The `Show` function shows the form in a non modal form. This means that you can click on the parent form.

`ShowDialog` shows the form modally, meaning you cannot go to the parent form

`Application.Run()` runs the main parent form, and makes that form the main form. Application.Run() is usually found in `main`.



- `Show` displays the form in a non-modal way.
- `ShowDialog` displays the form in a [modal][1] way.
- `Application.Run` starts a message loop for the application and shows the form as the application&#39;s main form


  [1]: http://en.wikipedia.org/wiki/Modal_window

Application.Run() starts the message loop for the windows forms application.  At its most basic level it keeps the process alive until the last form is closed.

http://msdn.microsoft.com/en-us/library/system.windows.forms.application.run(v=vs.110).aspx

Show() method shows a windows form in a non-modal state.

http://msdn.microsoft.com/en-us/library/szcefbbd(v=vs.110).aspx

ShowDialog() method shows a window in a modal state and stops execution of the calling context until a result is returned from the windows form open by the method.

http://msdn.microsoft.com/en-us/library/c7ykbedk(v=vs.110).aspx

How to get values from properties file using Groovy?

I require to have a property file (.properties) which would have file names as key, and their destination path as the value. I will need the key to be resolved at runtime, depending on file that needs to be moved. 

So far I am able to load the properties it seems but can&#39;t &quot;get&quot; the value from the loaded properties.

I referred to the thread : https://stackoverflow.com/questions/2055959/groovy-how-to-access-to-properties-file and following is the code snippet i have so far 

    def  props = new Properties();
	File propFile = 
              new File(&#39;D:/XX/XX_Batch/XX_BATCH_COMMON/src/main/resources/patchFiles.properties&#39;)
	props.load(propFile.newDataInputStream())
	def config = new ConfigSlurper().parse(props)
		def ant = new AntBuilder()
		def list = ant.fileScanner {
					fileset(dir:getSrcPath()) {
		            	include(name:&quot;**/*&quot;)
		            }
	    }
		for (f in list) {
		   def key = f.name
		   println(props)
		   println(config[key])
		   println(config)
		   def destn = new File(config[&#39;a&#39;])
			
		}

the properties file has the following entries for now : 

    jan-feb-mar.jsp=/XX/Test/1
    XX-1.0.0-SNAPSHOT.jar=/XX/Test/1
    a=b
    c=d
    

Correct values are returned if I look up using either props.getProperty(&#39;a&#39;)
or,
config[&#39;a&#39;]
Also tried the code: notation

But as soon as switch to using the variable &quot;key&quot;, as in config[key] it returns --&gt; [:]

I am new to groovy, can&#39;t say what am i missing here.




Get values from properties file using Groovy

I know how to repeat the last command in Vim. I use &lt;kbd&gt;.&lt;/kbd&gt;.

But how can I repeat the last macro? It&#39;s a little non-comfortable to press &lt;kbd&gt;@&lt;/kbd&gt;&lt;kbd&gt;q&lt;/kbd&gt; everytime I want to repeat it.

I tried with &lt;kbd&gt;.&lt;/kbd&gt; but it just repeats the last command from the macro.

Is there a shorter way of doing that?

How can I repeat the last VIM macro?

What&#39;s the difference between new Show(), ShowDialog() and Application.Run() functions?
In `main` (winforms) I saw :
     
    Application.Run(new Form1());

Then, for Form1, I also saw `Form1.Show()` with description: &quot;Shows the control to the user.&quot;
For ShowDialog, it said &quot;Shows the form as a modal dialog box&quot;. 

What does this mean? 

What are each of their uses and which is most common?



What&#39;s the difference between Show(), ShowDialog() and Application.Run() functions?

What's the difference between new Show(), ShowDialog() and Application.Run() functions?
In <code>main</code> (winforms) I saw :
<pre><code class="hljs language-arduino">Application.Run(new Form1());
</code></pre>
Then, for Form1, I also saw <code>Form1.Show()</code> with description: "Shows the control to the user."
For ShowDialog, it said "Shows the form as a modal dialog box".
What does this mean?
What are each of their uses and which is most common?

I am testing a method for a service that makes a Web `API` call. Using a normal `HttpClient` works fine for unit tests if I also run the web service (located in another project in the solution) locally. 

However when I check in my changes the build server won&#39;t have access to the web service so the tests will fail.

I&#39;ve devised a way around this for my unit tests by creating an `IHttpClient` interface and implementing a version that I use in my application. For unit tests, I make a mocked version complete with a mocked asynchronous post method. Here&#39;s where I have run into problems. I want to return an OK `HttpStatusResult` for this particular test. For another similar test I will be returning a bad result. 

