This is a new feature as of VS 2015 Update 2 [XAML Diagnostics](https://www.visualstudio.com/en-us/news/vs2015-update2-vs.aspx#misc). 
This shows up only if you are debugging the application. 

If you really need to disable this, there&#39;s an option in the Tools &gt; Options &gt; Debugging &gt; General - Enable UI Debugging Tools for XAML &gt; Show runtime tools in application

[![XAML UI runtime tools options][1]][1]


  [1]: http://i.stack.imgur.com/wpx8L.png

This is new (and, actually, useful) feature in VS 2015 Update 2 (In-App Menu).
It allows you to pick visuals directly from the screen and switch to visual tree viewer (see &quot;Live Visual Tree&quot; toolbox).  

It affects debug mode only.

As the others have said it is a UI Debugger and can be very helpful. You don&#39;t need to go to the options menu to disable this though. There is a button that toggles it on and off in the Live Visual Tree tab. 
&lt;br/&gt;
See image [UI Debugger toggle - visual studio][1]

  [1]: https://i.stack.imgur.com/b4qzF.png

I am really a newbie in this forum. But I have been playing with airflow, for sometime, for our company.  Sorry if this question sounds really dumb.

I am writing a pipeline using bunch of BashOperators. 
Basically, for each Task, I want to simply call a REST api using &#39;curl&#39; 

This is what my pipeline looks like(very simplified version):

     
    from airflow import DAG
    from airflow.operators import BashOperator, PythonOperator
    from dateutil import tz
    import datetime
    
    datetime_obj = datetime.datetime
                                      
    default_args = {
        &#39;owner&#39;: &#39;airflow&#39;,
        &#39;depends_on_past&#39;: False,
        &#39;start_date&#39;: datetime.datetime.combine(datetime_obj.today() - datetime.timedelta(1), datetime_obj.min.time()),
        &#39;email&#39;: [&#39;xxxx@xxx.xxx&#39;],
        &#39;email_on_failure&#39;: True,
        &#39;email_on_retry&#39;: False,
        &#39;retries&#39;: 2,
        &#39;retry_delay&#39;: datetime.timedelta(minutes=5),
    }
    
    
    current_datetime = datetime_obj.now(tz=tz.tzlocal())
    
    dag = DAG(
        &#39;test_run&#39;, default_args=default_args, schedule_interval=datetime.timedelta(minutes=60))
    
    curl_cmd=&#39;curl -XPOST &quot;&#39;+hostname+&#39;:8000/run?st=&#39;+current_datetime +&#39;&quot;&#39;
    
    
    t1 = BashOperator(
        task_id=&#39;rest-api-1&#39;,
        bash_command=curl_cmd,
        dag=dag)

If you notice I am doing `current_datetime= datetime_obj.now(tz=tz.tzlocal())`
Instead what I want here is ***&#39;execution_date&#39;*** 

How do I use **&#39;execution_date&#39;** directly and assign it to a variable in my python file? 

I have having this general issue of accessing args. 
Any help will be genuinely appreciated.


Thanks


execution_date in airflow: need to access as a variable

I have a Jenkinsfile with multiple stages and one of them is in fact another job (the deploy one) which can fail in some cases.

I know that I can made prompts using Jenkinsfile but I don&#39;t really know how to implement a retry mechanism for this job.

I want to be able to click on the failed stage and choose to retry it.
[![jenkins-pipelines-with-stages][1]][1] 


  [1]: http://i.stack.imgur.com/uI8vp.png

How do I implement a retry option for failed stages in Jenkins pipelines?

[![enter image description here][1]][1]


  [1]: http://i.stack.imgur.com/YUiOz.png

Hi!

I am new in wpf application development. I just create a demo application and I see that the black box appearing in the top of my application. Can anyone tell me how can I remove this ? 

I am sorry, I don&#39;t even know the name of it.

Strange black box appearing in wpf application

<a href="http://i.stack.imgur.com/YUiOz.png" target="_blank" rel="noopener noreferrer"><img src="http://i.stack.imgur.com/YUiOz.png" alt="enter image description here"></a>
Hi!
I am new in wpf application development. I just create a demo application and I see that the black box appearing in the top of my application. Can anyone tell me how can I remove this ?
I am sorry, I don't even know the name of it.

