The `Task` class is an improvement over the `BackgroundWorker`; it naturally supports nesting (parent/child tasks), uses the new cancellation API, task continuations, etc.

[I have an example on my blog][1], showing the old `BackgroundWorker` way of doing things and the new `Task` way of doing things. I do have a small helper class for tasks that need to report progress, because I find the syntax rather awkward. The example covers result values, error conditions, cancellation, and progress reporting.


  [1]: http://blog.stephencleary.com/2010/06/reporting-progress-from-tasks.html

Background worker is still a valid way of achieving this - if you are running multiple large operations concurrently then the parallel extensions would be worth considering, if its just the one then I would stick with the backgroundworker.

Can I completely rely upon jQuery&#39;s `html()` method behaving identical to `innerHTML`? Is there any difference between `innerHTML` and jQuery&#39;s `html()` method? If these methods both do the same, can I use jQuery&#39;s `html()` method in place of `innerHTML`?

My problem is: I am working on already designed pages, the pages contains tables and in JavaScript the `innerHTML` property is being used to populate them dynamically.

The application is working fine on *Firefox* but *Internet Explorer* fires an error: `unknown runtime exception`. I used jQuery&#39;s `html()` method and *IE*&#39;s error has disappeared. But I&#39;m not sure it will work for all browsers and I&#39;m not sure whether to replace all `innerHTML` properties with jQuery&#39;s `html()` method.

Thanks a lot.


JQuery html() vs. innerHTML

what I want to do is construct a moq for I1 - which is fine ... however in the course of the method that I am testing that uses this mock I need to cast it to I2 in order to access some properties that are not on I1

    Interface I1 
    { int AProperty{get;set;}}
    
    Interface I2
    {int AnotherProperty{get;set;}}

I then have some objects

    Class O1 : I1 {}

and 

    Class O2 : O1 , I2 {}

the problem is that when i have an instance of a I2 implementing object I can cast it to I1 in order to access the methods that are implmented through that interface. In code this is not a problem and everythign works as expected.

The only problem comes when writing a unit test on that class.

The interfaces also expose a method called GetNewInstance which returns an initialised instance of the the implementing object cast into the IGetNewInstance&lt;T&gt; interface ... i can usually mock this fine and make it return itself (and so I keep working with the mock object).

however when you try to cast this returned object of type I2 into I1 a null reference results - this makes sense as the mock object that implements I2 does not inherit from anything that inherits I1.

the question is how can i force the mock object to inherit from both I1 ansd I2 at the same time?

MOQ - how to mock an interface that needs to be cast to another interface?

Does the task parallel library have anything that would be considered a replacement or improvement over the BackgroundWorker class? 

I have a WinForms application with a wizard-style UI, and it does some long-running tasks. I want to be able to have a responsive UI with the standard progress bar and ability to cancel the operation. I&#39;ve done this before with BackgroundWorker, but I&#39;m wondering if there are some TPL patterns that can be used instead?

Task parallel library replacement for BackgroundWorker?

<p>Does the task parallel library have anything that would be considered a replacement or improvement over the BackgroundWorker class?</p>
<p>I have a WinForms application with a wizard-style UI, and it does some long-running tasks. I want to be able to have a responsive UI with the standard progress bar and ability to cancel the operation. I've done this before with BackgroundWorker, but I'm wondering if there are some TPL patterns that can be used instead?</p>


When I try to build my solution, I get the following error:

&gt;Visual Studio cannot start debugging because the debug target &#39;c:\target&#39; is missing. Please &gt;build the project and retry, or set the OutputPath and AssemblyName properties appropriately &gt;to point at the correct location for the target assembly.  

My output path is set correctly to **bin\Debug**, but the exe is never created in that folder.  Instead, all I get are the `exe.config`, `vshost.exe`, and `vshost.exe.config` files.

Any idea what&#39;s going on?

Debug Target Is Missing?

I want to check if a String s, contains &quot;a&quot; or &quot;b&quot; or &quot;c&quot;, in C#.
I am looking for a nicer solution than using
 
    if (s.contains(&quot;a&quot;)||s.contains(&quot;b&quot;)||s.contains(&quot;c&quot;))


How to check if a String contains any of some strings

Will it only return false if the dictionary does not contain a value for the given key or will it also return false due to thread race conditions, like another thread adds/updates something?

