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connection string from c# to msql

I am new to msql and i am working on MySQL Workbench 8.0 CE
I am trying to bind data from database to datagridview as show below but i am getting error below
but I am able to connecto my database using MySQL Workbench 8.0 CE so the connection to up so what I can do ?
public void GetPersonData()
{
string connstr = "Server=localhost;Database=newsequesterdb;Uid=reser;Pwd=00";
string query = "SELECT * FROM NEWSEQUESTERDB.PERSON;";
using (SqlConnection conn = new SqlConnection(connstr))
{
using (SqlDataAdapter adapter = new SqlDataAdapter(query, conn))
{
DataSet ds = new DataSet();
adapter.Fill(ds);
dgv_data.DataSource = ds.Tables[0];
}
}
}
error message
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)

SqlConnection is specific to MS SQL Server. Use MySqlConnection (and associated command and data adapter classes) instead.
Note that MySqlConnection is not built in to the .NET Framework - you'll need to install it separately.

The thing is that you cannot use an SqlConnection instance nor SqlAdapter, those are intended to be SQL Server connection classes. And this you can see by the exception itself.
...(provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
So, what's next? You should really look up to this question and may solve a few doubts.
From that question we can see that is using other references to connect to MySQL. Specifically Oracle's nugget package: MySQL.Data
using MySql.Data;
using MySql.Data.MySqlClient;
From that question example:
var dbCon = DBConnection.Instance();
dbCon.DatabaseName = "YourDatabase";
if (dbCon.IsConnect())
{
//suppose col0 and col1 are defined as VARCHAR in the DB
string query = "SELECT col0,col1 FROM YourTable";
var cmd = new MySqlCommand(query, dbCon.Connection);
var reader = cmd.ExecuteReader();
while(reader.Read())
{
string someStringFromColumnZero = reader.GetString(0);
string someStringFromColumnOne = reader.GetString(1);
Console.WriteLine(someStringFromColumnZero + "," + someStringFromColumnOne);
}
dbCon.Close();
}

Connect to SQL Server 2008 Express database using C#

I am developing a Winforms application in which I am using SQL Server 2008 Express Edition as backend. But I am getting error:
Additional information: An attempt to attach an auto-named database for file D:\Hardik\Hardik\dotnet\TestApplication\TestApplication\bin\Debug\MyDatabase.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share.
My code is:
private void Form1_Load(object sender, EventArgs e)
{
SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["MyConnection"].ConnectionString);
SqlCommand cmd = new SqlCommand();
cmd.Connection = con;
cmd.CommandText = "Select * From MyTable";
cmd.CommandType = CommandType.Text;
da = new SqlDataAdapter();
da.SelectCommand = cmd;
dt = new DataTable();
ds = new DataSet();
da.Fill(ds, "Login");
dt = ds.Tables[0];
dataGridView1.DataSource = dt;
}
and my app.config file is:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<add name="MyConnection"
connectionString="Server=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|\MyDatabase.mdf;Integrated Security=True; User Instance=True"
providerName="System.Data.Client"/>
</connectionStrings>
</configuration>
Where I am wrong?

use double slash instend of single slash.
A UNC path uses double slashes or backslashes to precede the name of the computer.
<connectionStrings>
<add name="MyConnection" connectionString="Server=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\MyDatabase.mdf;Integrated Security=True; User Instance=True" providerName="System.Data.Client"/>
</connectionStrings>
for instance failure
As you got the error "instance failure", that might be the error with your SQL Server instance..
Make sure your SQL Server instance(MSSQLSERVER) is running, where you can check in: Services list. TO get into services list: open run dialog box and type: "services.msc" (without quotes) and hit Enter. That takes you to services management console, where you can check whether your instance in running or not..
If the problem still persists, then try using: Data Source=.\SQLEXPRESS instead.. :)

c# localdb v11 not saving to file

I want to create a program for my school, handling marks and certificates.
To save the data I have to use a "local" network shared database-file, because we are using Citrix and there is no possibility to setup an seperate SQL-Server.
I tried it with localdb v11 with the following code:
string connectionString = #"Data Source=(LocalDB)\v11.0; AttachDbFilename=D:\_prog\TestNoten\TestNoten\bin\Debug\Database1.mdf; Integrated Security=True;Connect Timeout=3;";
SqlConnection connection = new SqlConnection(connectionString);
string sql = "INSERT INTO test(name) VALUES('lal')";
SqlCommand cmd = new SqlCommand(sql, connection);
connection.Open();
cmd.ExecuteNonQuery();
connection.Close();
DataTable table = new DataTable();
SqlDataAdapter adp = new SqlDataAdapter("Select * from test", connection);
connection.Open();
adp.Fill(table);
MessageBox.Show(table.Rows[0][1].ToString());
The MessageBox says "lal", but when I restart the program with "lala" instead of "lal", it will show "lala" and not the expected "lal".
So when closing the program, the database won't be saved correctly. I also opened the file over VSs Data Connections, and the testing table is empty.
Is there something I missed?

