Pass List from Form3 to Form1

Question

I have 3 forms: form1(which I want to use my List from form3 in which I create List and Add things to it), form2 ( which contains a button to go back to form1 and a button to go to form3 and get values to the list.

I tried creating the following class:

public class ListArticle
    {
        public List<string> Clothes { get; private set; }
        public List<string> Colors { get; private set; }

        public ListArticle()
        {
            Clothes = new List<string>();
            Colors = new List<string>();
        }
    }

and then declare trying Adding things in the List from form3 like this:

// This is the Declaration

public ListArticle _articles = new ListArticle();

    public ListArticle Articles
    {
        get
        {
            return _articles;
        }
        set
        {
            _articles = value;
        }
    }

This is how I add:

_articles.Clothes.Add("T-shirt " + tshirt_number.ToString());
_articles.Colors.Add(closestColor2(clist, color));

and this is how I am trying to get the values:

when I close form3

I do this:

Form2 frm = new Form2();
frm.Show();
Articles = _articles;
this.Hide();

in form2 I do nothing..

and in form1 I tried to do it like this:

//declaration

public ListArticle Articles;

public ListArticle _articles
{
   get
   {
     return Articles;
   }
   set
   {
     Articles = value;
   }
}

//and this is how I tried to do it but it returns null everytime.

private void button3_Click(object sender, EventArgs e)
    {
        try
        {
            Form3 f = new Form3();

            f.Articles = Articles;

            foreach (string c in Articles.Clothes)
            {
                MessageBox.Show(c);
            }
        }
        catch 
        {
            MessageBox.Show("Articles is null.");
        }

    }

[Interaction between forms — How to change a control of a form from another form?](https://stackoverflow.com/questions/38768737/interaction-between-forms-how-to-change-a-control-of-a-form-from-another-form) — Reza Aghaei, Dec 28 '16 at 21:11
You asked a similar question yesterday which is still open. You need to learn more about how to communicate between forms, so spend some time to read the linked post. — Reza Aghaei, Dec 28 '16 at 21:13
@RezaAghaei I know but i felt like I gave too less information about what I really wanted to ask and to remake a full question with answers is bad. — C. Cristi, Dec 28 '16 at 21:14
@RezaAghaei also .. I tried to study this all day but couldn't figure it out and now I am just sad — C. Cristi, Dec 28 '16 at 21:15
`Form3 f = new Form3(); f.Articles = Articles;` → 1) You created a new instance of `Form3` 2) You assigned `Articles` of `Form1` to `Articles` of `Form3`. 3) In `Form1` you didn't instantiate `Articles` so Obviously its null. — Reza Aghaei, Dec 28 '16 at 21:23
@RezaAghaei for me looks like the opposite I assigned the `Articles` of `Form3` to `Articles` of `Form1`... — C. Cristi, Dec 28 '16 at 21:30
When you say `x=y` which one gets the value and will change? `x` or `y`? `f.Articles = Articles;` is equivalent to `f.Articles = this.Articles;` which means you are assigning `Articles` of current form to `Articles` of `f` which is a new instance of `Form3`. — Reza Aghaei, Dec 28 '16 at 21:31

score 0 · Answer 1 · answered Dec 28 '16 at 22:08

If you want to be able to share the articles between all forms you could make the Clothes and Colors collection static:

public class ListArticle
{
    public static List<string> Clothes { get; private set; }
    public static List<string> Colors { get; private set; }

    static ListArticle()
    {
        Clothes = new List<string>();
        Colors = new List<string>();
    }
}

You can then add articles form one form like this:

ListArticle.Clothes.Add("T-shirt " + tshirt_number.ToString());
ListArticle.Colors.Add(closestColor2(clist, color));

...and retrieve articles from another form like this:

private void button3_Click(object sender, EventArgs e)
{
    try
    {
        foreach (string c in ListArticle.Clothes)
        {
            MessageBox.Show(c);
        }
    }
    catch
    {
        MessageBox.Show("Articles is null.");
    }
}

Using this approach you don't have to create any additional "article" properties in either of the forms. You just access the same static collections from all forms.

Pass List from Form3 to Form1

1 Answers1