C# Object Assignment

Question

I'm writing a code in C#. Please see below codes.

    //-- Constructor
    public frmInvoice(EditInvoice editInvoice)
    {
        InitializeComponent();

        originalInfo = new EditInvoice();
        editedInfo = new EditInvoice();

        originalInfo = editInvoice;
        editedInfo = editInvoice;
        payment = new Payment();
    }

    //-- Process
    private void btnOk_Click(object sender, EventArgs e)
    {
        editedInfo.AppliedAmount = Convert.ToDouble(txtAppliedAmount.Text);
        editedInfo.PaymentCode = cboPaymentCode.SelectedValue.ToString();
        editedInfo.Remarks = txtRemarks.Text;

        if (originalInfo.AppliedAmount != editedInfo.AppliedAmount ||
            originalInfo.PaymentCode != editedInfo.PaymentCode ||
            originalInfo.Remarks != editedInfo.Remarks)
        {
            editedInfo.IsEdited = true;
        }
    }

Now the question is, why the original object **originalInfo** also changed that is supposedly not. It's annoying!

Additional: Is there a better/shortest way to compare to object (models) if have difference?

You assign both `originalInfo` and `editInfo` to refer to the same object in the constructor. Obviously "changing one of them" will appear to change both, since they both refer to the same, single, object. — Lasse V. Karlsen, Sep 01 '14 at 06:39
@Lasse but i have it assigned on different variable. so how could i do this successully? — Bryan, Sep 01 '14 at 06:41
@Bryan - Think of the variable as a giant arrow showing you the way to its datas location in memory — Sayse, Sep 01 '14 at 06:42
http://stackoverflow.com/questions/2486297/object-assignment — George Vovos, Sep 01 '14 at 06:43
Add a new question for the additional question. There certainly are other ways. — Nick N., Sep 01 '14 at 13:16

Nick N. · Accepted Answer · 2014-09-08T09:10:16.387

1

Since editInvoice is probably a reference type, you should clone it instead of assigning it directly.

http://msdn.microsoft.com/en-us/library/system.object.memberwiseclone(v=vs.110).aspx

Update: since you state that editInvoice is a model, it is a reference type, any class is a reference type. A struct would be a value type for example. See this article for more information: http://msdn.microsoft.com/en-us/library/t63sy5hs.aspx

edited Sep 08 '14 at 09:10

answered Sep 01 '14 at 06:38

Nick N.

12,902
7
57
75

"No, it's not a reference type".. Although I'm skeptical, its hard to tell without seeing the implementation. – Sayse Sep 01 '14 at 06:39
editInvoice is a model. already successfully cloning it using MemberwiseClone. thanks! – Bryan Sep 01 '14 at 07:25
@Bryan nice to see that it works, I updated my answer, so you have some more information. – Nick N. Sep 01 '14 at 08:16

C# Object Assignment

1 Answers1