CODEWITHSUNDEEP
c#asp.netlist
eqinna
eqinna

Reputation: 331

Add new item to list without overwriting old item

I'm new to C#, but when I'm submitting a form, I catch the form values and create a new item of it and put it in a list according to the code below:

    public ActionResult Movie()
    {

        int id = Convert.ToInt16(Request.Form["inputmovieid"]);
        string name = Request.Form["inputmovietitle"];
        int year = Convert.ToInt16(Request.Form["inputproductionyear"]);

        List<Movie> movies = new List<Movie>();            

        Movie movieitem = new Movie(id, name, year);

        movies.Add(movieitem);

        return View(movies);
   }

In a .cshtml-file I then print the created item with a foreach loop, but the problem is that if I submit this form again with new values for a new item, it overwrites the old one in the list.

DESIRED RESULT: When submitting the form again I want a new item to be added to the list without overwriting the old one. Does anyone know how the code above can be modified to solve this?

Upvotes: 0

Views: 2207

Answers (1)

Jeroen van Langen
Jeroen van Langen

Reputation: 22038

You need to store the data into a database of keep track or a list inside a ViewState.

Something like:

public ActionResult Movie()
{
    var list = ViewState["MyList"] as List<Movie>;
    if(list == null)
    {
       list = new List<Movie>();
       ViewState["MyList"] = list;
    }
    int id = Convert.ToInt16(Request.Form["inputmovieid"]);
    string name = Request.Form["inputmovietitle"];
    int year = Convert.ToInt16(Request.Form["inputproductionyear"]);



    Movie movieitem = new Movie(id, name, year);

    list.Add(movieitem);

    return View(list);
}

But my knowledge of asp.net has faded a little, you might need to mark the Movie class as serializable,

[Serializable]
public class Movie
{
    ...
}

Every time you get a postback/reload, the whole class is reconstructed, so a storing a list into a field won't help you. That's why they invented the viewstate. (hidden formfield sent with the html)

Upvotes: 1

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