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I want to create a shared database c# windows form application?

This application that i am trying to create, whose "instances/copies" will be installed on multiple PCs of the client and are able to access the same database from another PC of the same client that has SQL server running all the time through the same network(i.e: they have the same router and static IP of server etc).
I had two ways to do this:
To make applications use the same database through synchronization.
To have multiple localdbs that then share the changes a database server.
By following 1st way,
I tried setting up the Connection String like:
SqlConnection con = new SqlConnection("Data Source =[serverPcIP,Port];Integrated Security=True;Connect Timeout=30");
SqlConnection con = new SqlConnection("SERVER=[serverPcIP]; Port=[portno];Integrated Security=True;Connect Timeout=30");
In Server - Security Settings:
I have allowed "SQL Server and Windows Authentication mode"
In Sql Server Configuration Manager > SQL Server Network Configuration > Protocols for SQLEXPRESS => TCP/IP = Enabled; under IP Addresses -> IP1 -> TCP Port = 1433 (port that i used in my connection-string)
In advanced Firewall Setting:
Have enabled the Incoming & Outgoing rules for port 1433.
The exception that i get:
Additional information: 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: 0 - The wait operation timed out.)
Can someone please tell me what configurations (either in connection-String or in SQL server itself) am i missing?

Your connection string lacks the instance name e.g. data source=<hostname or ip>\SQLEXPRESS. If your database listens on the default port 1433 you don't need to pass that with the connection string
If you setup a SQL server, you can choose between the default SQL Server instance or the named instance. For SQL Express the default is to install a named instance with the name SQLEXPRESS. If you don't use the default instance and install a named instance instead, you have to pass it with the connection string.
The default SQL Server instance ist just a named instance with the well known name MSSQLSERVER. So if you installed the database instance as the default instance you can connect with <host>[,port] or <host>\MSSQLSERVER[,port]

based on your screenshot, under IP1, the ip address is active but not enabled.
also, ip address that starts with 169.x.x.x normally would mean you have set up this network card to use DHCP, but the network card failed to have ip address from the DHCP server.
do you mind try to use static ip address?

Consider following steps:
Since you mention the port number using configuration manager, the service required restart. please restart the service if not done so.
Seems you are able to connect via SSMS, once service restarted verify SQL Error log via SSMS -> Managemnt -> SQL Server Logs, you must find a message as follows:
Server is listening on [ 'any' <ipv4> 1433].
Further details, follow these steps. Also, this..

Unable to form connection ASP.NET network path

EDIT #1: The server is listening on port 1434 and I am looking at the TCP Port in the properties of TCP/IP Properties in Sql Server Configuration Manager and it says port 1433. Could this be the problem?
I have been at this for hours and I have tried many different questions and read through many different questions and answers as well as many other forums.
https://www.youtube.com/watch?v=1k00z82u4OI This video has answers which I tried.
In Visual Studio I am able to test the connection to my Database in Sql Server and it succeeds as well as provides me with the connection string for my SqlConnection object.
My server is listening on port 1434.
In Sql Server Configuration Mananger I have Shared Memory, (Named Pipes and TCP/IP enabled. I restarted SQL Server Browser, SQL Server (MSSQLSERVER), SQL Server Agent and they are running.
In Visual Studio my Data Connections is connected to my server and database and the State is Open.
My connection string looks like this (minus the actual characters of my server):
SqlConnection sqlCon = new SqlConnection("Data Source = DESKTOP - #######; Initial Catalog = ASPCRUD; Integrated Security = True;");
Error message includes:(provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)]

SQL Server problems to connect

I am developing a program with C# and WPF. I want the data to be stored in an SQL Server database. I made a connection string with the instance name in my PC, and that worked. But when I want to connect through the Internet with an IP address, I get some errors:
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. (TCP Provider,
error 0 - No connection could be made because the target machine
actively refused it.)
I enabled TCP/IP, allowed remote connection in SQL Configuration Manager, opened a port of 1433 in my firewall, but still I am getting this error.
My connection string is this:
String connString = #"Network Library=dbmssocn;
Network Address=127.0.0.1,1433;
Integrated security=SSPI;
Initial Catalog=db";
SqlConnection conn = new SqlConnection(connString);
conn.Open( );
Where is my mistake?

There is very slight error in your connection string and honestly I can't blame you for that as it is very weird way in which SQL Sever is behaving. I'm not sure if this error lies in connection provider side or SQL Server instance side. Name of Network Library that your application is using to connect to the SQL Server using dbmssocn(Win32 Winsock TCP/IP) should always be mentioned in capital letters. Though I didn't see any relevant MSDN documentation from MS to support my statement but it actually worked when I did so. Here is the connection string that you should be using to fix the error.
String connString = #"Network Library=DBMSSOCN;
Network Address=127.0.0.1,1433;
Integrated security=SSPI;
Initial Catalog=db";
Seriously, I got freaked out in reproducing your issue as instead of copying the connection string from your question I copied it from some other blog :). But all is well that ends well. I've also assumed that a database named "db" actually exists on the default (NOT named instance) instance of the sql server you are connecting to when typing this answer. If changing the casing of network library name in connection string doesn't help then double check that database "db" must exist for a sql server default instance to which you are connecting to. In case you are using a named instance of sql server in your installation then that instance name should also come in the connection string.

Configure your SQL Server to allow TCP/IP connections. Go to SQL Server Configuration Manager -> network then protocols for your SQL Server named instance -> TCP/IP.
See this image!

