LinQ to XML query

Question

I am using LinQ to XML to populate a dropdown list when my page loads. How can I cache the results so that I don't have to run the query each and every time the page loads? Also the xml file will only be updated once a day. Is it better to cache or just read it each time?

Answer 1

Using standard caching techniques. Please see this post.

Answer 2

Call ToList() on the results of the query. Then cache the results in a static variable, accessed in a thread-safe way:

private static List<Whatever> dropDownListValues;
private static object listLock = new object();

public static IList<Whatever> DropDownListValues
{
    get
    {
        lock(listLock)
        {
            if (dropDownListValues == null ||
                DetectValuesChanged()) // However you implement this!
            {
                dropDownListValues = // insert your query here
                                        .ToList();
            }
            return dropDownListValues;
        }
    }
}