Question

i have two lists:

List<comparerobj> list_c = new List<comparerobj>();
List<comparerobj> list_b = new List<comparerobj>();

i’m filling lists somehow

then i’m trying to find elements in list_b which list_c doesnt contain:

foreach (comparerobj b in list_b)
{
    bool lc = !list_c.Contains(b);
    if (lc != true)
    {
        data.Add(b);
    }
}

but for any b i’m getting that lc = true. what am i doing wrong?

Answer 1

How your objects are compared? By default .NET framework compares objects by references. For Example if you create following class:

class A
{
    string Name { get; set; }
}

and follwing code

A a1 = new A() { Name = "a" };
A a2 = new A() { Name = "a" };

then you will find that these objects are different.

You need to override Equals method for .NET Framework to treat above objects as equal.