我有一个注册表单。我想防止与ASP.NET.Now重复的用户名,我可以做,以防止重复的用户名。但是,我想给一个警告消息User.How我可以这样做吗?防止重复的用户名与ASP.NET
代码:
try{
SqlCommand cmd = sqlConnection.command("If not exists (Select user_name from users Where [email protected]) Insert into users(userId,user_name,user_surname,email) Values (@userID,@userName,@userSurname,@email)");
SqlParameter p1 = new SqlParameter("@userID", Session["userID"].ToString());
SqlParameter p2 = new SqlParameter("@userName", txt_userName.Text);
SqlParameter p3 = new SqlParameter("@userSurname", txt_surName.Text);
SqlParameter p4 = new SqlParameter("@email", txt_email.Text);
cmd.Parameters.Add(p1);
cmd.Parameters.Add(p2);
cmd.Parameters.Add(p3);
cmd.Parameters.Add(p4);
cmd.ExecuteNonQuery();
myConnect.close();
}
catch (Exception ex)
{
Response.Write("<script>alert("+ex.Message+ ")</script>");
}
}