Re: Object equals

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"tshad" <tfs@xxxxxxxxxxxxxx> wrote in message news:#LN16aTYIHA.6140@xxxxxxxxxxxxxxxxxxxxxxx
I am looking at the object equals methods and am confused.

I was under the impression that o.equals compares content (not whether they are the same object as o1==o2 does).

But in my example, this doesn't seem to be happening.

If I have a class Account and I create 2 objects with this class exactly the same way - the content should be equal (I would think).

Here is the code I am running and all the results make sense to me except the a3.Equals(a4) which should be true.

**************************************
Account a3 = new Account(1000.0, "Count Dracula", 500);
Account a4 = new Account(1000.0, "Count Dracula", 500);

if (a3 == a4)
Console.WriteLine("a3 == a4");
else
Console.WriteLine("a3 != a4");

if (a3.Equals(a4))
Console.WriteLine("a3.Equals(a4)");
else
Console.WriteLine("a3.NotEquals(a4)");

Console.WriteLine("\na3 content:");
a3.Report();
Console.WriteLine("\na4 content:");
a4.Report();


a3 = a4;
if (a3 == a4)
Console.WriteLine("\nAfter a3=a4 a3==a4");
else
Console.WriteLine("\nAfter a3=a4 a3!=a4");
***************************************

The results:
******************************
a3 != a4
a3.NotEquals(a4) <--- Should be equal as the next set shows content the same

a3 content:
Account Name: Count Dracula
Balance: 1000
Overdraft Limit: 500
Penalty: 25

a4 content:
Account Name: Count Dracula
Balance: 1000
Overdraft Limit: 500
Penalty: 25

After a3=a4 a3==a4
********************************

Why is a3.Equals(a4) showing as not equal?

Thanks,

Tom

From the Object class Equals method docs:

<quote>
The default implementation of Equals supports reference equality only, but derived classes can override this method to support value equality.

For reference types, equality is defined as object equality; that is, whether the references refer to the same object. For value types, equality is defined as bitwise equality. The ValueType class supports value types.
</quote>
To get the behavior you seek, you must override the Equals() method in your class to do a field by field comparison.



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