Radio button on the ContextMenu or ContextMenuStrip [winforms]

Question

I am searching for the way to implement a context menu item with radio button appearance like this: Windows 7's ContextMenu with RadioButton menu item

I have search through Google and SO, this post Adding RadioButtons to ContextMenu is close, but it's related to Java, and I am looking for a control or renderer in .NET for winforms.

Any solution or suggestion would be great help. Thank you.

Answer 1

Option buttons, also known as radio buttons, are similar to check boxes except that users can select only one at a time. Although by default the ToolStripMenuItem class does not provide option-button behavior, the class does provide check-box behavior that you can customize to implement option-button behavior for menu items in a MenuStrip control.

When the CheckOnClick property of a menu item is true, users can click the item to toggle the display of a check mark. The Checked property indicates the current state of the item. To implement basic option-button behavior, you must ensure that when an item is selected, you set the Checked property for the previously selected item to false.

The following procedures describe how to implement this and additional functionality in a class that inherits the ToolStripMenuItem class. The ToolStripRadioButtonMenuItem class overrides members such as OnCheckedChanged and OnPaint to provide the selection behavior and appearance of option buttons. Additionally, this class overrides the Enabled property so that options on a submenu are disabled unless the parent item is selected.

First Create a Class for RadioButton

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This is combination of RadioButton and ToggleButton.

Public Class ToolStripRadioButtonMenuItem
Inherits ToolStripMenuItem

Public Sub New()
    MyBase.New()
    Initialize()
End Sub

Public Sub New(ByVal text As String)
    MyBase.New(text, Nothing, CType(Nothing, EventHandler))
    Initialize()
End Sub

Public Sub New(ByVal image As Image)
    MyBase.New(Nothing, image, CType(Nothing, EventHandler))
    Initialize()
End Sub

Public Sub New(ByVal text As String, ByVal image As Image)
    MyBase.New(text, image, CType(Nothing, EventHandler))
    Initialize()
End Sub

Public Sub New(ByVal text As String, _
    ByVal image As Image, ByVal onClick As EventHandler)
    MyBase.New(text, image, onClick)
    Initialize()
End Sub

Public Sub New(ByVal text As String, ByVal image As Image, _
    ByVal onClick As EventHandler, ByVal name As String)
    MyBase.New(text, image, onClick, name)
    Initialize()
End Sub

Public Sub New(ByVal text As String, ByVal image As Image, _
    ByVal ParamArray dropDownItems() As ToolStripItem)
    MyBase.New(text, image, dropDownItems)
    Initialize()
End Sub

Public Sub New(ByVal text As String, ByVal image As Image, _
    ByVal onClick As EventHandler, ByVal shortcutKeys As Keys)
    MyBase.New(text, image, onClick)
    Initialize()
    Me.ShortcutKeys = shortcutKeys
End Sub

' Called by all constructors to initialize CheckOnClick.
Private Sub Initialize()
    CheckOnClick = True
End Sub

Protected Overrides Sub OnCheckedChanged(ByVal e As EventArgs)

    MyBase.OnCheckedChanged(e)

    ' If this item is no longer in the checked state, do nothing.
    If Not Checked Then Return

    ' Clear the checked state for all siblings. 
    For Each item As ToolStripItem In Parent.Items

        Dim radioItem As ToolStripRadioButtonMenuItem = _
            TryCast(item, ToolStripRadioButtonMenuItem)
        If radioItem IsNot Nothing AndAlso _
            radioItem IsNot Me AndAlso _
            radioItem.Checked Then

            radioItem.Checked = False

            ' Only one item can be selected at a time, 
            ' so there is no need to continue.
            Return

        End If
    Next

End Sub

Protected Overrides Sub OnClick(ByVal e As EventArgs)

    ' If the item is already in the checked state, do not call 
    ' the base method, which would toggle the value. 
    If Checked Then Return

