C# for MS SQL connection

Question

I am not an IT professional, and I would like to ask a question related to server connection.

Usually, I use ODBC connection string (such as below sample code), the only reason is: I can view(find out) server database property via Control Panel > Administrative Tools > ODBC Data Sources. Current code works fine for me.

Question: In general, which way of connection is better for MS SQL? Why? What are the difference?

If not using ODBC connection, what are substitutions for OdbcConnection/OdbcCommand/OdbcDataReader etc ?

Thanks.

OdbcConnection/OdbcCommand/OdbcDataReader 

OdbcConnection Cn = new OdbcConnection(GlobalVariables.ConnectionString);
            Cn.Open();
            string QueryM = "SELECT * From TableName";
            OdbcCommand cmdM = new OdbcCommand(QueryM, Cn);
            OdbcDataReader drM = cmdM.ExecuteReader();


OdbcDataAdapter AdapterTD = null;
        DataSet dSetTD = null;

Answer 1

You should use the classes in the SqlClient namespace. They are for connecting to Microsoft SqlServer

         SqlConnection Cn = new SqlConnection(GlobalVariables.ConnectionString);
         Cn.Open();
         string QueryM = "SELECT * From TableName";
         SqlCommand cmdM = new SqlCommand(QueryM, Cn);
         SqlDataReader drM = cmdM.ExecuteReader();