How do you add and use an SQLite database in an ASP.NET Core web application, using EntityFramework 7 ?

I dived into ASP.NET Core the moment I heard about it and created my first web application, I suddenly had a bunch of data that I wanted to store and SQLite seemed like the obvious choice.  
Since I wanted it to stay with my application, keep it lightweight, simple and avoid setting up a separate database.  

 So how would one go about creating an SQLite database in ASP.NET Core?


* ASP.NET Core - now formerly known as ASP.NET MVC 6   
* EntityFramework Core - now formerly known as EntityFramework 7

SQLite in ASP.NET Core with EntityFrameworkCore

**Is it possible to develop and build Linux applications with Xamarin with the same code base?**

After a few years with Ubuntu, my main OS right now is Windows again. But it&#39;s not impossible that I could switch to Mac.

Right now I have a bit of experience with Qt and no experience with Xamarin.
With Qt you can develop *on* Windows, Linux, and Mac and *for* Windows, Linux, Mac, iOS, Android, Windows Mobile, ... They are pretty clear about that.

Since Xamarin is free and open source now and I still don&#39;t have much experience in Qt, I&#39;m considering trying out Xamarin for cross platform development instead of Qt.

Not being able to release my software for Linux would be a deal breaker for me. Being able to develop on Linux would be nice, but is optional.
But after all my Google research, I could only find information and people asking for support to develop *on* Linux and not *for* Linux.

As far as I know, this shouldn&#39;t be a problem with Mono alone. But as far as I know Xamarin &gt; Mono and I don&#39;t get everything in Mono I could get in Xamarin.

I&#39;m also not sure how well-supported Mono will be in the future. For me it looks like Xamarin is much more important for Microsoft than Mono itself.

I&#39;m not sure if it&#39;s even possible, since Xamarin is based on Mono, but is it possible that Microsoft will at some point decide not to support Mono with .NET compatibility in the same way as Xamarin, or even cancel Mono as standalone completely?

So I&#39;m looking for one single framework for all desktop and mobile platforms I can rely on, and I want to know if Xamarin and/or Mono and and/or Xamarin + Mono could be an alternative to Qt before I go deeper into any of those solutions.

Can you develop Linux applications with Xamarin?

For .NET Core, [`AsyncLocal`](http://blog.stephencleary.com/2013/04/implicit-async-context-asynclocal.html) is the replacement for [`CallContext`](http://www.wintellect.com/devcenter/jeffreyr/logical-call-context-flowing-data-across-threads-appdomains-and-processes).  However, it is unclear how &quot;safe&quot; it is to use in ASP.NET Core.

In ASP.NET 4 (MVC 5) and earlier, the [thread-agility model of ASP.NET made `CallContext` unstable][1].  Thus in ASP.NET the only safe way to achieve the behavior of a per-request logical context, was to use HttpContext.Current.Items.  Under the covers, HttpContext.Current.Items is implemented with `CallContext`, but it is done in a way that is safe for ASP.NET.

In contrast, in the context of OWIN/Katana Web API, the thread-agility model was not an issue.  I was able to use CallContext safely, after [careful considerations of how correctly to dispose it][2].

But now I&#39;m dealing with ASP.NET Core.  I would like to use the following middleware:

    public class MultiTenancyMiddleware
    {
        private readonly RequestDelegate next;
        static int random;

        private static AsyncLocal&lt;string&gt; tenant = new AsyncLocal&lt;string&gt;();
        //This is the new form of &quot;CallContext&quot;.
        public static AsyncLocal&lt;string&gt; Tenant
        {
            get { return tenant; }
            private set { tenant = value; }
        }

        //This is the new verion of [ThreadStatic].
        public static ThreadLocal&lt;string&gt; LocalTenant;

        public MultiTenancyMiddleware(RequestDelegate next)
        {
            this.next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            //Just some garbage test value...
            Tenant.Value = context.Request.Path + random++;
            await next.Invoke(context);

            //using (LocalTenant = new AsyncLocal&lt;string&gt;()) { 
            //    Tenant.Value = context.Request.Path + random++;
            //    await next.Invoke(context);
            //}
        }
    }

So far, the above code *seems* to be working just fine.  But there is at least one red flag. In the past, it was critical to ensure that `CallContext` was treated like a resource that must be freed after each invocation. 

