DependencyAttribute Class

This attribute is used to mark properties and parameters as targets for injection.

Namespace:  Microsoft.Practices.Unity
Assembly:  Microsoft.Practices.Unity (in Microsoft.Practices.Unity.dll)

[AttributeUsageAttribute(AttributeTargets.Property|AttributeTargets.Parameter, AllowMultiple = false, 
	Inherited = true)]
public sealed class DependencyAttribute : DependencyResolutionAttribute

For properties, this attribute is necessary for injection to happen. For parameters, it's not needed unless you want to specify additional information to control how the parameter is resolved.