Question in code:

    ConcurrentDictionary&lt;int, string&gt; cd = new ConcurrentDictionary&lt;int, string&gt;();

    // This might fail if another thread is adding with key value of 1.
    cd.TryAdd(1, &quot;one&quot;); 

    // Will this ever fail if no other thread ever removes with the key value of 1?
    cd.TryRemove(1); 

**Edit:**
I think that it only will return false if it does not contain a value for the given key, but want to be absolutely sure.

When will ConcurrentDictionary TryRemove return false

I have a small form, which comes up when I press a button in a Windows Forms application.

I want to be able to close the form by pressing the escape key. How could I do this? I am not sure of the event to use. form_closing?


How to make a form close when pressing the escape key?

&gt; **Possible Duplicate:**  
&gt; https://stackoverflow.com/questions/163162/can-you-call-directory-getfiles-with-multiple-filters  

&lt;!-- End of automatically inserted text --&gt;

How do you filter on more than one extension?

I&#39;ve tried:

    FileInfo[] Files = dinfo.GetFiles(&quot;*.jpg;*.tiff;*.bmp&quot;);
    FileInfo[] Files = dinfo.GetFiles(&quot;*.jpg,*.tiff,*.bmp&quot;);


GetFiles with multiple extensions

I have used ProgressBar Control in my c# desktop application.I have used it in a thread other then the thread in which control has been declared.Its working Fine.
Now I am wondering how i can show some text inside progress bar control like &quot;Initiating Registration&quot; etc.Also I want to use it as Marquee progress bar.Please help me. 

How do I put text on ProgressBar?

I am developing a windows application using C#. I am using `DataGridView` to display data. I have added a button column in that. I want to know how can I handle click event on that button in `DataGridView`.

How to handle click event in Button Column in Datagridview?

It&#39;s that simple. How do I get the index of the currently selected `Row` of a `DataGridView`? I don&#39;t want the `Row` object, I want the index (0 .. n).

Index of Currently Selected Row in DataGridView

I have a form with 2 comboboxes on it. And I want to fill `combobox2.DataSource` based on `combobox1.Text` and `combobox2.Text` (I assume that the user has completed input in `combobox1` and is in the middle of inputting in `combobox2`). So I have an event handler for `combobox2` like this:

    private void combobox2_TextChanged(object sender, EventArgs e)
    {
        if (cmbDataSourceExtractor.IsBusy)
           cmbDataSourceExtractor.CancelAsync();
    
        var filledComboboxValues = new FilledComboboxValues{ V1 = combobox1.Text,
           V2 = combobox2.Text};
        cmbDataSourceExtractor.RunWorkerAsync(filledComboboxValues );
    }

As far as building DataSource is time-consuming process (it creates a request to database and executes it) I decided that it&#39;s better to perform it in another process using BackgroundWorker. So there&#39;s a scenario when cmbDataSourceExtractor hasn&#39;t completed its work and the user types one more symbol. In this case I get an exception on this line  
`cmbDataSourceExtractor.RunWorkerAsync(filledComboboxValues );` about that BackgroundWorker is busy and cannot perform several actions in the same time.  
How to get rid of this exception?  
Thanks in advance!

How to stop BackgroundWorker correctly

Let&#39;s say I want to sent an int parameter to a background worker, how can this be accomplished?

    private void worker_DoWork(object sender, DoWorkEventArgs e) {

    }

I know when this is worker.RunWorkerAsync();, I don&#39;t understand how to define in worker_DoWork that it should take an int parameter.

Sending Arguments To Background Worker?

In my application I need to perform a series of initialization steps, these take 7-8 seconds to complete during which my UI becomes unresponsive. To resolve this I perform the initialization in a separate thread:

    public void Initialization()
    {
        Thread initThread = new Thread(new ThreadStart(InitializationThread));
        initThread.Start();
    }

    public void InitializationThread()
    {
        outputMessage(&quot;Initializing...&quot;);
        //DO INITIALIZATION
        outputMessage(&quot;Initialization Complete&quot;);
    }

I have read a few articles about the `BackgroundWorker` and how it should allow me to keep my application responsive without ever having to write a thread to perform lengthy tasks but I haven&#39;t had any success trying to implement it, could anyone tell how I would do this using the `BackgroundWorker`?

