Question

I have a question that’s so simple I cannot believe I can’t answer it myself. But, there you go.

I have a large-ish static list (of cities, latitudes and longitudes) that I want to use in my Windows Phone 7 Silverlight application. There are around 10,000 of them. I’d like to embed this data statically in my application and access it in an array (I need to cycle through the whole list in code pretty regularly).

What is going to be my most effective means of storing this? I’m a bit of an old school sort, so I reckoned the fastest way to do it would be:

public struct City
{
    public string name;
    public double lat;
    public double lon;
};

and then…

private City[] cc = new City[10000];

public CityDists()
{
    cc[2].name = "Lae, Papua New Guinea"; cc[2].lat = 123; cc[2].lon = 123;
    cc[3].name = "Rabaul, Papua New Guinea"; cc[3].lat = 123; cc[3].lon = 123;
    cc[4].name = "Angmagssalik, Greenland"; cc[4].lat = 123; cc[4].lon = 123;
    cc[5].name = "Angissoq, Greenland"; cc[5].lat = 123; cc[5].lon = 123;
...

However, this bums out with an “out of memory” error before the code actually gets to run (I’m assuming the code itself ended up being too much to load into memory).

Everything I read online tells me to use an XML resource or file and then to deserialise that into instances of a class. But can that really be as fast as using a struct? Won’t the XML take ages to parse?

I think I’m capable of writing the code here – I’m just not sure what the best approach is to start with. I’m interested in speed of load and (more importantly) run time access more than anything.

Any help very much appreciated – first question here so I hope I haven’t done anything boneheaded.

Chris

Answer 1

If loading an xml doc from the xap works for you..

Here’s a project I posted demonstrating loading of an xml doc from the XAP via XDocument/LINQ and databinding to a listbox for reference.

binding a Linq datasource to a listbox