Hey experts.
After my last post, the flue got me and knocked me out. I'm awake for the first time in two days, and first thing I did was play around with this... <= geek.
Anyways, I did get this working, using the code below (I'll post about it in detail & will actually release it as an extension, links on the way):
public partial class StudentsListDetail
{
partial void StudentsListDetail_Activated()
{
//Use reflection to find the CollectionLoader
var t = this.Students.Screen.Details.Properties.All().FirstOrDefault();
var prop = t.GetType().GetProperty("CollectionLoader", BindingFlags.GetField | BindingFlags.Instance | BindingFlags.NonPublic);
var loader = prop.GetValue(t, null) as IScreenCollectionPropertyLoader;
//Use the main dispatcher (who owns the CollectionLoader) to listen for changes
Microsoft.LightSwitch.Threading.Dispatchers.Main.BeginInvoke(
() =>
{
loader.PropertyChanged += loader_PropertyChanged;
}
);
}
void loader_PropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (e.PropertyName == "SearchTerms")
{
//Upon change, we replace the SearchTerms. This in turn, fires the PropertyChanged event again.
//To avoid endless loops: behold the ignoreNextSearchTermChangedEvent boolean!
if (ignoreNextSearchTermsChangedEvent)
{
ignoreNextSearchTermsChangedEvent = false;
}
else
{
IScreenCollectionPropertyLoader loader = sender as IScreenCollectionPropertyLoader;
List<SearchTerm> fuzzyTerms = new List<SearchTerm>();
foreach (var searchTerm in loader.SearchTerms)
{
fuzzyTerms.Add(MakeFuzzy(searchTerm));
}
loader.SetSearchTerms(fuzzyTerms);
ignoreNextSearchTermsChangedEvent = true;
}
}
}
My question is though: am i correct that I have to use reflection to find the CollectionLoader? IScreenCollectionPropertyLoader is a public interface, so it doesn't feel natural to have to use reflection. Or is it indeed the only way?
By the way, this implementation is doing exactly what Justin wrote:There is no (reasonable) way
to intercept the search terms or modify the generated search query. I say "no (reasonable) way" because it is theoretically possible to listen for when the SearchTerms property changes on the IScreenCollectionPropertyLoader to which the
data grid or list control is bound and reset the terms to the new terms you want. If you get this working, it should have the effect of tossing away the terms that the user enters and displays the terms that you have set. In any case, you cannot intercept
the generated query and rewrite it before it is sent to the data source.
Thanks again!
Jan
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