Error While Adding DataSource in Data Connections

When I tried to add a connection it is showing the following error as shown in the attachment. “Unable to open the physical file. Access is Denied” .
When I searched about it, it suggest for adding the SQL Server’s account to the folder. Then, using the following query I found that the account is “LocalSystem”. When I tried to add “LocalSystem” to ACL of the folder, such an account is not available. How do we resolve it and add the connection to DBML?
Note: When I used DataReader with the database name in a C# program, it worked well.
Query Used:
declare #sqlser varchar(20)
EXEC master..xp_regread #rootkey='HKEY_LOCAL_MACHINE',
#key='SYSTEM\CurrentControlSet\Services\MSSQLSERVER',
#value_name='objectname', #value=#sqlser OUTPUT
SELECT convert(varchar(30),#sqlser)
Working C# Program:
SqlDataReader rdr = null;
SqlConnection con = null;
SqlCommand cmd = null;
try
{
// Open connection to the database
string ConnectionString = "server=D088DTRV;integrated security=true; database=BankAccount";
con = new SqlConnection(ConnectionString);
con.Open();
string CommandText = "SELECT * FROM Account";
cmd = new SqlCommand(CommandText);
cmd.Connection = con;
rdr = cmd.ExecuteReader();
while (rdr.Read())
{
string test = rdr["AccountType"].ToString();
}
}

The problem was related to Data Connections.
In the advanced window, when I checked, it was trying for ./SQLExpress. I modified it with ".".
I restarted the machine. I also stopped the SQLExpress in the services.msc
Data Source=.;AttachDbFilename=C:\DevTEST\Databases\LibraryReservationSystem.mdf;Integrated Security=True;Connect Timeout=30;User Instance=True

Problems connecting to .sdf database through SqlConnection/SqlCeConnection

I'm having immense trouble getting a connection to a .sdf (sql compact edition) database. I can connect initially to extract rows in order to verify a username/password, but when I try to add items to the database, either by a SqlCeConnection/SqlCeCommand command or by trying to add items SqlClient/SqlCommand connection, I have no luck. I get:
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)
when using:
private void button1_Click_1(object sender, EventArgs e)
{
System.Data.SqlClient.SqlConnection sqlConnection1 =
new System.Data.SqlClient.SqlConnection("Data Source=C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf");
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
cmd.Connection = sqlConnection1;
sqlConnection1.Open();
cmd.ExecuteNonQuery();
sqlConnection1.Close();
}
or when I try:
System.Data.SqlClient.SqlConnection sqlConnection1 =
new System.Data.SqlClient.SqlConnection("Data Source=C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf");
System.Data.SqlClient.SqlCommand cmd = new System.Data.SqlClient.SqlCommand();
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
cmd.Connection = sqlConnection1;
sqlConnection1.Open();
cmd.ExecuteNonQuery();
sqlConnection1.Close();
Nothing happens, it seems to work until I check the .sdf file and see nothing has been added. I do not have SQL Server CE installed, though I do have 2008 R2 installed (I'm working on someone else's project).
Right now I'm not worried about the security holes, I'm just trying to successfully add a record. Any help would be much appreciated, as I've spent about three or four hours working on something I figure would take about 20 minutes.

Probably you have found the solution by now, but if you use a sdf file, the assembly you should add a reference to System.Data.SqlServerCe and then something like:
SqlCeConnection sqlConnection1= new SqlCeConnection();
sqlConnection1.ConnectionString = "Data Source = C:\\Users\\Tim\\Documents\\Visual Studio 2010\\Projects\\Dispatch POS\\Dispatch POS\\GhsDB.sdf";
System.Data.SqlServerCe.SqlCeCommand cmd = System.Data.SqlServerCe.SqlCeCommand;
cmd.CommandType = System.Data.CommandType.Text;
cmd.CommandText = "INSERT [Employee Table] (SSN, FirstName) VALUES ('555-23-4322', 'Tim')";
cmd.Connection = sqlConnection1;
sqlConnection1.Open();
cmd.ExecuteNonQuery();
sqlConnection1.Close();

you most to use sqlceconnection and sqlcecommand classes. like this :
SqlCeConnection conn = new SqlCeConnection(connectionString);
SqlCeCommand cmd = conn.CreateCommand();
conn.Open();