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restrict keychars on textbox
Posted on 2013-01-07
Hi EE,
I need to restrict keyPress on a textBox. I only want the following :
Any digits before the dot, then after the dot only one of those: 25, 50 75
so for examples this is good:
4
34
12.25
9.50
66.75
this is wrong:
2.4
11.57
34.52
3.02
can you help ?
I need to restrict keyPress on a textBox. I only want the following :
Any digits before the dot, then after the dot only one of those: 25, 50 75
so for examples this is good:
4
34
12.25
9.50
66.75
this is wrong:
2.4
11.57
34.52
3.02
can you help ?
[X]
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8 Comments
here:
Private Sub textBox1_KeyDown(sender As Object, e As KeyEventArgs)
e.Handled = EvaluateText(e.KeyChar)
End Sub
Private Function EvaluateText(key As String) As Boolean
If key = "." And textBox1.Text.Contains(".") Then
Return False
End If
Dim data As String = textBox1.Text + key
Dim d As Decimal = Decimal.Parse(data)
Dim dec As Decimal = d - Math.Floor(d)
Dim arr As Decimal() = {0.25D, 0.5D, 0.75D, 0}
If arr.Contains(dec) Then
Return True
End If
Return False
End Function
i;ve made a mistake in the function, here's working:
Private Sub textBox1_KeyDown(sender As Object, e As KeyEventArgs)
e.Handled = EvaluateText(e.KeyChar)
End Sub
Private Function EvaluateText(key As String) As Boolean
If key = "." And textBox1.Text.Contains(".") Then
Return True
End If
If Not key = "." And Not TextBox1.Text.Contains(".") Then
Return False
End If
Dim data As String = textBox1.Text + key
Dim d As Decimal = Decimal.Parse(data)
Dim dec As Decimal = d - Math.Floor(d)
Dim arr As Decimal() = {0.25D, 0.5D, 0.75D, 0}
If arr.Contains(dec) Then
Return False
End If
Return True
End Function
it would be easier for you to have numeric control and combobox control with {.25,.50,.75,0} values.
cause the validation code is overkill to what you want to achieve.
using 2 controls and your validation is complete, no errors.
cause the validation code is overkill to what you want to achieve.
using 2 controls and your validation is complete, no errors.
Active today
I'd suggest deriving from the existing TextBox so that you have a resusable component.
e.g.
If you added this code to your project, then built it, you would then have a component you can drag from the ToolBox onto your form.
e.g.
Public Class QuarterlyTextbox
Inherits TextBox
Private _validKeys As New List(Of Keys) From
{
Keys.D0, Keys.NumPad0,
Keys.D1, Keys.NumPad1,
Keys.D2, Keys.NumPad2,
Keys.D3, Keys.NumPad3,
Keys.D4, Keys.NumPad4,
Keys.D5, Keys.NumPad5,
Keys.D6, Keys.NumPad6,
Keys.D7, Keys.NumPad7,
Keys.D8, Keys.NumPad8,
Keys.D9, Keys.NumPad9,
Keys.Decimal, Keys.OemPeriod
}
Private _controlKeys As New List(Of Keys) From
{
Keys.Back, Keys.Delete,
Keys.Left, Keys.Right,
Keys.Home, Keys.End
}
Protected Overrides Sub OnKeyDown(e As KeyEventArgs)
If _controlKeys.Contains(e.KeyData) Then
MyBase.OnKeyDown(e)
Return
End If
If (Not _validKeys.Contains(e.KeyData)) OrElse
(Me.Text.EndsWith(".25") OrElse Me.Text.EndsWith(".50") OrElse Me.Text.EndsWith(".75")) OrElse
(Me.Text.Contains(".") AndAlso (e.KeyData = Keys.Decimal OrElse e.KeyData = Keys.OemPeriod)) OrElse
(Me.Text.EndsWith(".") AndAlso e.KeyData <> Keys.D2 AndAlso e.KeyData <> Keys.NumPad2 _
AndAlso e.KeyData <> Keys.D5 AndAlso e.KeyData <> Keys.NumPad5 _
AndAlso e.KeyData <> Keys.D7 AndAlso e.KeyData <> Keys.NumPad7) OrElse
((Me.Text.EndsWith(".2") OrElse Me.Text.EndsWith(".7")) AndAlso e.KeyData <> Keys.D5 AndAlso e.KeyData <> Keys.NumPad5) OrElse
(Me.Text.EndsWith(".5") AndAlso e.KeyData <> Keys.D0 AndAlso e.KeyData <> Keys.NumPad0) Then
e.SuppressKeyPress = True
e.Handled = True
Return
End If
MyBase.OnKeyDown(e)
End Sub
End Class
If you added this code to your project, then built it, you would then have a component you can drag from the ToolBox onto your form.
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