    MyBase.OnClick(e)
End Sub

' Let the item paint itself, and then paint the RadioButton
' where the check mark is displayed, covering the check mark
' if it is present.
Protected Overrides Sub OnPaint(ByVal e As PaintEventArgs)

    MyBase.OnPaint(e)

    ' If the client sets the Image property, the selection behavior
    ' remains unchanged, but the RadioButton is not displayed and the
    ' selection is indicated only by the selection rectangle. 
    If Image IsNot Nothing Then Return

    ' Determine the correct state of the RadioButton.
    Dim buttonState As RadioButtonState = RadioButtonState.UncheckedNormal
    If Enabled Then
        If mouseDownState Then
            If Checked Then
                buttonState = RadioButtonState.CheckedPressed
            Else
                buttonState = RadioButtonState.UncheckedPressed
            End If
        ElseIf mouseHoverState Then
            If Checked Then
                buttonState = RadioButtonState.CheckedHot
            Else
                buttonState = RadioButtonState.UncheckedHot
            End If
        Else
            If Checked Then buttonState = RadioButtonState.CheckedNormal
        End If
    Else
        If Checked Then
            buttonState = RadioButtonState.CheckedDisabled
        Else
            buttonState = RadioButtonState.UncheckedDisabled
        End If
    End If

    ' Calculate the position at which to display the RadioButton.
    Dim offset As Int32 = CInt((ContentRectangle.Height - _
        RadioButtonRenderer.GetGlyphSize( _
        e.Graphics, buttonState).Height) / 2)
    Dim imageLocation As Point = New Point( _
        ContentRectangle.Location.X + 4, _
        ContentRectangle.Location.Y + offset)

    ' If the item is selected and the RadioButton paints with partial
    ' transparency, such as when theming is enabled, the check mark
    ' shows through the RadioButton image. In this case, paint a 
    ' non-transparent background first to cover the check mark.
    If Checked AndAlso RadioButtonRenderer _
        .IsBackgroundPartiallyTransparent(buttonState) Then

        Dim glyphSize As Size = RadioButtonRenderer _
            .GetGlyphSize(e.Graphics, buttonState)
        glyphSize.Height -= 1
        glyphSize.Width -= 1
        Dim backgroundRectangle As _
            New Rectangle(imageLocation, glyphSize)
        e.Graphics.FillEllipse( _
            SystemBrushes.Control, backgroundRectangle)
    End If

    RadioButtonRenderer.DrawRadioButton( _
        e.Graphics, imageLocation, buttonState)

End Sub

Private mouseHoverState As Boolean = False

Protected Overrides Sub OnMouseEnter(ByVal e As EventArgs)
    mouseHoverState = True

    ' Force the item to repaint with the new RadioButton state.
    Invalidate()

    MyBase.OnMouseEnter(e)
End Sub

Protected Overrides Sub OnMouseLeave(ByVal e As EventArgs)
    mouseHoverState = False
    MyBase.OnMouseLeave(e)
End Sub

Private mouseDownState As Boolean = False

Protected Overrides Sub OnMouseDown(ByVal e As MouseEventArgs)
    mouseDownState = True

    ' Force the item to repaint with the new RadioButton state.
    Invalidate()

    MyBase.OnMouseDown(e)
End Sub

Protected Overrides Sub OnMouseUp(ByVal e As MouseEventArgs)
    mouseDownState = False
    MyBase.OnMouseUp(e)
End Sub

' Enable the item only if its parent item is in the checked state 
' and its Enabled property has not been explicitly set to false. 
Public Overrides Property Enabled() As Boolean
    Get
        Dim ownerMenuItem As ToolStripMenuItem = _
            TryCast(OwnerItem, ToolStripMenuItem)

        ' Use the base value in design mode to prevent the designer
        ' from setting the base value to the calculated value.
        If Not DesignMode AndAlso _
            ownerMenuItem IsNot Nothing AndAlso _
            ownerMenuItem.CheckOnClick Then
            Return MyBase.Enabled AndAlso ownerMenuItem.Checked
        Else
            Return MyBase.Enabled
        End If
    End Get

