IsNumeric [RESOLVED]

[twisted]

There is a way to verify that the contents of the text box are indeed numbers before putting them into variables. I know it's a function called IsNumeric. Can anyone post a code example on how to use it??

[Negative0]

Dim x As Double
        If IsNumeric(TextBox1.Text) Then
            x = TextBox1.Text
            MsgBox(x)
        End If

[Memnoch1207]

Imports Microsoft.VisualBasic.Information
 
Dim num1 As Integer = 10
 
If IsNumeric(num1) Then
   'It is numeric
Else
   'It is not numeric
End If

[twisted]

Thanks!

[Pirate]

This is the .NET WAY :

Try
            Dim int As Integer = Integer.Parse(Me.TextBox1.Text)
        Catch x As Exception
            MessageBox.Show("Please input numeric value")
        End Try

[MrGTI]

Have you ever tried using a NumericUpDown? They can't type letters into it, thus saving you the problem.

[TLord]

I don't recommend using Pirate's way.
Try...Catch...End Try statement is used for watching a specific are of code for throwing an exception, in other words for identifying exceptions and responding to them, not for such small type situations. I recommend using the VB.Net's built is IsNumeric function, using such function saves time and lines.
You may not find this a big problem, but what will you do if you have a program under development? where you type handreds of lines daily?
I recommend also using Try...Catch...End Try statement for covering a whole subroutine and catching specific errors and exceptions.

[Pirate]

Originally posted by TLord
I don't recommend using Pirate's way.
Try...Catch...End Try statement is used for watching a specific are of code for throwing an exception, in other words for identifying exceptions and responding to them, not for such small type situations. I recommend using the VB.Net's built is IsNumeric function, using such function saves time and lines.
You may not find this a big problem, but what will you do if you have a program under development? where you type handreds of lines daily?
I recommend also using Try...Catch...End Try statement for covering a whole subroutine and catching specific errors and exceptions.

IsNumeric is not pure .NET function . It's only for compatibilitiy issues . Everybody expect that MS will stop supporting this class (Microsoft.VisualBasic) in the future releases . As for the the Parse method it's the only pure code that does the job ! There's no problem with Try...Catch block as long as the conversion is applicable . I always use this way and it's been working great . Never fail me !

look at VIP's replies

[taxes]

Originally posted by Negative0

Dim x As Double
        If IsNumeric(TextBox1.Text) Then
            x = TextBox1.Text
            MsgBox(x)
        End If

This is a hangover from VB6. It will not work in .NET unless Option Strict is OFF. You would have to use

x=val(TextBox1.Text) or x=cdbl(TextBox1.Text)