在VB.net中使用自定义控件处理焦点

Question

I have a custom control I'm creating. When I click on it, it draws a dotted border and puts some nubs on it for resizing. This all works perfectly. Now I want it so when I click off of it, it deselects. I already have a variable to set up if it's selected or not and subs to draw/clear it. I just have to be able to detect when something else is selected or it gets clicked off of.

What I've Tried

My first and best solution to this was to use the LostFocus event, but, by custom control apparently won't let it fire. After some research, as far as I know, custom controls don't have Focus events because they are custom and could be changed (basically, you have to implement the focus events yourself).

My Question

Does anybody have a solution to either implement the focus events or a way to handle off clicking for custom controls?

Sources

Here is my controls current source:

Imports System.Drawing.Drawing2D

Public Class wDOMElement
    Inherits Control

    Public selected As Boolean = False

    Private mdown As Boolean = False
    Private moffset As Point = Nothing

    Private nubs As New List(Of PictureBox)

    Private Sub wDOMElement_GotFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.GotFocus
        MsgBox("test <-- DOES NOT SHOW!")
    End Sub

    Private Sub wDesignEditor_MouseDown(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseDown
        If mdown Then Return
        mdown = True
        moffset = MousePosition - Location
        selectME()
    End Sub

    Private Sub selectME()
        selected = True
        updateDraw()
        updateBorder()
        For Each v As PictureBox In nubs
            v.Show()
        Next
    End Sub

    Private Sub unselectME()
        selected = False
        updateBorder()
        updateDraw()
        For Each v As PictureBox In nubs
            v.Hide()
        Next
    End Sub

    Private Sub updateBorder()
        Using gfx As Graphics = Graphics.FromHwnd(Me.Handle)
            gfx.Clear(BackColor)
            If selected Then
                Dim blackPen As New Pen(Brushes.Black)
                blackPen.DashStyle = DashStyle.Dot
                gfx.DrawRectangle(blackPen, 4, 4, Width - 9, Height - 9)
            End If
        End Using
    End Sub

    Private Sub updateDraw()
        'Needs to be overriden
    End Sub

    Private Sub configureFirstSelection()
        Using gfx As Graphics = Graphics.FromHwnd(Me.Handle)
            Dim blackPen As New Pen(Brushes.Black)
            blackPen.DashStyle = DashStyle.Dot
            gfx.DrawRectangle(blackPen, 4, 4, Width - 9, Height - 9)
            'Top Handle
            placeHandle(My.Resources.Handle, CInt(Width / 2 - 3), CInt(0), New Point(0, 1), New Point(0, -1), Cursors.SizeNS, AnchorStyles.Top)
            'Bottom Handle
            placeHandle(My.Resources.Handle, CInt(Width / 2 - 3), CInt(Height - 7), New Point(0, 0), New Point(0, 1), Cursors.SizeNS, AnchorStyles.Bottom)
            'Left Handle
            placeHandle(My.Resources.Handle, CInt(0), CInt(Height / 2 - 3), New Point(1, 0), New Point(-1, 0), Cursors.SizeWE, AnchorStyles.Left)
            'Right Handle
            placeHandle(My.Resources.Handle, CInt(Width - 7), CInt(Height / 2 - 3), New Point(0, 0), New Point(1, 0), Cursors.SizeWE, AnchorStyles.Right)
            'Top Left Handle
            placeHandle(My.Resources.Handle, CInt(0), CInt(0), New Point(1, 1), New Point(-1, -1), Cursors.SizeNWSE, AnchorStyles.Top + AnchorStyles.Left)
            'Top Right Handle
            placeHandle(My.Resources.Handle, CInt(Width - 7), CInt(0), New Point(0, 1), New Point(1, -1), Cursors.SizeNESW, AnchorStyles.Top + AnchorStyles.Right)
            'Bottom Left Handle
            placeHandle(My.Resources.Handle, CInt(0), CInt(Height - 7), New Point(1, 0), New Point(-1, 1), Cursors.SizeNESW, AnchorStyles.Bottom + AnchorStyles.Left)
            'Bottom Right Handle
            placeHandle(My.Resources.Handle, CInt(Width - 7), CInt(Height - 7), New Point(0, 0), New Point(1, 1), Cursors.SizeNWSE, AnchorStyles.Bottom + AnchorStyles.Right)
        End Using
    End Sub

    Private Sub placeHandle(ByVal pic As Image, ByVal x As Integer, ByVal y As Integer, ByVal mov As Point, ByVal siz As Point, ByVal cur As Cursor, ByVal ancr As AnchorStyles)
        Dim nPB As New PictureBox
        nPB.SizeMode = PictureBoxSizeMode.AutoSize
        nPB.Image = pic
        nPB.Location = New Point(x, y)
        nPB.Cursor = cur
        nPB.Visible = False
        nPB.Anchor = ancr
        nPB.Parent = Me
        Dim md As Boolean = False
        Dim lpos As Point = Nothing
        Dim moveClock As New Timer
        moveClock.Interval = 1
        moveClock.Enabled = False
        AddHandler nPB.MouseDown, Sub()
                                      md = True
                                      lpos = MousePosition
                                      moveClock.Start()
                                  End Sub

        AddHandler moveClock.Tick, Sub()
                                       If md Then
                                           Dim nX As Integer = (MousePosition.X - lpos.X) * mov.X
                                           Dim nY As Integer = (MousePosition.Y - lpos.Y) * mov.Y
                                           Dim nWidth As Integer = (MousePosition.X - lpos.X) * siz.X
                                           Dim nHeight As Integer = (MousePosition.Y - lpos.Y) * siz.Y
                                           Left += nX
                                           Top += nY
                                           Width += nWidth
                                           Height += nHeight
                                           lpos = MousePosition
                                           updateDraw()
                                           updateBorder()
                                       End If
                                   End Sub
        AddHandler nPB.MouseUp, Sub()
                                    md = False
                                    moveClock.Stop()
                                End Sub
        nubs.Add(nPB)
    End Sub

    Private Sub wDesignEditor_MouseMove(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseMove
        If mdown Then
            Location = MousePosition - moffset
        End If
    End Sub

    Private Sub wDesignEditor_MouseUp(ByVal sender As Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Me.MouseUp
        mdown = False
    End Sub

End Class

Answer 1

Try using the Enter and Leave events for your custom control.

GotFocus and LostFocus have sort of been deprecated in favor of Enter and Leave.

Update:

Since you are inheriting from Control, you should probably be overriding your events, not handling them. MouseDown won't necessarily grab the focus either, so you should probably check that, too:

Example:

Public Class ControlEx
  Inherits Control

  Protected Overrides Sub OnEnter(e As EventArgs)
    MyBase.OnEnter(e)
    MessageBox.Show("Hello")
  End Sub

  Protected Overrides Sub OnLeave(e As EventArgs)
    MyBase.OnLeave(e)
    MessageBox.Show("Good-bye")
  End Sub

  Protected Overrides Sub OnMouseDown(e As MouseEventArgs)
    If Me.Enabled AndAlso Not Me.Focused Then
      Me.Focus()
    End If

    MyBase.OnMouseDown(e)
  End Sub

End Class