Entity Framework Dynamic Filters Discover How to Filter Your Query

Definition

Entity Framework Dynamic Filters is a library that Creates global and scoped filters for Entity Framework queries.

The filters are automatically applied to every query and can be used to support use cases such as Multi-Tenancy, Soft Deletes, Active/Inactive, etc.

How It Works?

The library will add extensions methods automatically to DbContext and DbModelBuilder classes to access Dynamic Filters.

• Filters are defined in DbContext.OnModelCreating().
• Filters can be created using boolean LINQ expressions.
• It also supports the Contains() operator to define filters.

Filters can be defined on a specific entity class or an interface by providing a specific value.

include template-example.html%}

modelBuilder.Filter("IsDeleted", (ISoftDelete d) => d.IsDeleted, false);

This filter will apply to all classes that implements ISoftDelete.

Enabling and Disabling Filters

Filter can be easily disabled by using the DbContext.DisableFilter extension method. To disable a filter globally, use DbModelBuilder.DisableFilterGlobally method after it is created in OnModelCreating

include template-example.html%}

context.DisableFilter("IsDeleted");

//Disable a filter globally
modelBuilder.DisableFilterGlobally("IsDeleted");

You can also enable/disable all filters at once within a context.

include template-example.html%}

context.DisableAllFilters();
context.EnableAllFilters();

Conditionally Enabling Filters

Filters can also be enabled conditionally and you will even need to define those conditions along with your filter definition.

include template-example.html%}

modelBuilder.Filter("BlogEntryFilter", (BlogEntry b, Guid accountID) => (b.AccountID == accountID), 
                    () => GetPersonIDFromPrincipal(Thread.CurrentPrincipal));
modelBuilder.EnableFilter("BlogEntryFilter", () => !UserIsAdmin(Thread.CurrentPrincipal));

In this example, a filter is defined on BlogEntry records to restrict to only the current AccountID. But the filter will only be enabled if the user is not an Admin user.

Requirements

Entity Framework Version

• Entity Framework Core 2.x
• Entity Framework 6.x

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