Clever Geek Handbook

C # Func <> Problem setting delegate properties

I am trying to return an object of type IDocumentTemplateProvider using a delegate as shown below:

public static class DocumentTemplateProvider
{
    private static Func<IDocumentTemplateProvider> _docTemplateProvider;

    public static void SetdocTemplateProvider(Func<IDocumentTemplateProvider> docTemplateProvider)
    {
        _docTemplateProvider = docTemplateProvider;
    }

    public static void SetDocTemplateProvider<T>() where T : IDocumentTemplateProvider, new()
    {
        _docTemplateProvider = () => new T();
    }

    public static IDocumentTemplateProvider TemplateProvider
    {
        get { return _docTemplateProvider(); }
    }
}

However, when I call it using:

private static readonly IDocumentTemplateProvider _template = DocumentTemplateProvider.TemplateProvider;

_template is always null. I'm new to C # Func <> delegates so I can't figure out what I'm doing wrong. Can anyone point me in the right direction?

thank

UPDATE: To clear up the ant confusion, I added the complete code where the _template is initialized and used as is:

 public class DocumentModule : IHttpModule
{
        private static readonly IDocumentTemplateProvider _template = DocumentTemplateProvider.TemplateProvider;

        public void Init(HttpApplication context)
        {
            context.BeginRequest += OnBeginRequest;
            context.EndRequest += OnEndRequest;
        }      

        public void Init(HttpApplication context)
        {
            context.BeginRequest += OnBeginRequest;
            context.EndRequest += OnEndRequest;
        }

        private void OnBeginRequest(object sender, EventArgs eventArgs)
        {
            _template.SetProvider();
        }

        private void OnEndRequest(object sender, EventArgs e)
        {
            _template.Finalize();
        }        

        public void Dispose()
        {
        }
}
+3


source share


1 answer


This is null because it has never been set. You have two Void methods that set the _docTemplateProvider variable so you need to call them first like the example code below



class Program
{
    private static void Main()
    {
        DocumentTemplateProvider.SetDocTemplateProvider<Test>();
        //OR
        DocumentTemplateProvider.SetdocTemplateProvider(() => new Test());

        IDocumentTemplateProvider _template = DocumentTemplateProvider.TemplateProvider;

        Console.ReadLine();
    }

    public static class DocumentTemplateProvider
    {
        private static Func<IDocumentTemplateProvider> _docTemplateProvider;

        public static void SetdocTemplateProvider(Func<IDocumentTemplateProvider> docTemplateProvider)
        {
            _docTemplateProvider = docTemplateProvider;
        }

        public static void SetDocTemplateProvider<T>() where T : IDocumentTemplateProvider, new()
        {
            _docTemplateProvider = () => new T();
        }

        public static IDocumentTemplateProvider TemplateProvider
        {
            get { return _docTemplateProvider(); }
        }
    }
}

internal interface IDocumentTemplateProvider
{
}

public class Test : IDocumentTemplateProvider
{
}
+1


source






More articles:


All Articles