为什么.Focus()无效?解决办法

为什么.Focus()无效?
有Textbox1和Textbox2两个控件,默认启动后Textbox1会是输入状态,想弄成Textbox2是输入状态:
VB.NET code
   
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

        TextBox2.Focus()

End Sub


但是无效果,想不明白为什么.

------解决方案--------------------
将textbox2的tabIndex 改为 0
将textbox1的tabIndex 改为 1

------解决方案--------------------
private void Form1_Load(object sender, EventArgs e)
{
this.ActiveControl = this.textBox2;///加上这句就OKl
this.textBox2.Focus();
}