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Visual C# : cannot connect to local SQL database

I'm trying to connect to my local SQL express database with following code with no luck :
string strConnectionString = null;
SqlConnection cnn = null;
strConnectionString = "Data Source=" + txtSQLServer.Text.Trim() + ";Initial Catalog=" + txtSQLDatabase.Text.Trim() + ";User ID=user;Password=user";
cnn = new SqlConnection(strConnectionString);
MessageBox.Show(strConnectionString);
try
{
cnn.Open();
MessageBox.Show("Connection Open ! ");
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
The sql express database is running, because I can connect with it through SQL server management studio.
I already tried "localhost", "127.0.0.1", "PC-name/SQLEXPRESS"
error says : 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.
What more can I try?
edit : ok, found the problem
I needed to start the SQL server browser
connect to "PC-name/SQLEXPRESS"
But in the future I want to connect to an IP-address, how do I do this?
I tried this connection string :
strConnectionString = "Data Source=" + txtSQLServer.Text.Trim() + ",1433;Network Library=DBMSSOCN; Initial Catalog=" + txtSQLDatabase.Text.Trim() + ";User ID=user;Password=user";

azure connection string c#

I am trying to open connection with Azure SQL database. Tried creating usual connection = new MySqlConnection("Server=" + server + "Database=" + database + "Uid=" + uid + "Password=" + password); with every string variable ending with ; but yet it always fails to connect even if the data is correct. Tried to use given string for ADO.NET but then I am getting exception "keyword is not supported". I don't what else to actually.. Googled as much as possible but all solutions are quite the same and yet nothing works out for me :/

Firstly, azure databases don't use mysql. so using MySqlConnection() won't work.
instead use
SqlConnection connection = new SqlConnection(connectionstring);
Standard connection strings should be in the format
Server=tcp:[serverName].database.windows.net;Database=myDataBase;
User ID=[LoginForDb]#[serverName];Password=myPassword;Trusted_Connection=False;
Encrypt=True;
See https://www.connectionstrings.com/azure-sql-database/ for more options

var connectionString = #"Server=tcp:<dbname>.database.windows.net,1433;Initial Catalog=<databasename>;Persist Security Info=False;User ID=<userid>;Password=<password>;MultipleActiveResultSets=False;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;";
That's how I connect to my Azure SQL Database, works for me.

For MySQL In App you can use the fellowing code in c# to get the connection string:
static string getConnectionString()
{
#if DEBUG
string connectionString = "dbname=localdb;host=localhost:3306;user=root;pass=password;";
#else
string connectionString = Environment.GetEnvironmentVariable("MYSQLCONNSTR_localdb");
#endif
string[] options = connectionString.Split(";");
string database = options[0].Split("=")[1]; ;
string serverport = options[1].Split("=")[1];
string server = serverport.Split(":")[0];
string port = serverport.Split(":")[1];
string user = options[2].Split("=")[1];
string password = options[3].Split("=")[1]; ;
connectionString = $"server={server};port={port};database={database};user={user};password={password};";
return connectionString;
}

The standard .Net Framework provider format is:
Server=[serverName].database.windows.net;Database=myDataBase;
User ID=[LoginForDb]#[serverName];Password=myPassword;Trusted_Connection=False;
Encrypt=True;
Azure SQL Database is an SQL Server type database, not MySQL!

Have you followed Microsoft instructions?
https://learn.microsoft.com/en-us/azure/sql-database/sql-database-connect-query-dotnet-visual-studio
You have to create server-level firewall rule on azure too, to be able to connect.

