How to validate textbox accept only negative float numbers in .net

[krishnaneeraja]

Hi,

Iam developing windows application using vb.net with c#.net.In this i want to validate textbox accept only negative float numbers like -2.3 etc....
please help me.

[r035198x]

What have you tried so far?

[madankarmukta]

HI,
You can use regular expression for this.. This is very effective to validate the any input from the user.

Thanks!

[cloud255]

A try catch statement trying to parse the input to a float will allow you to check if the number is a float. Then just multiply by -1 and see if the result is less than 0.

[jodi]

is this a windows app?

if it is, then you need to do something like this in the OnTextChanged event:

decimal dec;

decimal.TryParse(this.Text, out dec);

if (dec < 0)
Ok
else
whatever

if you want to put a mask on your textbox, you can try several there are in the net to be downloaded

tried google and the first seems to do what you want
http://www.csharphelp.com/archives2/archive305.html

cya

[Plater]

It would probably be overkill, but there is a MaskedTextBox class in .NET for windows applications that could be used.

[Curtis Rutland]

How do you develop an app using "vb.net with C#.net"?