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How to connect to a SQL Server instance with C# using Visual Studio

I am unable to connect to SQL Servers that have the '\' char which is used when connecting to a server instance. Any other type of server works without any issues. Any support or resource on this issue would be extremely helpful as I have exhausted my possible solutions.
Thanks!
Chris
I have tried:
- adding/removing the '#'
- using a double '\'
- hard coding the server name and connecting
var masterConnString = $#"Server={Server}; Database={ProjectCode}; Trusted_Connection=True;";
using (var connection = new SqlConnection(masterConnString))
{
connection.Open();
//do something
connection.Close();
}
The following error occurs:
System.Data.SqlClient.SqlException HResult=0x80131904 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)
Source=.Net SqlClient Data Provider
Update:
When attempting to update the SQL Server Configuration Manager the connection fails due to lack of permissions.

Remove the trusted param and add this param
"Integrated Security=SSPI"
This always works with me when the server don't have any authentication

Connection string to SQL Server Express only works from the same server but not from other clients

I have this connection string and working well when I test my aplication from the same SQL Express, I have an instance called DOKUSTAR.
using (SqlConnection conn = new SqlConnection(#"server=.\DOKUSTAR;Database=RdaDB10;Trusted_Connection=Yes"))
using (SqlCommand comm = new SqlCommand(#"select top(1) pais, clase, operation from Document_Class where codigoafip = #codafip", conn))
The problem is when I tried to connect from outside of the server does not works the connection and show me the following messages:
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).
Any suggestions will be greatly appreciated.

.\DOKUSTAR refers to an instance of DOKUSTAR on the current machine.
You need to change it to MACHINE_NAME\DOKUSTAR

A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible.

I am running a local mysql database on my computer using wampserver. I have made a c# console application that I want to use to update values in a table. However I am having issues connecting to the database. My password is an empty string.
string user = "John Doe";
string queryString = "UPDATE users SET is_awesome=1 WHERE user=#a1";
string connectionString = "Server=localhost;Database=mydatabase;User Id=root;Password=;";
SqlConnection connection = new SqlConnection(connectionString);
connection.Open();
SqlCommand cmd = new SqlCommand(queryString, connection);
cmd.Parameters.Add("a1", user);
cmd.ExecuteNonQuery();
However when I attempt to run this code I get the following error:
System.Data.SqlClient.SqlException
System.Data.SqlClient.SqlException: '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)'
Inner Exception
Win32Exception: The system cannot find the file specified
I believe my database allows remote connections because I am able to connect to it using a different php application I am running. How can I connect to a sql database from c# and run my query?

You must connect to MySql witch is specific for MySql Like MySqlConnection for more look this tutorial
or this

SQL Server with C#

I am writing a program that connects to a SQL Server (IGOR-PC - SQL Server 10.50.4044 - instance Igor-PC\Igor)
The code is this:
SqlConnection myConnection = newSqlConnection("Server=.\\Igor;Database=Prueba");
myConnection.Open();
But I get this 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)
not monitored System.Data.SqlClient.SqlException
Thanks!

Try This
SqlConnection myConnection = new SqlConnection("Data Source=Igor;Initial Catalog=Prueba;Integrated Security=True");
Edit2:
For the Above Picture and for TEST_DB database the Connection String should be written as
SqlConnection myConnection = new SqlConnection("Data Source=AJMOT-PC;User ID=sa;Password=thisismypassword;Initial Catalog=TEST_DB;Integrated Security=True");
If you are using the Window authentication for sql server then you don't need to declare the User ID=sa;Password=thisismypassword section.

Connect to External SQL Database in C#

I've got an SQL server and database setup on an external server (let's call the domain name "hello.com" for the purposes of this), and I want to connect to this server via a C# program. So far I have this (All server/database details are different to the real ones):
private static void SetupSQL()
{
string connectionString = "server=hello.com; database=db1; uid=user1; pwd=xxxxx;";
connection = new SqlConnection();
connection.ConnectionString = connectionString;
try
{
connection.Open();
Console.WriteLine("Connected");
}
catch (Exception e)
{
Console.WriteLine(e.Message.ToString());
}
}
This is giving me an 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)
I have checked all the connection string, and I am allowed remote access, as I have SQLWorkbench open querying the database right now on the same computer.
Any ideas?

You'll need the MySQL driver:
http://dev.mysql.com/downloads/connector/net/
You can then use the the MySqlConnection connection class to connect.
MySqlConnection connection = new MySqlConnection(connectionString);
http://www.codeproject.com/Articles/43438/Connect-C-to-MySQL

You can't use SqlConnection object to connect to MySQL database, you should use MySqlConnection instead after you import its dll