asp.net mvc entity framework conditions

Such a question In C#, I used the{[4] class]}

 SQLiteConnection myConnection = new SQLiteConnection(Connect);
          myConnection.Open();

The query string was constructed from the selection conditions

 if (chk0.Checked) { param1 = " AND fire = 0 "; }
else if (chk1.Checked) { param1 = " AND fire = 1 "; }
else {param1 = " "}

 if (chk3.Checked) { param2 = " AND str = 0 "; }
else if (chk4.Checked) { param2 = " AND str = 1 "; }
else {param2 = " "}
Connect = "SELECT * FROM item WHERE " + param1 + param2 ;

As you can see, the query in particular WHERE is based on the results of if

Question? How to achieve the same result using entity framework

At the moment, I create a separate request in each if condition, which is very inconvenient because there are quite a lot of parameters.

        if (vulnerability != -100 && raite == "-100")
        {
            return from Name in northwind.name
                   where class_tip_list.Contains(Grp.class)  
                   select new { тут выборка };
        }
        else
        {
            return from Name in northwind.name
                   where Grp.level >= slider_min
                   select new { тут выборка };
        }