DataBind和/或asp：Repeater的迭代器整数

Question

I have a LINQ query that returns a custom object. The object is derived from a Dictionary<T> of result objects, each with a URL. My LINQ object groups the Dictionary<T> according to a URL property in T, and then takes the object.First() item from the Group of URLs.

Now I have a LINQ object all with unique URLs, and a count too of how many times the URL was repeated in the original Dictionary<T>.

Ok, at this point I perform a DataBind on my LINQ object, to an ASP page. The DataBind is to an <asp:Repeater> with an ItemTemplate .

What I want is to get the iterator of the <asp:Repeater> as if it is a simple for (int i = 0; ... i++) type loop. This is so I can dynamically display the number of the result (say if there was a list of five results, each result would have 1. Result .... 2. Result .... 3. Result ...

I do not know how many result will be there to start with (there could be none).

How could this be achieved? Could I use a lambda expression to alter the results object and hold an integer for its position in my Linq list??

I hope this isn't too confusing! Please ask if you need a better explanation. Much appreciated, as always.

Answer 1

If you want to display the row number in Repeater it is actually a lot easier than I think you realize. You don't need to know the current index since you can count / increment a value everytime a bind occurs and display it.

First create a integer in your .cs code. Eg:

public partial class _YourPageName : System.Web.UI.Page
{
    private int _itemCounter = 0;

Then in your Repeater ItemTemplate you just need to display it using a Literal or something.

<asp:Literal ID="litCount" runat="server" OnDataBinding="litCount_DataBinding" />

Then implement it the DataBinding event for the Literal or whatever you want to use:

protected void litCount_DataBinding(object sender, System.EventArgs e)
{
    _itemCounter++;
    Literal lt = (Literal)(sender);
    lt.Text = _itemCounter.ToString();
}

Each time the ItemTemplate is bound it will increment the counter and display it.

Maybe I am over simplifying your issue though.

Answer 2

It's not entirely clear what you're doing, particularly as you've referred to Dictionary as if it had one type parameter instead of two, but you might want to consider this:

var items = originalItems.Select((Value, Index) => new { Value, Index });

That overload of Select provides the index for each entry as it iterators - and I've just captured the results in an anonymous type. (You might want to use a Tuple<,> instead if you're using .NET 4; it depends on where the results will be used.)

This will start at Index=0 of course - to start from 1 you'd need:

var items = originalItems.Select((Value, idx) => new { Value, Index = idx + 1 });

(Parameter renamed to keep it on one short line for Stack Overflow.)