This is a lightweight implementation of the Freezable class. A freezable class is initially freely modifiable, but can be made read-only with freezing it.
The IFreezable interface describes a freezable class, the FreezableBase abstract class is a good base for freezable classes.


public abstract class MyFreezable : FreezableBase
    private string _data;
    public string Data
        get { return _data; }
            // This method will throw ReadonlyException if the object's Freeze() method was called.
            _data= value;


Various extensions methods that enhance built-in functionality. Don't forget to add the
using Piedone.HelpfulLibraries.Utilities;
declaration to your code.


// CacheServiceMonitor
// If the event is triggered the entry for the cache key will be removed.
_cacheService.Monitor("event key", "cache key");
// Removes all cache entries that were subscribed to the specified event.
_cacheService.Trigger("event key");

// HqlQueryExtensions
// From a Projector IFilterProvider
public void ApplyFilter(FilterContext context)
    IEnumerable<int> ids = ...
    context.Query.WhereIdIn(ids); // Applies the IN() in partitions of given size so the maximal number of IN() arguments isn't an issue.
// HqlExpressionFactoryExtensions has an extension to use such partitioned clauses in a generic way.

// UriExtensions
var urlWithoutSchema = new Uri("http://orchardproject.net").ToStringWithoutScheme();

// WebViewPageExtensions
if (this.WasNotDisplayed("myKey"))
    // Display something that should only be displayed once, no matter how many times the view is rendered

// Usable in a views, similar to the built-in Capture() method.
@using (this.CaptureOnce())
    // This will be included in the resulting html markup only once, no matter how many times the block is run.

See this blogpost for a sample usage of CaptureOnce().


Service for managing ORM mappings, particularly for clearing NHibernate mappings by deleting mappings.bin. Can be useful if you want to use new mappings immediately their update (e.g. inside a migration).
_mappingsManager.Clear(); // _mappingsManager is an injected IMappingsManager instance


A simple helper for determining the MIME type of a file, depending on its extension. Its code is taken from a SO post.
var mime = MimeAssistant.GetMimeType("test.jpg"); // image/jpeg


The following code returns the version of the currently executing Orchard application.
var version = OrchardVersion.Current();


Combines uri segments with forward slashes (much like Path.Combine() for local paths).
var uri = UriHelper.Combine("sub", "folder"); // Returns sub/folders


ILocalizerDependency can be used to inject a Localizer through ctor injection (instead of the usual property injection) or to enable explicit Resolve<T>()-ing of it.

Last edited Feb 23, 2014 at 11:34 PM by Piedone, version 15


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