Dependency Injection: Use of Dependency Injection

To use dependency injection in a class, you define a property of this class and assign the InjectDependency attribute to this property.

Applicable Classes

You can use dependency injection in:

• A graph
• A graph extension
• An attribute derived from PXEventSubscriberAttribute
• A custom action class derived from the PXAction class or its descendants
• A PXSelectBase-derived class
• a PX.Tests.Unit.TestBase-derived class

Use of Dependency Injection During Graph Initialization

The properties to which the InjectDependency attribute is assigned cannot be used in graph constructors. If you need to use these properties during the initialization of a graph, you need to implement the IGraphWithInitialization interface in the graph. You can use the properties in the implementation of the IGraphWithInitialization.Initialize() method.

Examples

The following code shows definitions of the property with the InjectDependency attribute in various classes.

using System;
using PX.Data;

namespace MyNameSpace
{
    //Dependency injection in a graph
    public class MyGraph : PXGraph<MyGraph>
    { 
        [InjectDependency]
        private IMyService MyService { get; set; }

        public PXAction<MyDAC> MyButton;
        [PXButton]
        [PXUIField(DisplayName ="My Action")]
        protected void myButton()
        {
            MyService.ProvideServiceFunctions();
        }

        //Other code of the graph
    }

    //Dependency injection in a graph extension
    public class MyGraphExtension : PXGraphExtension<MyGraph>
    {
        [InjectDependency]
        private IMyService MyService { get; set; }

        //Other code of the graph extension
    }

    //Dependency injection in a custom attribute
    public class CustomAttribute : PXEventSubscriberAttribute
    {
        [InjectDependency]
        public IMyService Service { get; set; }

        //Other code of the attribute
    }

    //Dependency injection in a custom action class
    public class CustomCancel<T> : PXCancel<T> 
        where T: class, IBqlTable, new()
    {
        [InjectDependency]
        public IMyService Service { get; set; }

        //Other code of the custom action class
    }

    //Dependency injection in a PXSelectBase-derived class
    public class MySelect<Table> : PXSelectBase<Table>
        where Table : class, IBqlTable, new()
    { 
        [InjectDependency]
        private IMyService MyService { get; set; }

        //Other code of the class
    }

    //Dependency injection in a PX.Tests.Unit.TestBase-derived class
    public class MyTestClass : PX.Tests.Unit.TestBase
    { 
        [InjectDependency]
        private IMyService MyService { get; set; }

        // Other code of the test class
    }
}