vb.net - VB.NET：图像作为复选框状态框

Question

是否可以使用图像作为复选框“选中”指示方块？

我知道我可以使用背景图像，但这也位于标签后面，而且（据我所知）不可能对齐它。

如何使用图像而不是正方形并保留标签和所有其他自定义项？

提前致谢！

Answer 1

你看起来像这样？

Dim frm As New Form
frm.Size = New Size(320, 200)

Dim iList As New ImageList
iList.Images.Add(Image.FromFile("check.png"), Color.White)
iList.Images.Add(Image.FromFile("uncheck.png"), Color.White)

Dim chk As New CheckBox
chk.Text = "Check Box With Image"
chk.AutoSize = False
chk.Size = New Size(350, 20)
chk.ImageList = iList
chk.ImageIndex = 1
chk.CheckAlign = ContentAlignment.MiddleRight
chk.ImageAlign = ContentAlignment.MiddleLeft
chk.TextImageRelation = TextImageRelation.ImageBeforeText
chk.Location = New Point(32, 32)

frm.Controls.Add(chk)

AddHandler chk.CheckStateChanged,
    Sub(sender1 As Object, e1 As EventArgs)
        chk.ImageIndex = IIf(chk.Checked, 0, 1)
    End Sub

frm.ShowDialog()

Answer 2

更新#1：实际上，@brahm 下面的解决方案比我的要好得多！

更新＃2：实际上，它不是。现在我看到了他是如何做到的：他将复选框移到了可见Form区域之外。不是一个很好的解决方案...

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理想的解决方案是对控件进行子类化并通过覆盖该方法CheckBox进行自己的渲染。OnPaint

一个更简单但可能更混乱的解决方案是在复选框上放置一个 PictureBox 并PictureBox通过CheckBox'CheckedChange事件控制图像。

另一种选择：您仍然可以按照您的建议使用CheckBox按钮模式 ( Appearance = Button)，但随后在其旁边添加一个标签。然后，处理ClickLabel 上的事件以切换CheckBox. 然后最终结果应该为您提供您正在寻找的东西。

Answer 3

Imports System.Drawing
Imports System.Windows.Forms
Imports System.Windows.Forms.VisualStyles

Public Class ImageCheckBox

  Public State As CheckBoxState = CheckBoxState.UncheckedNormal
  Public Hot As Boolean = False
  Public Pressed As Boolean = False
  Public ImageDictionary As Dictionary(Of CheckBoxState, Image) = New Dictionary(Of CheckBoxState, Image)
  Private Const PaddingModifier As Integer = 2

  Sub New()
    Me.New(New Dictionary(Of CheckBoxState, Image) From {
      {CheckBoxState.CheckedDisabled, My.Resources.form_checkbox_checked},
      {CheckBoxState.CheckedHot, My.Resources.form_checkbox_checked},
      {CheckBoxState.CheckedNormal, My.Resources.form_checkbox_checked},
      {CheckBoxState.CheckedPressed, My.Resources.form_checkbox_checked},
      {CheckBoxState.UncheckedDisabled, My.Resources.form_checkbox_unchecked},
      {CheckBoxState.UncheckedHot, My.Resources.form_checkbox_unchecked},
      {CheckBoxState.UncheckedNormal, My.Resources.form_checkbox_unchecked},
      {CheckBoxState.UncheckedPressed, My.Resources.form_checkbox_unchecked}})
  End Sub

  Sub New(imageDictionary As Dictionary(Of CheckBoxState, Image))

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.


    Me.ImageDictionary = imageDictionary
  End Sub

  Sub CheckBox_Paint(sender As Object, e As PaintEventArgs) Handles Me.Paint
    'Return if the specific Image is not found
    If Not ImageDictionary.ContainsKey(State) Then Return

    'Get the Size of the CheckBox
    Dim glyphSize As Size = CheckBoxRenderer.GetGlyphSize(e.Graphics, State)

