vb 怎么在程序运行过程中改变 richtextbox中字体的大小和颜色

vb 如何在程序运行过程中改变 richtextbox中字体的大小和颜色
rt

[解决办法]
示例：

VB code

Private Sub Command1_Click() '改变颜色和字体、大小With RichTextBox1    .SelStart = 0    .SelLength = 3    .SelColor = RGB(255, 0, 0)    .SelFontSize = 35    .SelStart = 3    .SelFontSize = 10    .SelStart = 6    .SelLength = 3    .SelColor = RGB(0, 255, 0)    .SelFontName = "楷体_GB2312"    .SelFontSize = 20End WithEnd SubPrivate Sub Form_Load()RichTextBox1.Text = "红色大黑色小绿色楷"End Sub