Inheritance with C#

Question

I am trying to use inheritance to pass a string from one form to another using a ref.class. Im looking at it and to be honest I think this should work. But when debugging nothing comes up in my settings textBox...

Here is my reference Class:

    class Ref
{

    private String _url;

    public String Sett
    {

        set { _url = value; }
    }
    public String Gett
    {
        get { return _url; }
    }

and I am setting it from the main form and getting it from a settings form

Here is my main Form:

    private void webBrowser1_DocumentCompleted(object sender,WebBrowserDocumentCompletedEventArgs e)
        {Ref reff = new Ref();
        this.Text = webBrowser1.Document.Title + " - NHS Cerner Booking Dash";
        textBox1.Text = webBrowser1.Document.Url.ToString();
        reff.Sett = webBrowser1.Document.Url.ToString();

and finally this is my Settings form

    public void load()
    {
        Ref reff = new Ref();
        textBox3.Text = reff.Gett;
    }

Im sure this looks a bit complicated. So to clarify I want to take the URL from the main form and set it to my ref.class and then get it from the Ref.class to set it to a textBox in my Settings form. Thank you for looking.

Why have you got two properties, one with a getter and one with a setter, rather than a single "Value" property with both a getter and a setter? Not that that would fix the problem... — Jon Skeet, Feb 07 '12 at 14:17

score 5 · Answer 1 · answered Feb 07 '12 at 14:19

To start with, this has nothing to do with inheritance.

No, it definitely shouldn't work. You're creating two separate instances of Ref - so setting the value in one of them won't make it available in the other. You would need to create one instance of Ref and make both forms aware of it - so that they can use it as a shared communication channel.

Personally I don't think that's the best way of communicating between the forms anyway - you should consider using events, for example - but that's why it's not working at the moment.

As noted in a comment, it's very strange to have two separate properties. If I really wanted this behaviour, I would have written that class as:

public class MutableWrapper<T>
{
    public T Value { get; set; }
}

score 3 · Answer 2 · edited May 23 '17 at 11:48

3

Because you create new object when write "new"

public void load()
{
    Ref reff = new Ref();
    textBox3.Text = reff.Gett;
}

İf you debug you can see reff is empty..

this should help you

edited May 23 '17 at 11:48

Community

1
1

answered Feb 07 '12 at 14:20

Farid Movsumov

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score 2 · Answer 3 · answered Feb 07 '12 at 14:20

2

You are creating a new Ref object in each place so the value you set in webBrowser1_DocumentCompleted is on a different object to that retrieved in load.

answered Feb 07 '12 at 14:20

ChrisF

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score 1 · Answer 4 · answered Feb 07 '12 at 14:20

1

Why don't you just create a public property in the form that will be opened. This way you can set it just before you open it and use it further on.

answered Feb 07 '12 at 14:20

Abbas

14,186
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score 1 · Answer 5 · answered Feb 07 '12 at 14:21

Puh, there to start.

At first i suggest you simplyfy your class.

public class Ref
{
    public string Url { get; set; }
}

But this is not the problem.

The Problem is that you have two different instances of your Ref class.

So you can do two things.

If this is a setting form, you should save the value of Ref.Url to Application Settings. OR
You must pass the instance of Ref to your Settings form.

score 0 · Accepted Answer · answered Feb 07 '12 at 14:19

0

You don't need any Ref class for this. In your second form create a public property and while creating that form access this property and assign the value of URL.

Click here to see a post which does similar thing.

In Form2

 public string URL {get; set;}

In Form1

 Form2 theNewForm = new Form2();
 theNewForm.URL = "your url value";
 theNewForm.Show();

Hope this works for you.

answered Feb 07 '12 at 14:19

Amar Palsapure

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This solution turned out to be the simplist. Thank you very much. – Marshal Feb 07 '12 at 14:56

score 0 · Answer 7 · answered Feb 07 '12 at 14:21

0

Ok, this is ugly, do this instead:

class Ref
{

    private String _url;

    public String URL
    {

        set { _url = value; }
        get { return _url; }
    }
}

Then you need to create a Ref instance inside your main class and pass it to your Settings class when you create it. Then you can fill it up inside your Settings class like so:

myref.URL = "whatevergoeshere";

When your Settings dialog is finished, you'll be able to look inside your Ref object and see what the URL is.

answered Feb 07 '12 at 14:21

Tony The Lion

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The annoying thing is I did this was Java in the past and it was really simple at the time. Was clean and now doing it with C# completely forgot everything. Thank you for your help as I will use this as a reference in the future when using a few objects. – Marshal Feb 07 '12 at 14:58

score 0 · Answer 8 · answered Feb 07 '12 at 14:25

Okay you're really not using inheritance... and the issue you're having is the Ref's that you're declaring in two different places are not the same.

        private void webBrowser1_DocumentCompleted(object sender,WebBrowserDocumentCompletedEventArgs e)
        {
            Ref reff = new Ref();
            //not the same "Ref" as below
        }

        public void load()
        {
            Ref reff = new Ref();
            //not the same "Ref" as above
        }


        //consider using properties instead of members... you get the get/set for free
        public class Ref
        {
            public string URL { get; set; }
            public void Load()
            {
                //do your load set
                this.URL = "What you want";
            }
            //...
        }

        //you can also declare the constructor on the fly if you want.. or call the Load() method
        Ref myRef = new Ref()
        {
            URL = "What you want"
        };

Inheritance with C#

8 Answers8