asked on

restrict keychars on textbox

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 ?

Meir Rivkin

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

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Philippe Renaud

ASKER

what is d ?

Philippe Renaud

ASKER

nevermind ..

ASKER CERTIFIED SOLUTION

Meir Rivkin

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Philippe Renaud

ASKER

if I add Cchar(Backspace) i would put it where?

Meir Rivkin

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.

Philippe Renaud

ASKER

thanks, let me think about that combox Box yes.
thanks

kaufmed

I'd suggest deriving from the existing TextBox so that you have a resusable component.

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

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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.