    'Get the Location of the CheckBox in relation to the Alignment of it
    Dim glyphLocation As Point
    Select Case Me.CheckAlign
      Case Drawing.ContentAlignment.TopLeft
        glyphLocation = New Point(Me.Padding.Left, Me.Padding.Top)
        Exit Select
      Case Drawing.ContentAlignment.TopCenter
        glyphLocation = New Point(Me.Padding.Left + (Me.Width - glyphSize.Width) / 2, Me.Padding.Top)
        Exit Select
      Case Drawing.ContentAlignment.TopRight
        glyphLocation = New Point(Me.Padding.Left + Me.Width - glyphSize.Width, Me.Padding.Top)
        Exit Select
      Case Drawing.ContentAlignment.MiddleLeft
        glyphLocation = New Point(Me.Padding.Left, Me.Padding.Top + (Me.Height - glyphSize.Height) / 2)
        Exit Select
      Case Drawing.ContentAlignment.MiddleCenter
        glyphLocation = New Point(Me.Padding.Left + (Me.Width - glyphSize.Width) / 2, Me.Padding.Top + (Me.Height - glyphSize.Height) / 2)
        Exit Select
      Case Drawing.ContentAlignment.MiddleRight
        glyphLocation = New Point(Me.Padding.Left + Me.Width - glyphSize.Width, Me.Padding.Top + (Me.Height - glyphSize.Height) / 2)
        Exit Select
      Case Drawing.ContentAlignment.BottomLeft
        glyphLocation = New Point(Me.Padding.Left, Me.Padding.Top + Me.Height - glyphSize.Height)
        Exit Select
      Case Drawing.ContentAlignment.BottomCenter
        glyphLocation = New Point(Me.Padding.Left + (Me.Width - glyphSize.Width) / 2, Me.Padding.Top + Me.Height - glyphSize.Height)
        Exit Select
      Case Drawing.ContentAlignment.BottomRight
        glyphLocation = New Point(Me.Padding.Left + Me.Width - glyphSize.Width, Me.Padding.Top + Me.Height - glyphSize.Height)
        Exit Select
    End Select

    'Set the drawing Area
    Dim glyphRectangle As Rectangle = New Rectangle(glyphLocation, glyphSize)

    'Enlarge the Rectangle to completely hide default symbol
    Dim clearRectangle As Rectangle = New Rectangle(glyphLocation.X - PaddingModifier,
                                                    glyphLocation.Y - PaddingModifier,
                                                    glyphSize.Width + 2 * PaddingModifier,
                                                    glyphSize.Height + 2 * PaddingModifier)

    'Draw the Parent Background over the default CheckBox to clear it
    CheckBoxRenderer.DrawParentBackground(e.Graphics, clearRectangle, Me)

    Debug.WriteLine(State)
    'Finally draw the custom CheckBox image on the position of the default one
    e.Graphics.DrawImage(ImageDictionary(State), glyphRectangle)
  End Sub

  Sub CheckBox_MouseClick(sender As Object, e As EventArgs) Handles Me.MouseClick
    Me.Checked = Not Me.Checked
  End Sub
  Sub CheckBox_MouseDown(sender As Object, e As MouseEventArgs) Handles Me.MouseDown
    Me.Pressed = True
  End Sub
  Sub CheckBox_MouseUp(sender As Object, e As MouseEventArgs) Handles Me.MouseUp
    Me.Pressed = False
  End Sub
  Sub CheckBox_MouseEnter(sender As Object, e As EventArgs) Handles Me.MouseEnter
    Me.Hot = True
  End Sub
  Sub CheckBox_MouseLeave(sender As Object, e As EventArgs) Handles Me.MouseLeave
    Me.Hot = False
  End Sub

  Public Sub updateState() Handles Me.MouseClick, Me.MouseDown, Me.MouseUp, Me.MouseEnter, Me.MouseLeave, Me.EnabledChanged
    Debug.WriteLine(Me.Checked & " " & Me.Enabled & " " & Me.Hot & " " & Me.Pressed)
    Me.State = CurrentState()
    Me.Refresh()
    Debug.WriteLine(State)
  End Sub

  Public Function CurrentState() As CheckBoxState
    If (Me.Checked) Then
      If (Not Me.Enabled) Then Return CheckBoxState.CheckedDisabled
      If (Me.Pressed) Then Return CheckBoxState.CheckedPressed
      If (Me.Hot) Then Return CheckBoxState.CheckedHot
      Return CheckBoxState.CheckedNormal
    Else
      If (Not Me.Enabled) Then Return CheckBoxState.UncheckedDisabled
      If (Me.Pressed) Then Return CheckBoxState.UncheckedPressed
      If (Me.Hot) Then Return CheckBoxState.UncheckedHot
      Return CheckBoxState.UncheckedNormal
    End If
  End Function

End Class