XAF0004: Implement XAF controller constructors correctly

• Oct 26, 2021

Severity: Error

XAF requires that the controller’s constructor should be public and have no parameters.

If the controller’s class constructor does not meet these requirements, the class is not recognized as a controller.

This diagnostic works only for classes derived from the DevExpress.ExpressApp.Controller class. This diagnostics does not work for abstract classes.

Examples

Invalid Code

C#

using DevExpress.ExpressApp;
using DevExpress.Persistent.BaseImpl;

namespace MySolution.Module.Controllers{
    public class ExampleClass1 : Controller {
        // The constructor must be public
        // ExampleClass1 () {} // Error: XAF0004
    }

    public class ExampleClass2 : Controller {
        // The constructor must be without parameters, Dependency Injection is not supported.
        // public ExampleClass2 (IXafApplicationProvider appProvider){} // Error: XAF0004 
    }
    // ...
}

Valid Code

C#

using DevExpress.ExpressApp; 
using DevExpress.Persistent.BaseImpl; 

namespace MySolution.Module.Controllers {
    public class ExampleClass1 : Controller {
        // This constructor meets the requirements
        public ExampleClass1() {}
    }
    // ...
}

How to Fix

Declare the controller’s constructor with the public keyword and without parameters.