我有一個註冊表單。我想防止與ASP.NET.Now重複的用戶名,我可以做,以防止重複的用戶名。但是,我想給一個警告消息User.How我可以這樣做嗎?防止重複的用戶名與ASP.NET
代碼:
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>");
}
}