C# Linq - Join 2 Lists, add in extra properties to existing List -

suppose have following 2 classes set in c# program:

public class class1 {     public string var1;     public string var2;     public string var3;      public string var4;     public string var5; }  public class class2 {     public string var1;     public string var2;     public string var3;      public string var6;     public string var7; } 

---

and have following code in method:

public void mymethod() {     list<class1> class1data = getclass1data();     list<class2> class2data = getclass2data();      var joineddata = (from c1 in class1data                         join c2 in class2data                         on new                         {                             c1.var1,                             c1.var2,                             c1.var3                         }                         equals new                         {                             c2.var1,                             c2.var2,                             c2.var3                         }                         select new                         {                             c1.var1,                             c1.var2,                             c1.var3,                             c1.var4,                             c1.var5,                             c2.var6,                             c2.var7                         }).tolist(); } 

now, i'd like, but, ideally, i'd extend class1 have 2 fields - var6 , var7 , have results class2 added onto class1data list rather create new object joined data (trying conserve memory rather have 2 separate lists).

i'm sure has been asked , answered many times before, can't seem find best way this.

thanks!!