corelibraries-devexpress-dot-dataaccess-dot-entityframework-dot-efdatasource.md
Occurs on an attempt to load a custom assembly by EFDataSource in the Data Source Wizard.
Namespace : DevExpress.DataAccess.EntityFramework
Assembly : DevExpress.DataAccess.v25.2.dll
NuGet Package : DevExpress.DataAccess
public event BeforeLoadCustomAssemblyEventHandler BeforeLoadCustomAssembly
Public Event BeforeLoadCustomAssembly As BeforeLoadCustomAssemblyEventHandler
The BeforeLoadCustomAssembly event's data class is BeforeLoadCustomAssemblyEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| AllowLoading | Specifies whether loading a custom assembly is allowed. |
| AssemblyPath | Specifies the path to a requested assembly. |
| ContextName | Specifies the type to load from a custom assembly. |
Loading of custom assemblies that may be referenced by Entity Framework data sources is forbidden by default.
To permit loading a specific assembly in the Data Source Wizard, handle the BeforeLoadCustomAssembly event (or static EFDataSource.BeforeLoadCustomAssemblyGlobal event) and specify the following properties of the BeforeLoadCustomAssemblyEventArgs object.
An unauthorized attempt to load a custom assembly will result in throwing a CustomAssemblyLoadingProhibitedException.
In the Data Source wizard, the corresponding option is disabled so that end-users are only allowed to select a data context from assemblies referenced by the project.
To make the Browse button visible, set the EFWizardSettings.ShowBrowseButton property to true.
See Also
BeforeLoadCustomAssemblyGlobal