How do I get a radio box that permits no selections? - vb.net

Question

I have a pair of radio buttons on top of a panel to function as a radio box, and it is mostly fine, but I need the user to have the option of leaving both of them unchecked (I wish the user to select zero or one of the options). They are both unchecked when the form is displayed, but after the user checks one of them, it is impossible to revert to the original state. I would expect clicking the selected radio box would clear it (I vaguely remember this from my X/Motif days) but that doesn't seem to happen.
How do I program the radio buttons to allow both of them the be unchecked? Or should I be using some other control for this purpose?

Answer 1

There is no built in way to do what you're asking for. It is not that hard to do it our-self. Here's the sample code which shows how to do that.
C# version:
private void Initialize()
{
radioButton1.AutoCheck = false;
radioButton2.AutoCheck = false;
radioButton1.Click += radioButton_Click;
radioButton2.Click += radioButton_Click;
}
void radioButton_Click(object sender, EventArgs e)
{
RadioButton radio = (RadioButton)sender;
radio.Checked = !radio.Checked;
if (!radio.Checked)
{
return;
}
var otherRadios = radio.Parent
.Controls
.OfType<RadioButton>()
.Where(r => r != radio);
foreach (var r in otherRadios)
{
r.Checked = !radio.Checked;
}
}
Vb.net version:(Converted using http://converter.telerik.com/)
Private Sub Initialize()
radioButton1.AutoCheck = False
radioButton2.AutoCheck = False
AddHandler radioButton1.Click, AddressOf radioButton_Click
AddHandler radioButton2.Click, AddressOf radioButton_Click
End Sub
Private Sub radioButton_Click(sender As Object, e As EventArgs)
Dim radio As RadioButton = DirectCast(sender, RadioButton)
radio.Checked = Not radio.Checked
If Not radio.Checked Then
Return
End If
Dim otherRadios = radio.Parent.Controls.OfType(Of RadioButton)().Where(Function(r) r <> radio)
For Each r As var In otherRadios
r.Checked = Not radio.Checked
Next
End Sub

Answer 2

It should be simple if you think hatke.. Create your custom control
Imports System.ComponentModel
Public Class MyRadio
Inherits RadioButton
Private _permitted As Boolean = True
<DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)> _
<Browsable(True)> _
Public Property Permitted() As Boolean
Get
Return _permitted
End Get
Set(ByVal value As Boolean)
_permitted = value
End Set
End Property
Protected Overrides Sub OnClick(ByVal e As System.EventArgs)
If _permitted Then MyBase.OnClick(e)
End Sub
End Class
HOW TO USE IT?
myRadio1.Permitted = False 'Assigning it to false will not allow you to select it.

Answer 3

You can use checkboxes, they can be checked and unchecked.
If you really want to uncheck a radio button then use the code below:
Private Sub RadioButton1_MouseDown(sender As Object, e As MouseEventArgs) Handles RadioButton1.MouseDown
If RadioButton1.Checked = True Then
Dim thr As New Threading.Thread(AddressOf unticker)
thr.Start()
End If
End Sub
Private Sub unticker()
Threading.Thread.Sleep(100)
Do Until RadioButton1.Checked = False
Invoke(Sub() RadioButton1.Checked = False)
Loop
End Sub
Use this for each radiobutton individually