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I know the error - Adding to list only takes the last item

Posted on 2014-11-22
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Last Modified: 2016-02-17
I know what's causing this. I have "new" so with each loop, I create a new list. But don't know how to fix this.

var model = new MyViewModel();
            DataClasses1DataContext db = new DataClasses1DataContext();

            var p = from c in db.states
                select c;

            var ddllist = new List<OptionItem<string>>();

            foreach (var row in p)
            {
                model.testcountries = new List<OptionItem<string>>()
                {
                    new OptionItem<string>() {DisplayMember =row.Name, CountryCode = row.country, Value = row.Id.ToString()},
                };
            }

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This works but it's hard coded:
   model.testcountries = new List<OptionItem<string>>()
        {
           new OptionItem<string>() { DisplayMember = "MO", CountryCode = "US", Value = "1" },
            new OptionItem<string>() { DisplayMember = "PO", CountryCode = "US", Value = "2" },
            new OptionItem<string>() { DisplayMember = "LO", CountryCode = "CA", Value = "3" }
        };

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0
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Question by:Camillia
2 Comments
 
LVL 35

Accepted Solution

by:
Robert Schutt earned 500 total points
ID: 40460378
Well normally I would say you should just create the list before the loop and add a new item for every row but in this case you should be able to replace the whole code (lines 4-15) with:
model.testcountries = (from row in db.states select new OptionItem<string>() { DisplayMember = row.Name, CountryCode = row.country, Value = row.Id.ToString() }).ToList();

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I can't really test this, only with some fake classes I created to match your code (I think).

So just for completeness when the above LINQ is not an option you would do something like this (which is basically just a slight reshuffle of your posted code):
            var p = from c in db.states
                    select c;

            var ddllist = new List<OptionItem<string>>();

            foreach (var row in p) {
                ddllist.Add(
                    new OptionItem<string>() {DisplayMember =row.Name, CountryCode = row.country, Value = row.Id.ToString()}
                );
            }

            model.testcountries = ddllist;

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0
 
LVL 7

Author Comment

by:Camillia
ID: 40460523
thanks, let me try it. I spent a lot of time on this. It's ok if it's not done in LINQ. I just need to get it done as I have a demo.
I'll post back.
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