    Set(ByVal value As Boolean)
        MyBase.Enabled = value
    End Set
End Property

' When OwnerItem becomes available, if it is a ToolStripMenuItem 
' with a CheckOnClick property value of true, subscribe to its 
' CheckedChanged event. 
Protected Overrides Sub OnOwnerChanged(ByVal e As EventArgs)

    Dim ownerMenuItem As ToolStripMenuItem = _
        TryCast(OwnerItem, ToolStripMenuItem)

    If ownerMenuItem IsNot Nothing AndAlso _
        ownerMenuItem.CheckOnClick Then
        AddHandler ownerMenuItem.CheckedChanged, New  _
            EventHandler(AddressOf OwnerMenuItem_CheckedChanged)
    End If

    MyBase.OnOwnerChanged(e)

End Sub

' When the checked state of the parent item changes, 
' repaint the item so that the new Enabled state is displayed. 
Private Sub OwnerMenuItem_CheckedChanged( _
    ByVal sender As Object, ByVal e As EventArgs)
    Invalidate()
End Sub

End Class

Second Create a Class of Form1

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Public Class Form1

Inherits Form

Private sample As New MenuStrip()
Private mainToolStripMenuItem As New ToolStripMenuItem()
Private toolStripMenuItem1 As New ToolStripMenuItem()
Private toolStripRadioButtonMenuItem1 As New ToolStripRadioButtonMenuItem()
Private toolStripRadioButtonMenuItem2 As New ToolStripRadioButtonMenuItem()
Private toolStripRadioButtonMenuItem3 As New ToolStripRadioButtonMenuItem()
Private toolStripRadioButtonMenuItem4 As New ToolStripRadioButtonMenuItem()
Private toolStripRadioButtonMenuItem5 As New ToolStripRadioButtonMenuItem()
Private toolStripRadioButtonMenuItem6 As New ToolStripRadioButtonMenuItem()

Public Sub New()

    Me.mainToolStripMenuItem.Text = "main"
    toolStripRadioButtonMenuItem1.Text = "option 1"
    toolStripRadioButtonMenuItem2.Text = "option 2"
    toolStripRadioButtonMenuItem3.Text = "option 2-1"
    toolStripRadioButtonMenuItem4.Text = "option 2-2"
    toolStripRadioButtonMenuItem5.Text = "option 3-1"
    toolStripRadioButtonMenuItem6.Text = "option 3-2"
    toolStripMenuItem1.Text = "toggle"
    toolStripMenuItem1.CheckOnClick = True

    mainToolStripMenuItem.DropDownItems.AddRange(New ToolStripItem() { _
        toolStripRadioButtonMenuItem1, toolStripRadioButtonMenuItem2, _
        toolStripMenuItem1})
    toolStripRadioButtonMenuItem2.DropDownItems.AddRange( _
        New ToolStripItem() {toolStripRadioButtonMenuItem3, _
        toolStripRadioButtonMenuItem4})
    toolStripMenuItem1.DropDownItems.AddRange(New ToolStripItem() { _
        toolStripRadioButtonMenuItem5, toolStripRadioButtonMenuItem6})

    sample.Items.AddRange(New ToolStripItem() {mainToolStripMenuItem})
    Controls.Add(sample)
    MainMenuStrip = sample
    Text = "ToolStripRadioButtonMenuItem demo"
End Sub
End Class

Last is Create a Class for Program

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Public Class Program

<STAThread()> Public Shared Sub Main()
    Application.EnableVisualStyles()
    Application.SetCompatibleTextRenderingDefault(False)
    Application.Run(New Form1())
End Sub

End Class

Screenshot

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Credits to Karl Erickson and to his blog about RadioButton and Menustrip.

Check his blog here.