Any attempt to submit a duplicate value will result in an exception being raised in the relevant database provider.
You can catch this exception and show the user an appropriate message.
But first, the changes to the Register.cshtml page.
The first change is in the inclusion of a Java Script file called (which will be created a bit later): Note that the name of the folder is important. The value of the bool is determined as a result if the SQL query which gets a count of the rows containing the provided user name.
The AJAX call requests a page that exists purely to query the database to see if the selected user name is already in use.This Regional Garrison Food Service (RGFS) Contract Administration Plan (CAP) module was developed by Headquarters Marine Corps (HQMC), Installations and Logistics (I&L) (Contracts) to provide contract management guidance to contracting personnel administering the Regional Garrison Food Service Contract (RGFSC).The processes and templates included in the CAP allow for effective execution of the RGFSC, resulting in improved operational performance and management of resources.This article offers one solution to the problem that uses j Query.If you ask how to prevent duplicate user names in forums, one of the suggestions that is often put forward is to apply a unique constraint in the database column that holds the user name.The code above checks the response from the server to see if the value is a duplicate, and if it is, an appropriate error message is displayed to the user.And there it is - a clean way to provide users with immediate feedback on the availability of their chosen user name.The Web Pages Starter Site template provides a useful starting point for developing a Razor Web Pages site that includes membership.But it doesn't include any mechanism for preventing duplicate user names.I'm trying to find a way to check for a way of detecting an existing record in my SQLserver database before allowing an enter of a new record that is a duplicate. Sql Client Dim dup Count As Int16 Using conn As New Sql Connection("my Connection String") Using cmd As New Sql Command(SELECT count(*) as dup Count FROM [tbl Sales] WHERE ZIP = @ZIP AND First Name = @First Name AND Last Name = @Last Name AND Company = @Company", conn) cmd. I'm restricted from using a database index and need to do this all in and code.