Now I see there is no self-evident way to &quot;clean up&quot; `AsyncLocal`.   

I included code, commented out, showing how `ThreadLocal&lt;T&gt;` works.  It is `IDisposable`, and so it has an obvious clean-up mechanism.  In contrast, the `AsyncLocal` is not `IDisposable`.  This is unnerving.  

Is this because `AsyncLocal` is not yet in release-candidate condition?  Or is this because it is truly no longer necessary to perform cleanup?

And even if `AsyncLocal` is being used properly in my above example, are there any kinds of old-school &quot;thread agility&quot; issues in ASP.NET Core that are going to make this middleware unworkable?

## Special Note

For those unfamiliar with the issues `CallContext` has within ASP.NET apps, in [this SO post, Jon Skeet][3] references an [in-depth discussion about the problem][4] (which in turn references [commentary from Scott Hanselman](http://www.hanselman.com/blog/ATaleOfTwoTechniquesTheThreadStaticAttributeAndSystemWebHttpContextCurrentItems.aspx)).  This &quot;problem&quot; is not a bug - it is just a circumstance that must be carefully accounted for.

Furthermore, I can personally attest to this unfortunate behavior.  When I build ASP.NET applications, I normally include load-tests as part of my automation test infrastructure.  It is during load tests that I can witness `CallContext` become unstable (where perhaps 2% to 4% of requests show `CallContext` being corrupted.  I have also seen cases where a Web API `GET` has stable `CallContext` behavior, but the `POST` operations are all unstable.  The only way to achieve total stability is to rely on HttpContext.Current.Items.

However, in the case of ASP.NET Core, I cannot rely on HttpContext.Items...there is no such static access point.  I&#39;m also not yet able to create load tests for the .NET Core apps I&#39;m tinkering with, which is partly why I&#39;ve not answered this question for myself.  :)

&gt; Again: Please understand that the &quot;instability&quot; and &quot;problem&quot; I&#39;m discussing is not a bug at all.  CallContext is not somehow flawed.  The issue is simply a consequence of the thread dispatch model employed by ASP.NET.  The solution is simply to know the issue exists, and to code accordingly (e.g. use `HttpContext.Current.Items` instead of `CallContext`, when inside an ASP.NET app).

My goal with this question is to understand how this dynamic applies (or does not) in ASP.NET Core, so that I don&#39;t accidentally build unstable code when using the new `AsyncLocal` construct.

  [1]: http://piers7.blogspot.no/2005/11/threadstatic-callcontext-and_02.html
  [2]: https://stackoverflow.com/questions/29001266/cleaning-up-callcontext-in-tpl
  [3]: https://stackoverflow.com/questions/273301/callcontext-vs-threadstatic
  [4]: http://piers7.blogspot.com/2005/11/threadstatic-callcontext-and_02.html

Safety of AsyncLocal in ASP.NET Core

I&#39;m working on a project for iOS and I&#39;m doing the programming with Visual Studios and it connects to a mac server using Xamarin. I recently tried to add more views to the storyboard and an additional class. When I tried to build the code, I received this error. http://pastebin.com/Ub5s89aa This is what the output from the console. http://pastebin.com/fhWDy2cJ

I don&#39;t know what this error means and when I tried to look up any part of the error, nothing helped. I cleaned my builded and tried to rebuild, and I also closed Visual Studios and reopen it to see if that help, but it didn&#39;t. Has anyone else had this problem before?

Failed to find or create execution context for description &lt;IBCocoaTouchPlatformToolDescription: 0x7fa8bad9a6f0&gt;

I have a collection of 1000 input message to process. I&#39;m looping the input collection and starting the new task for each message to get processed.

    //Assume this messages collection contains 1000 items
    var messages = new List&lt;string&gt;();
    
    foreach (var msg in messages)
    {
       Task.Factory.StartNew(() =&gt;
       {
        Process(msg);
       });
     }

Can we guess how many maximum messages simultaneously get processed at the time (assuming normal Quad core processor), or can we limit the maximum number of messages to be processed at the time? 

How to ensure this message get processed in the same sequence/order of the Collection?

