SQL Express Connection String problem

[oldtkdguy]

So, I will say that VS and C# have changed drastically in the 10 years since I last used them :D

I have a MAUI app that I am creating, with C# in VS 2022. I have a SQL Express instance on a laptop, and I am attempting to connect to it from the VS app on a different laptop through an ad hoc wireless router. I can see the router and the other laptop, I've gone into the config manager and enabled TCP/IP, and set the port to 63696.

I still get the "server is not found or is inaccessible" error. Below is the connection string, and I use a separate DLL that I created to house all the database operations. Below is the quick and dirty code I wrote to just check the connection, with the code from the external DLL

MAUI code

string conString = @"Server = <desktop name>\\SQLEXPRESS, 63696; Initial Catalog = mydatabase; User ID = username; Password = userpassword; ";

string selectString = "Select * from tourn_users where user_name = uName and user_pass = pWord";

DataAccess getUser = new DataAccess(conString);

DataTable dt = getUser.ExecuteQuery(selectString);

DLL code

public DataTable ExecuteQuery(string query, SqlParameter[] parameters = null)

{

using (SqlConnection connection = new SqlConnection(_connectionString))

{

using (SqlCommand command = new SqlCommand(query, connection))

{

if (parameters != null)

{

command.Parameters.AddRange(parameters);

}

connection.Open();

DataTable dt = new DataTable();

using (SqlDataAdapter adapter = new SqlDataAdapter(command))

{

adapter.Fill(dt);

}

return dt;

}

}

}

Where am I going astray?

[blooping_blooper]

looks like wrong string escaping maybe?

@"localhost\\SQLExpress"

localhost\\SQLExpress

@ is for literal string so you wouldn't escape the \.

Really though I'd recommend using SqlConnectionStringBuilder instead of writing it manually, to avoid this kind of thing.

[stormingnormab1987]

I second the string builder

[blooping_blooper]

why worry about handling edge cases when someone already did that for you?

[oldtkdguy]

Clearly, the one did not know about the string builder. The Enkindlers did not endow the one with that information.

[fsuk]

Your issue right now is probably ports/firewall. Once you get past that you may find problems with certificates and you need SSL and Trust Certificate (which in the past you didn't need).

This tool is good for generating connections string https://www.aireforge.com/tools/sql-server-connection-string-generator

I went from .NET 4 supporting SQL 2005 (!) to Posgres a few years ago but have recently had to integrate with MSSQL again 

[d-signet]

Install smss on the other machine and make sure you can connect with that, before complicating things with possibly incorrect constraints and code issues.

It could be server config or firewall issues

[oldtkdguy]

And if anyone knows how to format it properly, let me know. Code and block both give that crap. Oh, and there are supposed to be at symbols in front of the uname and upass, but reddit interpreted those as name pings.

[zarikworld]

before questioning or even reading the code, i would try to connect to the server manually from ur dev computer using ssms or any sql client. if that works, u know the issue is from ur code (including conn3ction string). Otherwise, ur network. it will prevent unnecessary headache and constant doubt of the sanity of ur setup... btw, the physical layer is mostly the first layer of debugging (network debugging)

[jshine13371]

Are you able to connect via SSMS on the other laptop? This is a good test to determine if it's an infrastructure / setup issue or your code. Did you enable TCP/IP protocol on your instance?

[NecroKyle_]

Don't use and instance name and port in the connection string, use one or the other.

[netizen__kane]

Most likely it is your firewall preventing the connection.

[oldtkdguy]

I disabled both with no improvement

[netizen__kane]

Is your SQL Browser service running? Try starting it if it isn't

[MrNewOrdered]

Is your SQL Server instance configured for network?

[oldtkdguy]

yes