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Database Connection in C#

Is there a way/code where I can use that won't require me to change my connection string everytime I move my project to another computer?
been using 2 computers with different server names, but with the same database.
PC1:
static string ConnStr = "Server=DESKTOP-Q0BI1S3;Database=ISPROJ2;Trusted_Connection=True;";
PC2:
static string ConnStr = "Server=DESKTOP//SEGUERRA;Database=ISPROJ2;Trusted_Connection=True;";
tried using: Server=(localdb)
Update: used localhost and (local) with PC1 worked fine, but these won't work with PC2
see img

I am not sure if this will work for you, but where I work everyone has their own local instance of sql server and each developer are using the db on localhost. We solve this problem by referencing the database as a dot (localhost).
"Server=.;Database=ISPROJ2;Trusted_Connection=True;"
This solution only works if all developers have their db installed as the default instance.

See here.
This may be the solution you are looking for. Use the hostname and append it to the connection string.
I also believe you may be able to use server=localhost;

You could make one computer work as a server and connect to it everytime with same connection string.
This might help you:
https://technet.microsoft.com/en-us/library/ms175483(v=sql.105).aspx

There are probably lots of libraries to solve this, but the simplest way you can do interim is to within the software identify which computer the software is run on:
static string GetConnectionString()
{
switch(System.Environment.MachineName)
{
case "PC1": //TODO:Change this to the actual machine name!
return "Server=DESKTOP-Q0BI1S3;Database=ISPROJ2;Trusted_Connection=True;";
case "PC1": //TODO:Change this to the actual machine name!
return "Server=DESKTOP//SEGUERRA;Database=ISPROJ2;Trusted_Connection=True;";
}
}
You can also make it more dynamic by reading it from the web.config/app.config:
static string GetConnectionString()
{
return ConfigurationManager.AppSettings["ConnectionString_" + System.Environment.MachineName];
}
This makes it more dynamic, and you can simply add a new connection string onto the web.config/app.config once it needs to run on a new environment.
<appsettings>
<add key="connectionstring_pc1" value="[pc1connectionstringhere!]"/>
<add key="connectionstring_pc2" value="[pc2connectionstringhere!]"/>
</appsettings>

You will find all SQL Server connection string options here.
https://www.connectionstrings.com/sql-server/
Standard Security
Server=myServerAddress;Database=myDataBase;User Id=myUsername;
Password=myPassword;
Trusted Connection
Server=myServerAddress;Database=myDataBase;Trusted_Connection=True;
Connection to a SQL Server instance
The server/instance name syntax used in the server option is the same for all SQL Server connection strings.
Server=myServerName\myInstanceName;Database=myDataBase;User Id=myUsername;
Password=myPassword;

Connecting application to database on a pc over an intranet

I'm developing an application that needs to access files on computers in an intranet, the files are database files and each computer has its own database, from what i have read i need to use a //server connection string, however I want to code my application in such a way that the user selects the computer they want to retrieve the that from for example they would select "Computer 2" and the application would create the connection string, connect to the database and populate it

I would recommend creating a connection string for each machine you are accessing in the web.config file and then using the user's selection to pull the correct connection string from the config file to instantiate the connection.

I have it working with this code
string myconnectionstring = #"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=\\" + PCName + #"\data\data.mdb"

Is there a universal connection string for different computers to connect to a local database using my program developed by vs2010

newbie here.
I have a local db in my program. Whilst I was developing the program I used the SQL
Connection string :
SqlConnection sconn = new SqlConnection(#"Data Source=.\SQLEXPRESS;AttachDbFilename=C:\Users\leemk_000\Documents\......Integrated Security=True;User Instance=True;");
Now If I want to load this program onto a different computer I am sure that this connection will no longer work simply because it will still be looking for Users\Lee_000\
I have tried to remove Lee_000 but I get this following error:
An attempt to attach an auto-named database for file C:\Users\Documents..... failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
What can I do to get a connection string to work on different computers.
With many thanks

The whole User Instance and AttachDbFileName= approach is flawed - at best - especially when you want to share your database amongst multiple clients!
When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\bin\debug - where you app runs) and most likely, your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!
If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.
The real solution in my opinion would be to
install SQL Server Express (and you've already done that anyway)
install SQL Server Management Studio Express
create your database in SSMS Express, give it a logical name (e.g. YourDatabase)
connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:
Data Source=.\\SQLEXPRESS;Database=YourDatabase;Integrated Security=True
and everything else is exactly the same as before...