How to limit the Maximum number of parallel tasks in c#

When I debug my application in Microsoft Visual Studio 2015 Update 2, and I open a custom wpf dialog I get some extra debugging options in a black square. See image blow.

[![enter image description here][1]][1]

How do I disable that?


This first icon says &quot;Go To Live Visual Tree&quot;.
The second icon says &quot;Enable Selection&quot;.
The third icon says &quot;Display Layout Adorners&quot;.

  [1]: http://i.stack.imgur.com/oCIqo.png

Disable Visual Studio 2015 extra debug option

My solution (which contains a dozen projects) works perfectly in Visual Studio 2013. 

In Visual Studio 2017, I can open the solution and compile it. 

But if I start the debug, I systematically get this error message: 

&gt; The security debugging option is set but it requires the Visual Studio 
    hosting process which is unavailable in this debugging configuration.The 
    security debugging option will be disabled. This option may be re-enabled in
    the Security property page. The debugging session will continue without 
    security debugging

[![enter image description here][1]][1]

And then, nothing happens. Nothing starts. 

For information, this is a solution with multiple startup projects (including a WPF project).

**Edit :**
By disabling the option &quot;Enable ClickOnce security settings&quot; under Project -&gt; Properties -&gt; Security tab, it works.


  [1]: https://i.stack.imgur.com/iWR6l.png

VS 2017 : The security debugging option is set but it requires the Visual Studio hosting process which is unavailable

Microsoft announced .NET Core 3 comes with WPF and Windows Forms. So can I create a desktop application for Linux or Mac using .NET Core 3?

Can WPF applications be run in Linux or Mac with .Net Core 3?

What is the prefered way for persisting user settings for WPF applications with .NET 5, .NET 6 or .Net Core &gt;=3.0?

Created WPF .Net Core 3.0 Project (VS2019 V16.3.1)
Now I have seen there is no Properties.Settings section anymore. 

[![SolutionExplorer][1]][1]

After online search, started to dive into Microsoft.Extensions.Configuration. 

Beside the bloated code to access the settings, now even worse -&gt; No save?&lt;br&gt;
https://stackoverflow.com/q/51351464/3090544

&gt; Fortunately or unfortunately the Microsoft.Extensions.Configuration
&gt; does not support saving by design. Read more in this Github issue [Why
&gt; there is no save in ConfigurationProvider?][2]

&lt;br&gt;
What is the prefered (and easy/fast/simple) way for persisting user settings for WPF applications with .Net Core &gt;=3.0?

&lt;br&gt;
Before `&lt;= .Net 4.8` it was as easy as: 
&lt;br&gt;

 - add the variables to the Properties. 
[![User Settings][3]][3]
&lt;br&gt;&lt;br&gt;

 - Read the variables at startup&lt;br&gt;
`var culture = new CultureInfo(Properties.Settings.Default.LanguageSettings);`
&lt;br&gt;&lt;br&gt;

 - when a variable changes -&gt; immediately save it&lt;br&gt;
   `Properties.Settings.Default.LanguageSettings = selected.TwoLetterISOLanguageName;
    Properties.Settings.Default.Save();`


  [1]: https://i.stack.imgur.com/bTION.png
  [2]: https://github.com/aspnet/Configuration/issues/385
  [3]: https://i.stack.imgur.com/J3C8Y.png

Equivalent to UserSettings / ApplicationSettings in WPF .NET 5, .NET 6 or .Net Core

I am using a custom ProgressBar. Now while a task is going on, I am showing the progress bar, but user can still interact with the views and controls. 
How do I disable the user interaction on whole view just like a ProgressDialog does , when it is visible.

Do I need to use a transparent view on top of main view and show the progress bar on that view and hide that view once a task is completed. 

Or just get the id of my parentView and set it disabled ? But then I won&#39;t be able to dim the background, just like what happens when a dialog appears on the view/Activity/Fragment. Right? 

I just want to know the way to disallow the user from any interaction while the progressbar is visible.

Thanks

How to disable user interaction while ProgressBar is visible in android?

So recently, with Android Studio 2.2 there&#39;s a new ConstraintLayout that makes designing a lot easier, but unlike `RelativeLayout` and `Linearlayout`, I can&#39;t use a `ScrollView` to surround `ConstraintLayout`. Is this possible? If so, how?  

i.e.  