How to use WPF Background Worker

I know it has 3 methods. In my program I have a method to send a message. It is often late and the program sometimes doesn&#39;t send the message at all in response to a button press. At times it is as late as 5 seconds from what I would expect and the program freezes. I want to use a `BackgroundWorker` to send the message as expected and allow the program to run normally at all times. I had the code for sending the message in a button handler. Now where do I put this equivalent code? I would like all of this to still be handled by a button press.

Is this the appropriate handler?
   

    backgroundWorker1.RunWorkerAsync();


and in: 

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e) {}

I&#39;m going to put my code in the button handler?
And this before:

    carga.progressBar1.Minimum = 0;
    carga.progressBar1.Maximum = 100;

Carga is my other form where the ProgressBar is. How do I use a BackgroundWorker in this scenario?
      

How to use a BackgroundWorker?

My code is as below    

    public CountryStandards()
    {
        InitializeComponent();
        try
        {
            FillPageControls();
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message, &quot;Country Standards&quot;, MessageBoxButton.OK, MessageBoxImage.Error);
        }
    }
    
    /// &lt;summary&gt;
    /// Fills the page controls.
    /// &lt;/summary&gt;
    private void FillPageControls()
    {
        popUpProgressBar.IsOpen = true;
        lblProgress.Content = &quot;Loading. Please wait...&quot;;
        progress.IsIndeterminate = true;
        worker = new BackgroundWorker();
        worker.DoWork += new System.ComponentModel.DoWorkEventHandler(worker_DoWork);
        worker.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(worker_ProgressChanged);
        worker.WorkerReportsProgress = true;
        worker.WorkerSupportsCancellation = true;
        worker.RunWorkerCompleted += new System.ComponentModel.RunWorkerCompletedEventHandler(worker_RunWorkerCompleted);
        worker.RunWorkerAsync();                    
    }
    
    private void worker_DoWork(object sender, System.ComponentModel.DoWorkEventArgs e)
    {
        GetGridData(null, 0); // filling grid
    }
    
    private void worker_ProgressChanged(object sender, System.ComponentModel.ProgressChangedEventArgs e)
    {
        progress.Value = e.ProgressPercentage;
    }
    
    private void worker_RunWorkerCompleted(object sender, System.ComponentModel.RunWorkerCompletedEventArgs e)
    {
        worker = null;
        popUpProgressBar.IsOpen = false;
        //filling Region dropdown
        Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();
        objUDMCountryStandards.Operation = &quot;SELECT_REGION&quot;;
        DataSet dsRegionStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);
        if (!StandardsDefault.IsNullOrEmptyDataTable(dsRegionStandards, 0))
            StandardsDefault.FillComboBox(cmbRegion, dsRegionStandards.Tables[0], &quot;Region&quot;, &quot;RegionId&quot;);
    
        //filling Currency dropdown
        objUDMCountryStandards = new Standards.UDMCountryStandards();
        objUDMCountryStandards.Operation = &quot;SELECT_CURRENCY&quot;;
        DataSet dsCurrencyStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);
        if (!StandardsDefault.IsNullOrEmptyDataTable(dsCurrencyStandards, 0))
            StandardsDefault.FillComboBox(cmbCurrency, dsCurrencyStandards.Tables[0], &quot;CurrencyName&quot;, &quot;CurrencyId&quot;);
    
        if (Users.UserRole != &quot;Admin&quot;)
            btnSave.IsEnabled = false;
    
