C# and SQL data connection

What you "need" is the ability to Google.

The .Net framework has comprised on ADO.Net[^] since version 1.1.
ADO.Net provides all the classes you need to connect with a variety of different database types including SQL. (Which uses the System.Data.SQLClient namespace).

I suggest you have a read on that and also on the FAQ on this forum for how to post questions as it will provide you with guidance on how you aught to approach posting questions here in order to get the best response.

The sql connection get easy way u didnot reconfigure your just hardcoded the

following for windows authentication

string connection=datasource="servername" intial catalog="databasename" integrated security="true"

sql server authetication like

string connectiondatasource="servername" intial catalog="databasename" Persistinfo security="true" userid="sa"password="123"

to reconfigure the connection string just use txt file or xml
i example to things
place the debug folder dbpathi.ini file (crete new txt file save with extension .ini file )

datasource="servername" intial catalog="databasename" integrated security="true" <pre lang="SQL">

enter following connection strings

to the simple code

filestream fs=new file stream();
fs=file.open(appdomain.currentdomain.basedirectory+"Dbpath.ini");

streamreader sa=new stream reader(fs);
string reader=sa.readtoend()

sqlconnection connnctoin=new sqlconection(reader);
conection.open()

=

you need a SqlConnection class for connectivity Sql server like that

static SqlConnection _con = new SqlConnection("Connection String");

and another need a Sqlcommand for pass a Query front to Back end Server.

SqlCommand _cmd;
 _cmd = new SqlCommand("SELECT *  FROM Table_Name WHERE ColoumnName like '%" + name + "%'", _con);
            _con.Open();
            _rd = _cmd.ExecuteReader();
            dt1 = new DataTable();
 dt1.Load(_rd);
_con.Close();

For any query left the comment.