We Keep Coding

A network related or instance specific error only in my machine

I am getting the below error when I try to connect to SQL server from C# code
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: SQL
Network Interfaces, error: 26 - Error Locating Server/Instance
Specified)
My connection String looks like this
"Data Source={DatabaseServer};Initial
Catalog={DatabaseName};Integrated Security=SSPI;Enlist=false;"
I have tried all the option which I found in lots of articles but could not solve the issue. One more thing to note is my colleague is able to run the same code from his machine. So it is obviously not problem with SQL server. It has to do something with my machine.can anyone give me any pointers what could be the problem? I am able to connect to SQL server instance through SSMS.

What is the provider in your connection string? Something like
Data Source=SQLServerName;Initial Catalog=DatabaseName;Provider=SQLNCLI11.1;Integrated Security=SSPI;

Well I figured it out...Actually I am working on a remote machine and I created a new project in visual studio which gets created in remote drive by default. so it does not seems to find instance from remote drive but it works when I copy it to my local drive..

Since you can connect to your SQL server through SSMS and the error message looks like the connection string is wrong (or only working for some people somehow), you could compare the parameters SSMS uses in the connection dialog to those in your connection string in the C# code.
If you find any differences there, they could be the error you're looking for.

Connection to SQL Server Express from Visual Studio

I created a database using SQL Server Express from Visual Studio 2012 and I fail to open a connection pointing that database.
I've tried many way like for example:
SqlConnection connectionLocale = new SqlConnection(#"Data Source=(LocalDB)\\v11.0;AttachDbFilename=C:\Users\Max\Desktop\presentoir\Application\WpfAppTest\BDD.mdf;Integrated Security=True");
But I keep on getting the same error message :
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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server) (Microsoft SQL Server, Error: 1326)
As I am a total beginner, even with two days of research, I really can't figure out what the problem is.
I can get a connection using :
SqlConnection connectionLocale = new SqlConnection("Data Source=(LocalDB)\\v11.0;AttachDbFilename=|DataDirectory|BDD.mdf;Integrated Security=True");
But I can't change my database using C# code by connecting like this (I think it creates a temporary database in appdata, and that all the modifications are done in this database).
Every idea helping me to create a connection to my database is welcome.

Okay, a coworker found the solution.
God, it was obvious...
With the # behind the string, the correct data source was :
#"Data Source=(LocalDB)\v11.0
and not :
#"Data Source=(LocalDB)\\v11.0

Error - "The server was not found or was not accessible" when trying to connect to sql server database

I'm working on a local project and trying to connect to a local database.
I have this class in it the connection string:
public class SQLConnection
{
public static string connectionString =
#"Data Source=TZVIKA-PC\SQLEXPRESS;Initial Catalog=WorldCup;Integrated Security=True";
public static WorldCupDBDataContext wcDataContext =
new WorldCupDBDataContext(connectionString);
public static WorldCupDBDataContext GetDataContextInstance()
{
return wcDataContext;
}
}
when I try to execute this line in a windows form:
teamBindingSource.DataSource = database.Teams.OrderBy(team => team.TeamId);
I get the following sql 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: SQL
Network Interfaces, error: 26 - Error Locating Server/Instance
Specified)
My friend ran the code and it works on his pc(when changing the connection string of course to a relevant one)
Why is it not working for me?

A good (and easy) way to test if your SQL connection is working is to use a .UDL file. Simply create an empty text (.txt) file on your desktop and rename the extension to .udl. Double click and you'll be presented with a SQL connection window, fill in the details, test connection and then (when it's working) save. Close the window and rename the file extension to .txt. Open and inside you'll find your working connection string.

Enable remote connections for SQL Server Express 2012
Most common problems are:
1) Your sql server express is not running. Check it in "sql server configuration manager"
2) server runs but don't allow remote connection. Use sql management studio to configure it.

Connecting to a SQL Database

I am using Visual Studio and trying to connect to the Northwind database. I use the following connection command...
Data Source=C:\\Program Files (x86)\\Microsoft SQL Server Compact Edition\\v3.5\\Samples\\Northwind.sdf;Initial Catalog=Northwind;Integrated Security=SSPI"
I have also tried
Data Source=(local);Initial Catalog=Northwind;Integrated Security=SSPI
both cases I get an error -
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: SQL
Network Interfaces, error: 26 - Error Locating Server/Instance
Specified)
I can connect to an online database but not on a remote one. I have checked the config manager and all services are running.
Any helps please

there are lots of collections of connection strings so you can get help from here...
http://www.connectionstrings.com/sql-server-2008

The Visual Studio has tools to connect to databases. Using Server Explorer, you can choose which SQL Server you want to connect to and then choose the database from a list. Once you have successfully connected to one, its properties mention the connection string to use. No need to guess.

Sql Connection Problem

I have a sqlconnection problem. i have perfectly connection to sql server when i m using sqldatasource.
but when i m try use SqlConnection object throw an exception.
string qstring = "Data Source=****;Initial Catalog=**;User ID=**;Password=**";
SqlConnection con = new SqlConnection(qstring);
con.Open(); (exception thrown here)
exception is : 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: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
Sql server is in different machine and i can connect using SqlDataSource object for example i can bind a grid by that way. But i must connect with SqlConnection object
Connection string is true because i have it from SqlDataSource...
Thx for your helps..

You might also want to make sure that the SQL Server is set up to accept remote connections.
(for sql2005 Configuration tools -> Surface AreaConfiguration-> Services and Connections -> database, Local and remote connections )

Is your SQL server is in the same machine ? if yes , Check the SQL server service is running , If its in a different machine,check your development machine has connectivity to it .You can ping to that machine to verify this. You can also check the surface area connection wizard to check whether the SQL server support remote connections , as snomag said

If the code that you have shown is what you have then I'm not surprised that you couldn't connect.
You'll need to have the correct Data Source, UserID and Password in qstring. As it stands asterisk characters won't mean anything.
A new point
A further point, which is often forgotten, SQLConnection will only work with Microsoft SQL Server. If your SQL is provided by a different manufacturer the use OleDBConnection instead.