SQL Server Connection Issue - I can connect but other users can't

[edit] so not sure what happened, but we ended up resetting the server and turning off/on TCP/IP and Named Pipes and after a restart and updating the settings everything started working again. weirdest thing. anyways thanks for the help guys.
I'm building a C# WPF application for my job, and I'm getting a weird problem that I've been trying to figure out for the past week. The application connects to the server and imports several tables on start up. So I built it out and was testing it with no issues, but when i pass it to our testers, and everyone is getting the following errors:
Provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server
The users are able to connect to the server through other methods (SSMS/Excel VBA), but just through the application it won't work.
I've checked the following:
Remote connections enabled
TCP/IP connections enabled
Firewall settings are the exact same across all users (me included)
application is compiled as 32 bit (saw this in another thread)
We're using SQL Server 2008 and I've tried several connection strings/methods.
below is the code I'm using to connect:
public void Open_DB_Conn(string Connection_Str)
{
try
{
Sql_Conn = new SqlConnection(Conn_Str);
Sql_Conn.Open();
}
catch (Exception e)
{
MessageBox.Show(string.Format("Error Message:{0} Conn String: {1}",e.Message,Conn_Str));
}
}
Below is my connection string (this is just one of many iterations I've used trying to get it working):
Data Source=IP Address;Initial Catalog=DB_Name;User ID=LOGIN;Password=PWD
Anyone know why I would be the only one able to get it to work and that the users are able to login to the server using other applications without a problem? They use it for logging their excel VBA scripts and there aren't any issues there.

Try this - it may be your answer
"The error is reported by client library. While your server is listeing on remote TCP, client will still try TCP and NP connection in order. So the error client behavior is expected. From what you have described, I believe that even though you enabled the remote TCP connection on the XPSP2 machine, you didn't make the TCP listening port an exception of XPSP2 personal firewall. You should follow steps below to resolve this issue.
check the SQL Server Errorlog to make sure SQL Server is now listening on TCP/IP and confirm which port it is listening on. Usually 1433. In the Errorlog, you will see several lines that discuss what SQL Server is listening on. Below is an example:
2006-01-04 01:41:07.65 server SQL server listening on 10.254.1.150: 1433. <--Shows the IP Address and the port.
2006-01-04 01:41:07.65 server SQL server listening on 127.0.0.1: 1433. <--Shows another IP Address and the port.
2006-01-04 01:41:07.69 server SQL server listening on TCP, Shared Memory, Named Pipes.
2006-01-04 01:41:07.69 server SQL Server is ready for client connections
2, Make sure on Windows XP that the firewall is not blocking that port.
3, go to your client machine and run the client network configuration tool (cliconfg.exe) Make sure TCP/IP is enabled, click properties and make sure the port number is the same one as SQL Server is listening on. Here you can enable NP or disable client NP as well.
Once both the client and the server are using TCP/IP with the same port number and the firewall on server machines is not blocked, you should be able to connect.
Hope this helps."
(Ref: http://social.technet.microsoft.com/Forums/sqlserver/en-US/c488cf76-2515-440f-b3f8-9cfad689c5b6/named-pipes-provider-error-40-could-not-open-a-connection-to-sql-server?forum=sqldataaccess)

You have to configured your SQl server so that other IP can connect it for that you have to gone through mentioned link
Configure SQL server

What authentication are you using for the SQL Server? Windows Authentication or SQL Server authentication? My suggestion is to first turn on SQL Server authentication and use the sa\password to connect to the server. If you are successful, then ask the others (users of your application) to try with the same connection string. Let me know what you find out.

Be sure that the port specified in:
Data Source="IPAddress,port";Initial Catalog=DB_Name;User ID=LOGIN;Password=PWD
matches the port on your SQL Server. You can check that by going on SQL Server COnfiguration Manager and viewing TCP/IP properties.
EDIT :
It is also the case the port defined by blocked by an external firewall. And the rest Applications use other ports. Try to find out which port you can use (if indeed the are restrictions to your network)

Make sure your SQL Server instance is properly configured to use TCP using Sql Server Configuration Manager.
It is by default disabled in SQL Express, as show below.

I'd like to know more about your "Sql_Conn" class.
Also, try using this for your connection.
using (var conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString))
{
conn.Open();
using (var cmd = conn.CreateCommand())
{
string cmdText = "SELECT name FROM sys.tables"
cmd.CommandText = cmdText;
cmd.ExecuteNonQuery();
}
}

Test Connectivity of SQL Server from remote machine using C#

I need to test the connectivity of SQL Server with my remote machine,
I have SQL server name not IP address.
How can I check this connectivity.
How will I know on which port the communication enabled.

You need to try to connect, there is no way find on which port someone is listening without directly asking, hey, is there anyone on this port?
Here is the way to do so from C#:
TcpClient tc = null;
try
{
tc = new TcpClient("MyAddress", MyPort);
// port is open
}
catch(SocketException se)
{
// port is not open, or host is not reachable
}
finally
{
tc.Close();
}

Well you must know on which port the Sql server services are listening on remote server. Default port is 1433.
If you want to test if a port is open on a server or not then you can try Telnet ping.
open command prompt:
C:\> Telnet <YourServername> <portno.>
If it's open then a screen will go empty immediately or return an error.

You need to know the IP address or host name of the server and the TCP port, too. The instance name alone won't help, as they are not advertised on the network. If you have the server's name or IP and the SQL Server instance name, you can simply try to connect using an SqlConnection with an appropriate connection string. If you can connect, everything's fine.