Method fires an exception when trying to connect to remote SQL Server

I want to create a simple tool that connect to SQL Server then list all databases, and after user selects one of those databases, the tool will perform some SQL scripts on it.
Below is a method that should return a DataTable contains all my databases;
I send to it sqlServerIp as first parameter like 10.10.20.30 ip address not server name.
Also I didn't specify a SQL Server instance.
private DataTable GetSqlServerDatabases(String sqlServer, bool isWindowsAuth, String login, String password)
{
String connectionString;
DataTable databases;
if (isWindowsAuth)
{
connectionString = "Data Source=" + sqlServer + ",1433;Network Library=DBMSSOCN; Integrated Security=True;";
}
else
{
connectionString = "Data Source=" + sqlServer + ",1433;Network Library=DBMSSOCN;" + "User id=" + login + ";Password=" + password + ";";
}
try
{
using (var con = new SqlConnection(connectionString))
{
con.Open();
databases = con.GetSchema("Databases");
foreach (DataRow database in databases.Rows)
{
String databaseName = database.Field<String>("database_name");
short dbID = database.Field<short>("dbid");
DateTime creationDate = database.Field<DateTime>("create_date");
}
}
}
catch(Exception ex)
{
databases = null;
MessageBox.Show(ex.Message.ToString());
}
return databases;
}
When I try to call the method on more than one server I faced an exception:
Login failed. The login is from an untrusted domain and cannot be used with Windows authentication.
or
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 used connection string with Network Library=DBMSSOCN; after searching here on SO and web so I don't know what is the wrong with this method.

Remove Integrated Security parameter. This parameter is for trusted connections.
More samples on http://www.connectionstrings.com/sql-server

SQL query running as local user instead of user in connection string

I have a WPF application that accesses a SQL server using SqlConnection with a connection string.
private string connString =
"user id=*****;" +
"password=*****;" +
"server=1.1.1.1;" +
"Trusted_Connection = yes;" +
"database=****;" +
"connection timeout = 30";
private SqlConnection myConnection = new SqlConnection(connString);
The string contains the username and password for the account I want the program to use to access the database. This works as I would expect it to on my machine. Once I run it on another machine I get a an error:
"Login failed for user 'Domain\local user'"
I am sure that I am just missing some sort of setting or configuration.
Any help would be great

Trusted_Connection = yes tells SQL Server to use Integrated (Windows) Authentication. Your user name and password are ignored.

connect mysql database in websever with c# application

i have a PHP website and MySQL database in same web sever. i wont to connect that MySQL database with c# application. my c# application in run another computer.
how can i connect that MySQL database ?

First make sure you have downloaded and installed the MySQL Connector/NET from the MySQL official website. In this article, I will use the Connector/NET version 6.1.
Then add MySql.Data namespace in Reference
Then you can use mysql in .net
now create a connection strin like this
class ConnectToMySql{
private MySqlConnection connection;
private void Initialize()
{
server = "localhost";
database = "connectcsharptomysql";
uid = "username";
password = "password";
string connectionString;
connectionString = "SERVER=" + server + ";" + "DATABASE=" +
database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";
connection = new MySqlConnection(connectionString);
connection.Open();
}
}
Then
1 Create a MySQL command.
2 Assign a connection and a query to the command. This can be done using the constructor
3 using the Connection and the CommandText methods in the MySqlCommand class.
4 Create a MySqlDataReader object to read the selected records/data.
5 Execute the command.
6 Read the records and display them or store them in a list.
7 Close the data reader.
8 Close the connection.
I tooth this will help full for you . now you can start working on mysql in .NET
Best of luck

you firstly have to add mysql ref to your project:
plz right click on your project and go to the ref part in it
after that try to find mysl.conncetor and tick it
and refresh your project and firstly try to add using mysql.net.client
now you can use data base located in the mysql db from c# coding
be sure you have downloaded both mysql connector and installaton which is about 500 mb files.
class ConnectToMySql{
private MySqlConnection mscon;
private void Initialize()
{
server = "localhost";
database = "your own database name";
uid = " your username";
password = "your password";
string const;
connectionString = "SERVER=" + server + ";" + "DATABASE=" +
database + ";" + "UID=" + uid + ";" + "PASSWORD=" + password + ";";
mscon= new MySqlConnection(const);
mscon.Open();
}
}