Question

我设法使用图像自定义普通列表框，在ownerdrawn中选择项目时更改文本和背景颜色，我现在想要实现的是当鼠标悬停在列表框上时在项目上绘制自定义高亮颜色item，是否可能...，我在下面提供了我的示例代码到目前为止...

If e.Index = -1 Then Exit Sub
        Dim listBox As ListBox = CType(sender, ListBox)
        e.DrawBackground()
        Dim isItemSelected As Boolean = ((e.State And DrawItemState.Selected) = DrawItemState.Selected)
        If e.Index >= 0 AndAlso e.Index < listBox.Items.Count Then
            Dim textSize As SizeF = e.Graphics.MeasureString(listBox.Items(e.Index).ToString(), listBox.Font)
            Dim itemImage As Image = My.Resources.FolderHorizontal
            'set background and text color
            Dim backgroundColorBrush As New SolidBrush(If((isItemSelected), Color.CornflowerBlue, Color.White))
            Dim itemTextColorBrush As Color = If((isItemSelected), Color.White, Color.Black)

            e.Graphics.FillRectangle(backgroundColorBrush, e.Bounds)
            'draw the item image
            e.Graphics.SmoothingMode = SmoothingMode.HighQuality
            e.Graphics.DrawImage(itemImage, e.Bounds.X + 2, _
                               e.Bounds.Y + (e.Bounds.Height - textSize.Height) / 2, _
                               itemImage.Width, itemImage.Height)
            'draw the item text
            Dim x, y As Single
            Dim h As Single = textSize.Height
            Dim rect As Rectangle = e.Bounds
            rect.X += listBox.ItemHeight
            rect.Width -= listBox.ItemHeight

            x = rect.X - 3
            y = rect.Y + (rect.Height - h) / 2

            Dim itemText As String = listBox.Items(e.Index).ToString()
            TextRenderer.DrawText(e.Graphics, itemText, e.Font, _
                                  New Rectangle(x, y, ClientRectangle.Width, ClientRectangle.Height), _
                                  itemTextColorBrush, TextFormatFlags.Default)
            'clean up
            backgroundColorBrush.Dispose()

        End If
        e.DrawFocusRectangle()

Answer 1

您可以使用IndexFromPoint执行类似的操作：

Dim mouseIndex As Integer = -1

Private Sub ListBox1_MouseMove(sender As Object, e As MouseEventArgs) _
                               Handles ListBox1.MouseMove
  Dim index As Integer = ListBox1.IndexFromPoint(e.Location)
  If index <> mouseIndex Then
    If mouseIndex > -1 Then
      Dim oldIndex As Integer = mouseIndex
      mouseIndex = -1
      If oldIndex <= ListBox1.Items.Count - 1 Then
        ListBox1.Invalidate(ListBox1.GetItemRectangle(oldIndex))
      End If
    End If
    mouseIndex = index
    If mouseIndex > -1 Then
      ListBox1.Invalidate(ListBox1.GetItemRectangle(mouseIndex))
    End If
  End If
End Sub

然后在你的绘图代码中：

If mouseIndex > -1 AndAlso mouseIndex = e.Index Then
  backgroundColorBrush = New SolidBrush(Color.DarkMagenta)
End If

Answer 2

我会告诉你如何做到这一点。所有专家都说它很复杂，无法用列表框完成......我能够在5分钟内完成这项工作

我创建的列表框的名称是listPOSSIBILITIES

1）创建一个对表单而言是全局的变量

    Dim HOVERTIME As Boolean = True

2）创建MouseEnter事件

Private Sub listPOSSIBILITIES_MouseEnter（sender as Object，e as system.EventArgs）处理listPOSSIBILITIES.MouseEnter

    HOVERTIME = True

End Sub

3）创建MouseLeave事件

Private Sub listPOSSIBILITIES_MouseLeave（sender As Object，e As System.EventArgs）处理listPOSSIBILITIES.MouseLeave

    HOVERTIME = False

End Sub

4）创建MouseMove事件

Private Sub listPOSSIBILITIES_MouseMove（sender As Object，e As System.Windows.Forms.MouseEventArgs）处理listPOSSIBILITIES.MouseMove

    Dim mypoint As Point
    mypoint = listPOSSIBILITIES.PointToClient(Cursor.Position)
    Dim myindex As Integer = listPOSSIBILITIES.IndexFromPoint(mypoint)
    If myindex < 0 Then Exit Sub
    listPOSSIBILITIES.SelectedIndex = myindex

End Sub

5）创建MouseClick事件

Private Sub listPOSSIBILITIES_MouseClick（sender As Object，e As System.Windows.Forms.MouseEventArgs）处理listPOSSIBILITIES.MouseClick

    HOVERTIME = False

End Sub

6）创建SelectedIndexChanged事件

Private Sub listPOSSIBILITIES_SelectedIndexChanged（sender As System.Object，e As System.EventArgs）处理listPOSSIBILITIES.SelectedIndexChanged

    If HOVERTIME Then Exit Sub

    'put the rest of your code after this above If statement

这是有效的，因为在SelectIndexChanged事件

之前触发了MouseClick事件

鼠标悬停在项目上时突出显示列表框项目

2 个答案: