I have a WPF based UI which has a navigation bar. The UI uses a WCF service with a State Machine Workflow. The WPF application is a data capture wizard sort of application. As the user goes through different states the Navigation bar shows the states(user journey or breadcrumb). At any point the user can click on any of the previously visited states to Navigate back to the state.
Using WF4, is it possible to Jump to any state without having a Transition? Another scenario is that I do not want to use the Persistence and just store the "Last State Name". Later when the user wants to resume the workflow, I just want to instantiate a new instance of the workflow and jump to the State using the stored "Last State Name" and resume the workflow.
Thanks.
I found this which is exactly what I am after but since it was posted in 2011, was wondering if there is anything new released to do the same.
http://code.msdn.microsoft.com/Windows-Workflow-233b5e3c#content
Related
I'm using ASP.NET WebForms.
In PostBack I create a Task(task is very long running).
In the html page I need a button that can cancel this task.
1. I click button GetResults that Run a task on the server
2. After some waiting I click button Cancel and I need the task will be cancelled
How can I do this?
Though, you can do it, it is generally not a good idea to create a long running task within ASP.NET, especially if they are background tasks.
Phil Haack has a great article on this - http://haacked.com/archive/2011/10/16/the-dangers-of-implementing-recurring-background-tasks-in-asp-net.aspx/
Here is another good article on that topic - http://blog.stephencleary.com/2012/12/returning-early-from-aspnet-requests.html
You can consider things like message bus for this. You can also consider a simple TaskQueue table in the database to which your web application will insert a record corresponding to your task with status "Pending". Then you can have a background service (like windows service) that reads "Pending" tasks and marks them as "InProgress" during processing and "Complete" when its done. That way while the task is "Pending", you can have the user cancel the task from UI, which will simply delete the "Pending" record from the database.
Another option is to use a solution such as this - http://hangfire.io/
I have created a simple workflow start-->createoredit-->automaticactivity-->End. automatic activity doesnt do anything, i have default code in the script area of automati activity FinishActivity "Automatic Activity Finished" alone in the script area.
When i trigger the workflow, automatic activity is not started and performed, it is assigned to "NTAUTHORITY SYSTEM" with the state "Assigned" (In the Global Work List)
Whenever i restart the "Tridion Workflow Agent" service or whenever some other automatic activity assigned via workflow, automatic activity start performed.
I dont see any error message also in the event log.
Could anyone help me on this? I am using SDL Tridion 2011 SP1.
The first activity must always be a manual activity. If you need to have the first activity automated then you need to rely on the event system for this.
EDIT: I see you wrote the question to add the first activity to be manual.
When an automatic activity gets stuck in Assigned state, it usually means there is a script error. There could also be something with the connectors between activities in your Visio design. Check that everything us properly connected. Try deleting the link between automaticactivity to End and recreating it again.
Check that the "Tridion Content Manager Workflow Agent" windows service is running. This fixed it for us.
This is probably a really simple thing. Basically, the user clicks a button and a potentially long running task happens. I'd like to do a few things like toggle the button's enabled state, show a spinner, etc. In VB.NET Winforms I'd just do Application.DoEvents() and the updates would happen and the code can continue. How can I do this in ASP.NET? (preferable serverside or minimal javascript)
There are a few ways to approach this in ASP.Net depending on exactly what your requirement is. Getting the process started is fairly easy, but monitoring it for completion from the client side will require more work in both the server and the client.
The basic outline of the solution is:
1) Perform some action on the client that initiates the action. For example, you could post the entire page back on a button click, initiate an ajax request, or have a partial page postback depending on how much information you need from the page.
2) On the server side, initiate the task using a BackgroundWorker, make an entry in a workflow queue, or store a request in a database table that is monitored by a service that is responsible for performing the action.
3) Back on the client side, use javascript start a window.timeout loop that, when it times out, issues an ajax request to the web server to check on the completion. Using a timeout loop like this will ensure that the UI remains responsive and that any animations being displayed will display correctly. How you check on the completion will depend on how your server-side implementation is designed, but will almost certainly require a database.
We use the following general approach for initiating reports from the web client, which can be long running:
When the user initiates the report, open a new window to the report generation page on the client using javascript, passing the page enough parameters to get it started. Opening a separate window allows the user to continue working, but still see that there is something happening.
The user interface for the report page basically contains an animated GIF so that the user knows that something is going on.
When the report page is initially loaded on the server, it generates a unique id for monitoring the status of the report and embeds this in javascript for use in monitoring the status. It then stores this unique identifier in a database table that contains the unique id and a status column, initializing the status to requested.
Once the database entry has been made, the page fires off a BackgroundWorker to initiate the action and then returns the page to the user.
When the page is displayed, javascript starts a window.timeout loop that periodically fires off an ajax request to the web server, which then checks the database for the status of the report using the unique identifier created earlier.
When the backgroundworker finishes the report, either successfully or in failure, it updates the database table with the status, location of the report or error messages and terminates.
When the javascript loop finds that the report generation has completed, it either displays the error message or the report to the user.
Hopefully, this gives you some ideas for solving your issue.
The issue with this could be that once the page is posting you can't update other sections of the page.
you can use multiple asp:updatepanel and communicate to other update panel's causing the state to change in the panel.
take a look at this link:
http://www.ajaxtutorials.com/ajax-tutorials/tutorials-using-multiple-updatepanels-in-net-3-5-and-vb/
it will show you how to accomplish this.
I have a asp .net master page application and one content page has a number of controls on it.
I want to store the content/state of those controls in the session state whenever a user navigates to another content page.
My question is, how do I know when to capture the control state? Is there an event of some type I can use to trigger a procedure?
Thanks in advance for any info.
Bill
There aren't any real "global" server side event handlers that you can use to detect when the user is going to another page (or even just hitting the back button in the browser).
The best bet is to simply write a method in your master page that will save your session state and then execute a Response.Redirect() to the location specified. Then make all of your links go through this method when you need to track session state.
Presumably they are navigating away from that page via a control that you have provided them (button, link, etc.) You can trap the action on the server side at that point and cache your state.
What about using session variables?
See this link for more info:
ASP.Net Session
There's a number of ways to maintain state. There are trade-offs no matter which version you use. For example, I wouldn't use session variables on an app that is load-balanced across multiple servers; you're not guaranteed to get the same server for each request, and the state is stored on a server-by-server basis.
It's hard to beat this
Session["myState"] = 7; // bad example
for simplicity, though. :)
I’ve been asked if we can optionally “single-instance” our web portal. See
this post on Hanselman's blog for the same idea in a WinForms app.
Suppose we have 2 shortcuts on the same client machine:
http://MyServer/MyWebPortal/Default.aspx?user=username&document=Foo
http://MyServer/MyWebPortal/Default.aspx?user=username&document=Bar
Clicking on the first shortcut would launch our web portal, log in, and display the document “Foo”. Clicking on the second shortcut should display the document “Bar” in the running instance of the web portal.
My current approach is this: In the Page Load, for the first instance create a per-client Application variable. The second instance looks for the Application variable to see if the portal is running on the client. If it is, the second URL is recorded in another Application variable and the second instance is forcibly exited. I’ve tried creating a ASP.Net AJAX Timer to poll the Application variable for a document to display. This sort of works. In order to respond quickly to the second request I’ve set the Timer interval to 2 seconds. This makes the portal irritating to use because of the frequent postbacks.
Using my approach, is there a way for the second instance to notify the first instance to check the application variable without polling? Is there a better overall approach to this problem?
Thanks in advance
There is no way on the server side to control which browser instance your page opens up on the client. You can't force all requests to open in the same browser window.
Also, an Application scope variable is shared by all users of your application. At least make this a Session-scope variable - otherwise you would only be allowing one user to access your portal at a time!
Honestly this sounds like a silly request from someone who a) probably doesn't understand how these types of things work and b) is trying to do an end-around for users who aren't that bright and actually see a problem with having more than one instance of your portal open.