主题：正则表达式

Dim data As String = e.Form.Controls("TextBox1").text

Dim reg As new System.Text.RegularExpressions.Regex("^[0-9a-zA-Z]+$")

Dim result As Boolean = reg.IsMatch(data)

If result = False Then

    e.Sender.Error = "输入的格式不正确,用户名只能为字母或数字,请重新输入!"

    e.Form.Controls("TextBox1").text = ""

Else

    e.Sender.Error = ""

End If