在VB.net中使用自定義控件處理焦點

Question

我有一個正在創建的自定義控件。 當我單擊它時，它會繪制一個虛線邊框，並在其上放一些小塊以調整大小。 所有這一切都完美。 現在我想要它，所以當我單擊它時，它會取消選擇。 我已經有了一個變量來設置是否被選中，以及用來繪制/清除它的子控件。 我只需要能夠檢測何時選擇了其他選項或將其單擊。

我嘗試過的

我對此的第一個也是最好的解決方案是使用LostFocus事件，但是，通過自定義控件顯然不會觸發它。 據我所知，經過一些研究，自定義控件沒有Focus事件，因為它們是自定義的並且可以更改（基本上，您必須自己實現focus事件）。

我的問題

是否有人解決焦點事件或解決自定義控件單擊問題的方法？

資料來源

這是我的控件的當前來源：

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

嘗試對您的自定義控件使用Enter和Leave事件。

GotFocus和LostFocus已經過時，轉而支持Enter和Leave。

更新：

由於您是從Control繼承的，因此您可能應該覆蓋事件，而不是處理它們。 MouseDown也不一定會吸引焦點，因此您也應該檢查一下：

例：

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