    }
    
    /// &lt;summary&gt;
    /// Gets the grid data.
    /// &lt;/summary&gt;
    /// &lt;param name=&quot;sender&quot;&gt;The sender.&lt;/param&gt;
    /// &lt;param name=&quot;pageIndex&quot;&gt;Index of the page.( used in case of paging)   &lt;/pamam&gt;
    private void GetGridData(object sender, int pageIndex)
    {
        Standards.UDMCountryStandards objUDMCountryStandards = new Standards.UDMCountryStandards();
        objUDMCountryStandards.Operation = &quot;SELECT&quot;;
        objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;
        DataSet dsCountryStandards = objStandardsBusinessLayer.GetCountryStandards(objUDMCountryStandards);
        if (!StandardsDefault.IsNullOrEmptyDataTable(dsCountryStandards, 0) &amp;&amp; (chkbxMarketsSearch.IsChecked == true || chkbxBudgetsSearch.IsChecked == true || chkbxProgramsSearch.IsChecked == true))
        {
            DataTable objDataTable = StandardsDefault.FilterDatatableForModules(dsCountryStandards.Tables[0], &quot;Country&quot;, chkbxMarketsSearch, chkbxBudgetsSearch, chkbxProgramsSearch);
            dgCountryList.ItemsSource = objDataTable.DefaultView;
        }
        else
        {
            MessageBox.Show(&quot;No Records Found&quot;, &quot;Country Standards&quot;, MessageBoxButton.OK, MessageBoxImage.Information);
            btnClear_Click(null, null);
        }
    }

The step `objUDMCountryStandards.Country = txtSearchCountry.Text.Trim() != string.Empty ? txtSearchCountry.Text : null;` in get grid data throws exception 

&gt; The calling thread cannot access this object because a different
&gt; thread owns it.

What&#39;s wrong here?


The calling thread cannot access this object because a different thread owns it

Certain `System.Threading.Tasks.Task` constructors take a `CancellationToken` as a parameter:

    CancellationTokenSource source = new CancellationTokenSource();
    Task t = new Task (/* method */, source.Token);

What baffles me about this is that there is no way from _inside_ the method body to actually get at the token passed in (e.g., nothing like `Task.CurrentTask.CancellationToken`). The token has to be provided through some other mechanism, such as the state object or captured  in a lambda.

So what purpose does providing the cancellation token in the constructor serve?

Cancellation token in Task constructor: why?

I want to trigger a task to run on a background thread. I don&#39;t want to wait on the tasks completion.

In .net 3.5 I would have done this:

    ThreadPool.QueueUserWorkItem(d =&gt; { DoSomething(); });

In .net 4 the TPL is the suggested way. The common pattern I have seen recommended is:

    Task.Factory.StartNew(() =&gt; { DoSomething(); });

However, the [`StartNew()`][1] method returns a [`Task`][2] object which implements `IDisposable`. This 
seems to be overlooked by people who recommend this pattern. The MSDN documentation on the [`Task.Dispose()`][3] method says:

&gt; &quot;Always call Dispose before you release your last reference to the Task.&quot;

You can&#39;t call dispose on a task until it is completed, so having the main thread wait and call dispose would defeat the point of doing on a background thread in the first place. There also doesn&#39;t seem to be any completed/finished event that could be used for cleanup.

The MSDN page on the Task class doesn&#39;t comment on this, and the book &quot;Pro C#2010...&quot; recommends the same pattern and makes no comment on task disposal.

I know if I just leave it the finalizer will catch it in the end, but is this going to come back and bite me when I&#39;m doing lots of fire &amp; forget tasks like this and the finalizer thread gets overwhelmed?

So my questions are: 

 - Is it acceptable to not call `Dispose()` on the `Task` class in this case? And if so, why and are there risks/consequences?
 - Is there any documentation that discusses this? 
 - Or is there an appropriate way of disposing of the `Task` object that I&#39;ve missed?
 - Or is there another way of doing fire &amp; forget tasks with the TPL?


  [1]: http://msdn.microsoft.com/en-us/library/dd321439.aspx
  [2]: http://msdn.microsoft.com/en-us/library/system.threading.tasks.task.aspx
  [3]: http://msdn.microsoft.com/en-us/library/dd270681.aspx

Is it considered acceptable to not call Dispose() on a TPL Task object?

