HangFire Class Library

question
1

I have been asked to add Hangfire functionality to an existing project. When I try to add it through Nuget “Install-Package Hangfire” I get an exception…

Install-Package : Unable to resolve dependencies. ‘jQuery 2.1.3’ is not compatible with
‘Microsoft.jQuery.Unobtrusive.Ajax 2.0.30116 constraint: jQuery (>= 1.4.4 && < 2.0.0)’.

I was wondering if i could create a class library to wrap Hangfire so I can meet its constraints and use it though a reference to my class library. If anyone has done this how did you expose the BackgroundJob.Enqueue method?

2

Hangfire doesn’t depend on jQuery or anything. It must be your project has some unresolved dependencies, so installation fails.

3

It may not be dependent on jQuery but when you install hangfire with Nuget Package Console it does check that constraint. The project is a solid in production program and sans hangfire it doesn’t have any unresolved dependencies. The version of jQuery that it uses is higher than 2.0. I wouldn’t want to move it to an earlier version because I’m new to the project and I don’t know what that may break. I thought I may be able to create a dll that wrapped hangfire but that isn’t working out so well either. They want access to the hangfire dashboard and I am getting another exception when I try that in my test project. I tried to popup the dashboard in a Windows.Forms.WebBrowser in the constructor for my dll.

namespace Hangfire
{
    public static class GlobalVar
    {
       public static string MY_DB = "Data Source=myComputername\\SQLEXPRESS;Initial Catalog=HangFireDemo;Integrated Security=True";
       public static Uri MY_URI = null;
    }

public class cHangfire
{
    public cHangfire(string connection, Uri Url)
    {
        GlobalVar.MY_DB = connection;
        GlobalVar.MY_URI = Url;
        //Display Dashboard
        WebBrowser wb = new WebBrowser();
        wb.Navigate(GlobalVar.MY_URI);
        wb.Show();
    }

    public void Move(string Cdir, string Qdir, string Ddir)
    {
        string fileName = Cdir.Substring(Qdir.Length + 1);
        BackgroundJob.Enqueue(() => Directory.Move(Cdir, Path.Combine(Ddir, fileName)));
    }       
}

}

An exception of type ‘System.Threading.ThreadStateException’ occurred in System.Windows.Forms.dll but was not handled in user code
Additional information: ActiveX control ‘8856f961-340a-11d0-a96b-00c04fd705a2’ cannot be instantiated because the current thread is not in a single-threaded apartment.

4

Maybe I am missing what you are trying to do but you do not need the full Hangfire nuget package for this I think. You can just use Hangfire.Core and the storage DLL (like Hangfire.Sqlserver or Hangfire.Mongo) to get what you need to be able to enqueue jobs. I assume in this that you have the actual execution of jobs (i.e. the JobServer and optionally Dashboard) running in a different application (either ASP.NET app or Selfhosted).

I am also confused about the JQuery thing, it did not bother with it in any of my projects so far at any stage. Perhaps you can try adding

<AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>

to the VS project file. With the latest .Net versions (4.7.1 and 4.7.2.preview) there is a bit of a shift going on with which packages are now incorporated into the .NET runtime/sdk as opposed to being Nuget packages so this setting also helps a lot with that in my experience. Your mileage may vary.

Running it in a UI (such as a Winforms app) would not be advisable probably. As to your ThreadStateException this is not a Hangfire issue, it’s just a thing with the ActiveX you are trying to use, similar to webbrowser control in a new thread.