VB.NET ToolStripItem.Placement属性代码示例

' This method defines the behavior for rendering the
' background of a ToolStripItem. If the item is a
' RolloverItem, it paints the item's BackgroundImage 
' centered in the client area. If the mouse is in the 
' item's client area, a border is drawn around it.
' If the item is on a drop-down or if it is on the
' overflow, a gradient is painted in the background.
Protected Overrides Sub OnRenderItemBackground(ByVal e As ToolStripItemRenderEventArgs)
    MyBase.OnRenderItemBackground(e)

    Dim item As RolloverItem = CType(e.Item, RolloverItem)

    ' If the ToolSTripItem is of type RolloverItem, 
    ' perform custom rendering for the background.
    If (item IsNot Nothing) Then
        If item.Placement = ToolStripItemPlacement.Overflow OrElse item.IsOnDropDown Then
            Dim b As New LinearGradientBrush(item.ContentRectangle, Color.Salmon, Color.DarkRed, 0.0F, False)
            Try
                e.Graphics.FillRectangle(b, item.ContentRectangle)
            Finally
                b.Dispose()
            End Try
        End If

        ' The RolloverItem control only supports 
        ' the ImageLayout.Center setting for the
        ' BackgroundImage property.
        If item.BackgroundImageLayout = ImageLayout.Center Then
            ' Get references to the item's ContentRectangle
            ' and BackgroundImage, for convenience.
            Dim cr As Rectangle = item.ContentRectangle
            Dim bgi As Image = item.BackgroundImage

            ' Compute the center of the item's ContentRectangle.
            Dim centerX As Integer = CInt((cr.Width - bgi.Width) / 2)
            Dim centerY As Integer = CInt((cr.Height - bgi.Height) / 2)

            ' If the item is selected, draw the background
            ' image as usual. Otherwise, draw it as disabled.
            If item.Selected Then
                e.Graphics.DrawImage(bgi, centerX, centerY)
            Else
                ControlPaint.DrawImageDisabled(e.Graphics, bgi, centerX, centerY, item.BackColor)
            End If
        End If

        ' If the item is in the rollover state, 
        ' draw a border around it.
        If item.Rollover Then
            ControlPaint.DrawFocusRectangle(e.Graphics, item.ContentRectangle)
        End If
    End If
End Sub