I don&#39;t see the different between C#&#39;s (and VB&#39;s) new async features, and .NET 4.0&#39;s [Task Parallel Library][1]. Take, for example, Eric Lippert&#39;s code [from here][2]:

    async void ArchiveDocuments(List&lt;Url&gt; urls) {
        Task archive = null;
        for(int i = 0; i &lt; urls.Count; ++i) {
            var document = await FetchAsync(urls[i]);
            if (archive != null)
                await archive;
            archive = ArchiveAsync(document);
        }
    }

It seems that the `await` keyword is serving two different purposes. The first occurrence (`FetchAsync`) seems to mean, _&quot;If this value is used **later in the method** and its task isn&#39;t finished, wait until it completes before continuing.&quot;_ The second instance (`archive`) seems to mean, _&quot;If this task is not yet finished, wait **right now** until it completes.&quot;_ If I&#39;m wrong, please correct me.

Couldn&#39;t it just as easily be written like this?

    void ArchiveDocuments(List&lt;Url&gt; urls) {
        for(int i = 0; i &lt; urls.Count; ++i) {
            var document = FetchAsync(urls[i]);       // removed await
            if (archive != null)
                archive.Wait();                       // changed to .Wait()
            archive = ArchiveAsync(document.Result);  // added .Result
        }
    }

I&#39;ve replaced the first `await` with a `Task.Result` where the value is actually needed, and the second `await` with `Task.Wait()`, where the wait is actually occurring. The functionality is `(1)` already implemented, and `(2)` much closer semantically to what is actually happening in the code.

I do realize that an `async` method is rewritten as a state machine, similar to iterators, but I also don&#39;t see what benefits that brings. Any code that requires another thread to operate (such as downloading) will still require another thread, and any code that doesn&#39;t (such as reading from a file) could still utilize the TPL to work with only a single thread.

I&#39;m obviously missing something huge here; can anybody help me understand this a little better?

 [1]: https://docs.microsoft.com/en-us/dotnet/standard/parallel-programming/task-based-asynchronous-programming
 [2]: https://devblogs.microsoft.com/ericlippert/wp-login.php?redirect_to=/ericlippert/asynchronous-programming-in-c-5-0-part-two-whence-await

How does C# 5.0&#39;s async-await feature differ from the TPL?

In C# 4.0, we have `Task` in the *System.Threading.Tasks* namespace. What is the true difference between `Thread` and `Task`. I did some sample program(help taken from MSDN)  for my own sake of learning with 

    Parallel.Invoke 
    Parallel.For 
    Parallel.ForEach 

but have many doubts as the idea is not so clear. 

I have initially searched in Stackoverflow for a similar type of question but may be with this question title I was not able to get the same. If anyone knows about the same type of question being posted here earlier, kindly give the reference of the link.

What is the difference between task and thread?

I&amp;nbsp;want to wait for a [Task&amp;lt;T&amp;gt;][1] to complete with some special rules:
If it hasn&#39;t completed after X milliseconds, I&amp;nbsp;want to display a message to the user.
And if it hasn&#39;t completed after Y milliseconds, I&amp;nbsp;want to automatically [request cancellation][2].

I&amp;nbsp;can use [Task.ContinueWith][3] to asynchronously wait for the task to complete (i.e.&amp;nbsp;schedule an action to be executed when the task is complete), but that doesn&#39;t allow to specify a timeout.
I can use [Task.Wait][4] to synchronously wait for the task to complete with a timeout, but that blocks my thread.
How can I asynchronously wait for the task to complete with a timeout?

  [1]: http://msdn.microsoft.com/en-us/library/dd321424.aspx
  [2]: http://msdn.microsoft.com/en-us/library/dd321955.aspx
  [3]: http://msdn.microsoft.com/en-us/library/dd270696.aspx
  [4]: http://msdn.microsoft.com/en-us/library/dd235606.aspx
  [5]: http://blogs.msdn.com/b/pfxteam/archive/2010/04/09/9990424.aspx



Content Type	Original Author	Original Content on Stackoverflow
Question	Keith G	View Question on Stackoverflow
Solution 1 - C#	Stephen Cleary	View Answer on Stackoverflow
Solution 2 - C#	Hatch	View Answer on Stackoverflow

Task parallel library replacement for BackgroundWorker?

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

MOQ - how to mock an interface that needs to be cast to another interface?

JQuery html() vs. innerHTML

Attributions