tabcontrol的alignment属性设置成Left或Right时，tabPage的text内容不能显示的问题

VB.net >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

Private tabArea As Rectangle
Private tabTextArea As RectangleF

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Me.TabControl1.DrawMode = TabDrawMode.OwnerDrawFixed '设置用户绘制方式
Me.TabControl1.Alignment = TabAlignment.Right '设置TAB项右对齐布局
'TabControl1.SizeMode = TabSizeMode.Fixed ‘设置TAB项大小的方式（全都一样大小）
'TabControl1.ItemSize = New Size(150, 20) '设置大小
End Sub

Private Sub TabControl1_DrawItem(ByVal sender As Object, ByVal e As System.Windows.Forms.DrawItemEventArgs) Handles TabControl1.DrawItem
tabArea = TabControl1.GetTabRect(e.Index) '主要是做个转换来获得TAB项的RECTANGELF
tabTextArea = RectangleF.op_Implicit(TabControl1.GetTabRect(e.Index))
Dim g As Graphics = e.Graphics
Dim sf As New StringFormat() '封装文本布局信息

sf.LineAlignment = StringAlignment.Center
sf.Alignment = StringAlignment.Center

Dim p As New Pen(Color.Blue) '绘制边框的画笔
Dim font As New Font("Arial", 10.0F)
Dim brush As New SolidBrush(Color.Red)

g.DrawRectangle(p, tabArea) '绘制边框
'绘制文字
g.DrawString(CType(sender, TabControl).TabPages(e.Index).Text, font, brush, tabTextArea, sf)
End Sub

C#.net>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

private Rectangle tabArea;
private RectangleF tabTextArea ;

private void frmopen_Load(object sender, System.EventArgs e)
{
this.tabControl1.DrawMode = TabDrawMode.OwnerDrawFixed;
}

private void tabControl1_DrawItem(object sender, System.Windows.Forms.DrawItemEventArgs e)
{
tabArea = tabControl1.GetTabRect(e.Index);

tabTextArea = tabArea;

Graphics g = e.Graphics;

StringFormat sf = new StringFormat();

sf.LineAlignment = StringAlignment.Center;

sf.Alignment = StringAlignment.Center;

Font font = this.tabControl1.Font ;

SolidBrush brush = new SolidBrush(Color.Black);

g.DrawString(((TabControl)(sender)).TabPages[e.Index].Text, font, brush, tabTextArea, sf);
}