UWP the application cannot communicate with the remote instance SQL Server

Question

I am currently implementing a UWP program for an existing database. I took this article as a basis. https://learn.microsoft.com/en-us/windows/uwp/data-access/sql-server-databases

When running, I get an exception:

System.Data.SqlClient.SqlException" в System.Data.SqlClient.dll

Exception:
A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: TCP Provider, error: 25 - Connection string is not valid)

This seemed strange to me, since a WPF application with the same connection string works fine. Next, I decided to install a database instance on my computer and export some of the data to a local database. To my surprise, after replacing the connection string from:

Data Source=sqlserver\sqlexpress

to

Data Source=.\sqlexpress

UWP program read this from the database on my computer.

I also read this article to make sure that the remote database is configured correctly. https://www.lansweeper.com/knowledgebase/a-network-related-or-instance-specific-error-occurred/

As I said, WPF programs work with this database perfectly. What are the ways to check why the UWP doesn't want to communicate with the database?

to make it clear whether the remote server is available in principle, I apply the output of the TNC command:

tnc sqlserver -p 1433 -I detailed


ComputerName            : sqlserver
RemoteAddress           : 192.168.10.11
RemotePort              : 1433
NameResolutionResults   : 192.168.10.11
MatchingIPsecRules      :
NetworkIsolationContext : Private Network
InterfaceAlias          : Ethernet
SourceAddress           : 192.168.10.20
NetRoute (NextHop)      : 0.0.0.0
TcpTestSucceeded        : True

Connection string look like:

private string connectionString = @"Data Source=sqlserver\sqlexpress;Initial Catalog=TestCatalog;User ID=*;Password=*";

The same connection string is used in VS. VS shows the contents of the table without problems. I can also delete or add new lines in the VS editor.

I'm talking about a remote database. In VS server Explorer I have a Data Connection where I am connected to a remote database. I can safely edit remote database data in VS (add, delete and update). I see the connection string and originally used it as the connection string in UWP app.

Answer 1

You have already taken a look at this microsoft link here. Long story short, have you followed the proposal below?

Trouble connecting to your database? In most cases, some aspect of the SQL Server configuration needs to be changed. If you're able to connect to your database from another type of desktop application such as a Windows Forms or WPF application, ensure that you've enabled TCP/IP for SQL Server. You can do that in the Computer Management console.

Check to see if you have followed the rest of the solution properly. You might need to enable the tcp port from the window firewall.

Go to firewall -> Inbound Rules -> Add TCP:1433 in the rule.

Also since the error is about the connection string, try to use only the server name/ ip/ or hostname, without the server instance.

You can also add the port number and see if this works for you. When you add it, sql server ignores the instance name (as different instances require different ports to work, so it can work as a unique identifier).

Edit: How to create a valid connection string:

Look at this answer here: How to get the connection String from a database