Compare objects of Same class and store value in a List of another class

class Program
{
 static void Main()
 {
   SomeCustomClass a = new SomeCustomClass();
   SomeCustomClass b = new SomeCustomClass();
   a.CwNumber = "A";
   a.MaterialId = 1;
   a.MaterialName = "Material1";
   a.ListMyClass.Add( new MyClass1 { id = 11,Name="Name1" });
   a.ListMyClass.Add(new MyClass1 { id = 12, Name = "Name2" });

   b.CwNumber = "A";
   b.MaterialId = 2;
   b.MaterialName = "Material2";
   b.ListMyClass.Add(new MyClass1 { id = 21, Name = "Name3" });
   b.ListMyClass.Add(new MyClass1 { id = 22, Name = "Name4" });

   List<Variance> rt = a.GetDiffValue(b);
 }

public List<Variance> GetDiffValue<T>(this T val1, T val2)
{
  List<Variance> variances = new List<Variance>();
  Variance v = new Variance();
  PropertyInfo[] pi = val1.GetType().GetProperties();
  foreach (PropertyInfo p in pi)
   {
       Variance v1 = new Variance();
       if (p.PropertyType.IsGenericType == true)
       {
           v1.Prop = p.Name;
           v1.valA = p.GetValue(val1, null);
           v1.valB = p.GetValue(val2, null);
       }
       else
       {
           v1.Prop = p.Name;
           v1.valA = p.GetValue(val1,null);
           v1.valB = p.GetValue(val2,null);
       }
       if (!v1.valA.Equals(v1.valB))
       {
           variances.Add(v);
       }
   }
   return variances;
 }
}

public class SomeCustomClass
{
   public int MaterialId { get; set; }
   public string CwNumber { get; set; }
   public List<MyClass1> ListMyClass { get; set; }
   public UsesModel Uses { get; set; }

   public SomeCustomClass()
   {
       ListMyClass = new List<MyClass1>();
   }
}
public class MyClass1
{
   public int id;
   string Name;
}

public class Variance
{
    public string propertyName { get; set; }
    public object OldValue { get; set; }
    public object NewValue { get; set; }
}