To connect to MS SQL Server use the following connection string...

 SqlConnection _connection = new SqlConnection("data source=localhost;initial catalog=blog;integrated security=SSPI;persist security info=False;Trusted_Connection=Yes");

 When using ASP.Net application you may get an error of SqlDataReader or SqlCommand that 

 e.g. There is already an open DataReader associated with this Command which must be closed first

 In this case use the following connection string to avoid such errors...

 SqlConnection _connection = new SqlConnection("MultipleActiveResultSets=True;data source=.;initial catalog=blog;integrated security=SSPI;persist security info=False;Trusted_Connection=Yes");