pass value to query

Question

How to pass value of string to a query?

Following is the code - 

public string _advis

        {

            set { string ad1 = value; }

        }

MySqlCommand com1 = new MySqlCommand("Select ID from swapnali.login where Advisor_Name='"_advis "'", conn); 

How to pass value of _advis to mysql query. Here I have passed _advis, but it is giving error.

Thanks