numbers only textbox

  • Thread starter Thread starter Greg Burns
  • Start date Start date
G

Greg Burns

I have a textbox that I only want to allow "numbers".

1,000
1000
1000.0512

I don't want to prevent them from typing anything else, because I want to
check their input in the Validating event and will display an error with an
ErrorProvider.

First attempt (from my TextBox1 Validating event):

If TextBox1.Text = String.Empty Then
ErrorProvider1.SetError(TextBox1, "Required")
ElseIf Not IsNumeric(TextBox1.Text) Then
ErrorProvider1.SetError(TextBox1, "Not valid")
Else
ErrorProvider1.SetError(TextBox1, "")
End If

The problem with this is that "$1.00" passes the IsNumeric test. IsNumeric
considers currency a number, while I don't. :)


Second attempt:

If TextBox1.Text = String.Empty Then
ErrorProvider1.SetError(TextBox1, "Required")
ElseIf Not IsNumeric(TextBox1.Text) Then
ErrorProvider1.SetError(TextBox1, "Not valid")
Else
Try
Decimal.Parse(txtVacRemaining.Text)
ErrorProvider1.SetError(TextBox1, "")
Catch
ErrorProvider1.SetError(TextBox1, "Not valid")
End Try
End If

This works, but feels like a hack. Anybody have a better solution?

TIA,
Greg
 
Hi,

Regular expression to validate positive numbers.

Dim rNumber As New
System.Text.RegularExpressions.Regex("(^\d*\.?\d*[1-9]+\d*$)|(^[1-9]+\d*\.\d*$)")
Dim strValid() As String = {"$123.44", "1234.22", "232..232",
"2324.332", "&H244"}

For x As Integer = 0 To strValid.GetUpperBound(0)
Trace.WriteLine(String.Format("{0} matches {1}",
strValid(x), _
rNumber.IsMatch(strValid(x))))
Next

Ken
-------------------
 
OR

Private Sub NumbValidation_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles txtBox1.KeyPress, txtBox2.KeyPress
If (Not Char.IsDigit(e.KeyChar) And Not Char.IsControl(e.KeyChar)) Or Char.IsPunctuation(e.KeyChar) Then
If e.KeyChar = Char.Parse("-") Or e.KeyChar = Char.Parse(".") Then
e.Handled = False
Else
e.Handled = True
End If
End If
End Sub
 
Yeah, but I don't want to suppress keypresses. I want to display an error
after they type invalid data. (I can't stand textboxes that do that, but
that's just me).

Greg

BrianDH said:
OR

Private Sub NumbValidation_KeyPress(ByVal sender As Object, ByVal e As
Click to expand...
System.Windows.Forms.KeyPressEventArgs) Handles txtBox1.KeyPress,
txtBox2.KeyPress
If (Not Char.IsDigit(e.KeyChar) And Not Char.IsControl(e.KeyChar)) Or
Click to expand...
Char.IsPunctuation(e.KeyChar) Then
 
Doesn't work with 1,000. But I can live with that! In fact, this is
probably best.

Thanks Ken.


Ken Tucker said:
Hi,

Regular expression to validate positive numbers.

Dim rNumber As New
System.Text.RegularExpressions.Regex("(^\d*\.?\d*[1-9]+\d*$)|(^[1-9]+\d*\.\d
*$)")
Dim strValid() As String = {"$123.44", "1234.22", "232..232",
"2324.332", "&H244"}

For x As Integer = 0 To strValid.GetUpperBound(0)
Trace.WriteLine(String.Format("{0} matches {1}",
strValid(x), _
rNumber.IsMatch(strValid(x))))
Next

Ken
-------------------

Greg Burns said:
I have a textbox that I only want to allow "numbers".

1,000
1000
1000.0512

I don't want to prevent them from typing anything else, because I want to

check their input in the Validating event and will display an error with
an
ErrorProvider.

First attempt (from my TextBox1 Validating event):

If TextBox1.Text = String.Empty Then
ErrorProvider1.SetError(TextBox1, "Required")
ElseIf Not IsNumeric(TextBox1.Text) Then
ErrorProvider1.SetError(TextBox1, "Not valid")
Else
ErrorProvider1.SetError(TextBox1, "")
End If

The problem with this is that "$1.00" passes the IsNumeric test. IsNumeric

considers currency a number, while I don't. :)


Second attempt:

If TextBox1.Text = String.Empty Then
ErrorProvider1.SetError(TextBox1, "Required")
ElseIf Not IsNumeric(TextBox1.Text) Then
ErrorProvider1.SetError(TextBox1, "Not valid")
Else
Try
Decimal.Parse(txtVacRemaining.Text)
ErrorProvider1.SetError(TextBox1, "")
Catch
ErrorProvider1.SetError(TextBox1, "Not valid")
End Try
End If

This works, but feels like a hack. Anybody have a better solution?

TIA,
Greg
Click to expand...
Click to expand...
 
* "Greg Burns said:
1,000
1000
1000.0512

I don't want to prevent them from typing anything else, because I want to
check their input in the Validating event and will display an error with an
ErrorProvider.

First attempt (from my TextBox1 Validating event):

If TextBox1.Text = String.Empty Then
ErrorProvider1.SetError(TextBox1, "Required")
ElseIf Not IsNumeric(TextBox1.Text) Then
ErrorProvider1.SetError(TextBox1, "Not valid")
Else
ErrorProvider1.SetError(TextBox1, "")
End If

The problem with this is that "$1.00" passes the IsNumeric test. IsNumeric
considers currency a number, while I don't. :)
Click to expand...

Have a look at 'Double.TryParse'.
 
Hi Greg,

Just an idea, but have you tried just searching the string to see if
certain special characters have been entered? Built-in functions
like IndexOf and inStr are good for that. I'm not sure what the
purpose of your code is, so those functions might not be efficient,
but again, just food for thought.

Amaryllis
 
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