protected void Button1_Click(object sender, EventArgs e)
{
Userinfo us = new Userinfo();
if (us.checkname(TextBox1.Text))
{
Response.Write("<script>alert('该用户已存在，无法添加');</script>");
}
else
{
us.createUser(TextBox1.Text);
Response.Redirect("usermng.aspx");
}
}