LINQ to XML binding to asp.Net DropDownList

Question

I'm trying to use LINQ and so I can bind it to an ASP.NET dropdown.

So far; this is what I have in terms of my LINQ expression; I'm new to LINQ, I started learning it this morning.

 county.DataSource = (from taxUnit in TaxUnits.Descendants("CodeData")
    join taxType in TaxTypes.Descendants("CodeData")
      on
      taxUnit.Attribute("taxuntype").Value
      equals
      taxType.Attribute("codeid").Value
    where taxType.Attribute("taxuntypky").Value == "CO"
    select new
    {
      County = taxUnit.Attribute("desc"),
      CodeID = taxUnit.Attribute("codeid")
    });

  county.DataTextField = "desc";
  county.DataValueField = "codeid";

  county.DataBind();

Originally I was trying to convert it into a datatable; I've been informed you can actually do direct LINQ to DropDownList binding.

          <asp:Label AssociatedControlID="county" runat="server">County</asp:Label>
          <asp:DropDownList
            ID="county"
            runat="server" />

So far the result is... when I look at the dropdown box. Based on what I'm getting from LINQPad I expect

County CodeID 
Willow County 1 
CP2 TU 2

The only problem with the current answer is I have no idea how it works, thus I do not understand how to convert it to what I want.

I was previously able to use an ObjectDataSource that pointed to this method, and made a mock for List just to play with databinding.

Do you know you can bind LINQ result directly without intermediate DataSet? — abatishchev, Jan 31 '14 at 22:12
...nope. when I get back to my computer I'll have to look that up. — , Jan 31 '14 at 22:13
LINQ resulting class should have the properties you bind against. And implement ILIst, i.e. call `ToArray()` or `ToList().` But I may be wrong in the last sentence. — abatishchev, Jan 31 '14 at 22:37

score 1 · Accepted Answer · answered Jan 31 '14 at 22:23

1

If the actual question is - how to bind LINQ to XML result onto a DropDownList then here's a code from my old ASP.NET project. I bind LINQ to Entities result onto GridView. For DropDownList should work same way:

public IEnumerable<IDraft> Get(int accountId, DateTime startDate, DateTime endDate)
{
    using (var db = new ModelContainer())
    {
        var account = db.Accounts.SingleOrDefault(a => a.ID == accountId);
        return (from d in account.Drafts
                let date = d.Date.Date
                where startDate.Date <= date && date <= endDate.Date
                orderby d.Date ascending
                select d).ToArray();
    }
}

protected void gridView_OnDataBinding(object sender, EventArgs e)
{
    ((IDataBoundControl)sender).DataSource = IoC.Resolve<IOperationRepository>().GetShared(this.ObjectId.Value, ucChooseDate.StartDate, ucChooseDate.EndDate);
}

answered Jan 31 '14 at 22:23

abatishchev

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Couple of questions; What's IDraft, are you using MVC and why is your method better than this method? http://stackoverflow.com/questions/554649/how-to-bind-linq-data-to-dropdownlist – Jan 31 '14 at 22:28
@xphill64x: IDraft is a strongly-typed entity. You can use both strongly- and loosely-typed aka anonymous classes. – abatishchev Jan 31 '14 at 22:33
No, this is "classic" ASP.NET aka Web Forms. – abatishchev Jan 31 '14 at 22:33
I'm assuming this is in your code-behind; mind sharing your GridView in asp.net? I'm definitely missing something due to my limited understanding of asp. – Jan 31 '14 at 22:44
Right, code-behind to bind GridView from SQL Server using LINQ to Entities/Entity Framework. Initially this was written using SqlConnection/SqlCommand but later reworked to use ORM. – abatishchev Jan 31 '14 at 22:45
let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/46557/discussion-between-xphill64x-and-abatishchev) – Jan 31 '14 at 22:56

LINQ to XML binding to asp.Net DropDownList

1 Answers1