    &lt;ScrollView xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
            xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
            xmlns:tools=&quot;http://schemas.android.com/tools&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;match_parent&quot;
            tools:layout_editor_absoluteX=&quot;0dp&quot;
            tools:layout_editor_absoluteY=&quot;0dp&quot;&gt;
            
            &lt;android.support.constraint.ConstraintLayout
                android:id=&quot;@+id/constraintLayout&quot;
                android:layout_width=&quot;match_parent&quot;
                android:layout_height=&quot;match_parent&quot;
                tools:layout_editor_absoluteX=&quot;0dp&quot;
                tools:layout_editor_absoluteY=&quot;0dp&quot;&gt;
                
                &lt;!-- Have whatever children you want inside --&gt;
                
            &lt;/android.support.constraint.ConstraintLayout&gt;
            
    &lt;/ScrollView&gt;

Is it possible to put a ConstraintLayout inside a ScrollView?

In the Android M we have ability to make status bar icons dark. To do that we can specify attribute in the theme&#39;s xml:

    &lt;item name=&quot;android:windowLightStatusBar&quot;&gt;true&lt;/item&gt;

OR we cat set it at runtime with this code:

    View someView = findViewById(R.id.some_view);
    if (Build.VERSION.SDK_INT &gt;= Build.VERSION_CODES.M) {
        someView.setSystemUiVisibility(someView.getSystemUiVisibility() | View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);
    }

And it actually works fine. But question is how to properly set a status bar mode to dark at runtime?

I already tried these variants:

    // Makes status bar mode dark, but also hides it along with all navigation views. 
    someView.setSystemUiVisibility(someView.getSystemUiVisibility() | ~View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);

    // Does nothing 
    someView.setSystemUiVisibility(someView.getSystemUiVisibility() &amp; ~View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);

    // Also does nothing 
    someView.setSystemUiVisibility(someView.getSystemUiVisibility() ^ View.SYSTEM_UI_FLAG_LIGHT_STATUS_BAR);

So how it can be done the right way?

Android M Light and Dark status bar programmatically - how to make it dark again?

Why colspan attribute doesn&#39;t have effect in React? I created simple component which renders the following:

    &lt;table border=&quot;1&quot;&gt;
      &lt;tr&gt;
        &lt;th colspan=&quot;2&quot;&gt;people are...&lt;/th&gt;
      &lt;/tr&gt;
      &lt;tr&gt;
        &lt;td&gt;monkeys&lt;/td&gt;
        &lt;td&gt;donkeys&lt;/td&gt;
      &lt;/tr&gt;
    &lt;/table&gt;

and what I get is:

[![enter image description here][1]][1]


  [1]: http://i.stack.imgur.com/6zZ5I.jpg

Am I missing something?

**Edit: SOLVED**

Here is the solution. React expects the attribute name as *colSpan*, not colspan. Figured this out after wasting ridiculous amount of time to discover this little evil fact.

React colspan not working

Lets say we have a simple example as below.

    &lt;input id=&quot;filter&quot; type=&quot;text&quot; /&gt;
    &lt;script&gt;

        function reload() {
		 // get data via ajax
	    }

        $(&#39;#filter&#39;).change($.debounce(250,reload));
    &lt;/script&gt;

What we&#39;re doing is introducing a small delay so that we reduce the number of calls to `reload` whilst the user is typing text into the input. 

Now, I realise that this will depend on a case by case basis but is there an accepted wisdom of how long the debounce delay should be, given an average (or maybe that should be lowest common denominator) typing/interaction speed. I generally just play around with the value until it &quot;feels&quot; right, but I may not represent a typical user. Has anyone done any studies on this? 

Content Type	Original Author	Original Content on Stackoverflow
Question	Iftieaq	View Question on Stackoverflow
Solution 1 - C#	Petr Vávro	View Answer on Stackoverflow
Solution 2 - C#	Dennis	View Answer on Stackoverflow
Solution 3 - C#	Aech	View Answer on Stackoverflow

Strange black box appearing in wpf application

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

How do I implement a retry option for failed stages in Jenkins pipelines?

execution_date in airflow: need to access as a variable

Attributions