If it's a local db you should be placing it within the app folder and carry it with the app right?
Put the database in the App_data folder of your app and use that in your connection string
<add name="YourConnectionString" connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\yourfile.mdf;Integrated Security=True;User Instance=True" providerName="System.Data.SqlClient"/>

You need to use a database server and let your users use it via your connection string like this;
Server=myServerAddress;Database=myDataBase;User Id=myUsername;Password=myPassword;
"myServerAddress" should be the ip adress of your server machine.

Connect a C# MVC application to a remote SQL Server database

I have a SQL Server database located at http://192.168.10.3/MyDB. I have created a C# MVC application, and I need to know the steps to connect my application to the above database.
Is it only replacing the connection string in the web.config file ?
Data Source=?? ;Initial Catalog=??;Integrated Security=SSPI;
User ID=??;Password=pwd;
If so what am I to replace where I have placed the ?? sign ?

DataSource = 192.168.10.3
Initial Catalog = MyDB
User ID = whatever sql login you are using to access your SQL Server
Password = password for the sql login above

The other answers here are good. In addition, ConnectionStrings.com can be your friend, especially if you are going to connect to various types of databases in the future. Select the database that you need to connect to and then you'll see the different connection strings you can use for that database.
http://connectionstrings.com/sql-server-2012#sqlconnection

you can try this
create a new text document on your desktop - conn.txt
change file extension to udl (conn.udl)
double click to open the file in the first tab select appropriate provider
4 . in the second tab enter server name (ip address,port), username, password (check Allow saving password) and database name.
test connection
if the test reports success close the window.
open the file with notepad, copy everything but the provider name and paste it back to connectionString

Below is connection string you need for:
Data Source="192.168.10.3" ;Initial Catalog=MyDb;Integrated Security=SSPI;
User ID=sa (for example);Password=whatever you set before;

Having trouble connecting C# executable to database file on remote computer

Using VC# I've created a staff management app that, upon its first run, is expected to query the user for the path to a (.mdf) database which will reside on a remote computer. A resulting path may be something like
string dbPath = #"P:\remoteComputer\public\StaffTool\ExamplePersonnelDatabase.mdf";
Then I'm placing this string into a connection string template as so:
string dbConnectTemplate = #"Data Source=.\SQLEXPRESS;AttachDbFilename={0};Integrated Security=True;Connect Timeout=30;User Instance=True";
string dbConnectionString = String.Format(dbConnectionTemplate,dbPath);
Then I'm attempting to connect to the database LINQ to SQL style
ManagementDBDataContext db = new ManagementDBDataContext(
dbConnectionString);
At this point, an error pop's up stating that
The file "P:\remoteComputer\public\StaffTool\ExamplePersonnelDatabase.mdf" is on a network path that is not supported for database files.
An attempt to attach an auto-named database for file P:\remoteComputer\public\StaffTool\ExamplePersonnelDatabase.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
As I am relatively new to databases, I completely do not understand this message. And obviously, the file is not on a UNC share.
Any ideas?
Jim Lamb recommended that I connect to an instance of SQL server running remotely. Considering that I'm using LINQ to SQL, what refactoring do I have to do to make this happen? Other ideas still welcome - especially "push this button and everything will work" solutions.
Another clue: A coworker said that there used to be some way to work through Control Panel->Administrative Tools->Data Sources(ODBC) so that a remote database could be viewed from my computer as if it was local. The coworker didn't know any more details besides this.

You are attempting to connect to a database file on another machine over a network connection, which isn't supported by SQL Express. You'll need to make a local copy and attach to that, or connect to an instance of SQL that's running on the same machine as the MDF file.