function that automatically does it?

Thanks,

Stefan

[John Scalco]

You can do this with regular expressions as mentioned in other replies to
your post.
Or you can create a function, say StringToInt("42");

Here's some code which does pretty much what StringToInt() might do

private void textBox1_TextChanged(object sender, System.EventArgs e)
{
string s = textBox1.Text;

int num = IsNumber(s);
}

private bool IsNumber (string astr)
{
try {
int i = Convert.ToInt32(astr);
return (true);
}
catch (System.Exception) {
return (false);
}
}

maybe something like that?

hth,
J

"Stefan Richter" <sp**@spammenot.com> wrote in message
news:c7***********@otis.netspace.net.au...

Okay,

so I really have to do that all by myself,
character for character??
???

Isn't there some function that automatically does it?

Thanks,

Stefan