The test will run but will never complete. It hangs at the await. I am new to asynchronous programming, delegates, and Moq itself and I&#39;ve been searching SO and google for a while learning new things but I still can&#39;t seem to get past this problem.

Here is the method I am trying to test:

    public async Task&lt;bool&gt; QueueNotificationAsync(IHttpClient client, Email email)
    {
        // do stuff
        try
        {
            // The test hangs here, never returning
            HttpResponseMessage response = await client.PostAsync(uri, content);

            // more logic here
        }
        // more stuff
    }

Here&#39;s my unit test method:

    [TestMethod]
    public async Task QueueNotificationAsync_Completes_With_ValidEmail()
    {
        Email email = new Email()
        {
            FromAddress = &quot;bob@example.com&quot;,
            ToAddress = &quot;bill@example.com&quot;,
            CCAddress = &quot;brian@example.com&quot;,
            BCCAddress = &quot;ben@example.com&quot;,
            Subject = &quot;Hello&quot;,
            Body = &quot;Hello World.&quot;
        };
        var mockClient = new Mock&lt;IHttpClient&gt;();
        mockClient.Setup(c =&gt; c.PostAsync(
            It.IsAny&lt;Uri&gt;(),
            It.IsAny&lt;HttpContent&gt;()
            )).Returns(() =&gt; new Task&lt;HttpResponseMessage&gt;(() =&gt; new HttpResponseMessage(System.Net.HttpStatusCode.OK)));

        bool result = await _notificationRequestService.QueueNotificationAsync(mockClient.Object, email);

        Assert.IsTrue(result, &quot;Queue failed.&quot;);
    }

What am I doing wrong?

Thank you for your help.

Using Moq to mock an asynchronous method for a unit test

In a library using Monitor.PulseAll() for thread synchronization, I noticed that the latency from the time PulseAll(...) is called to the time a thread is woken up seems to follow a &quot;stepping stair&quot; distribution -- with extremely large steps.  The woken threads are doing almost no work; and almost immediately go back to waiting on the monitor.  For example, on a box with 12 cores with 24 threads waiting on a Monitor (2x Xeon5680/Gulftown; 6 physical cores per processor; HT Disabled), the latency between the Pulse and a Thread waking up is as such:

![Latency using Monitor.PulseAll(); 3rd party library][1]

The first 12 threads (note we have 12 cores) take between 30 and 60 microseconds to respond.  Then we start getting very large jumps; with the plateaus around 700, 1300, 1900, and 2600 microseconds.

I was able to successfully recreate this behavior independent of the 3rd party library using the code below.  What this code does is launch a large number of threads (change the numThreads parameter) which just Wait on a Monitor, read a timestamp, log it to a ConcurrentSet, then immediately go back to Waiting.  Once a second PulseAll() wakes up all the threads.  It does this 20 times, and reports the latencies for the 10th iteration to the Console.

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Collections.Concurrent;
    using System.Diagnostics;

    namespace PulseAllTest
    {
        class Program
        {
            static long LastTimestamp;
            static long Iteration;
            static object SyncObj = new object();
            static Stopwatch s = new Stopwatch();
            static ConcurrentBag&lt;Tuple&lt;long, long&gt;&gt; IterationToTicks = new ConcurrentBag&lt;Tuple&lt;long, long&gt;&gt;();

            static void Main(string[] args)
            {
                long numThreads = 32;

                for (int i = 0; i &lt; numThreads; ++i)
                {
                    Task.Factory.StartNew(ReadLastTimestampAndPublish, TaskCreationOptions.LongRunning);
                }
            
                s.Start();
                for (int i = 0; i &lt; 20; ++i)
                {
                    lock (SyncObj)
                    {
                        ++Iteration;
                        LastTimestamp = s.Elapsed.Ticks;
                        Monitor.PulseAll(SyncObj);
                    }
                    Thread.Sleep(TimeSpan.FromSeconds(1));
                }

                Console.WriteLine(String.Join(&quot;\n&quot;,
                    from n in IterationToTicks where n.Item1 == 10 orderby n.Item2 
                        select ((decimal)n.Item2)/TimeSpan.TicksPerMillisecond));
                Console.Read();
            }

            static void ReadLastTimestampAndPublish()
            {
                while(true)
                {
                    lock(SyncObj)
                    {
                        Monitor.Wait(SyncObj);
                    }
                    IterationToTicks.Add(Tuple.Create(Iteration, s.Elapsed.Ticks - LastTimestamp));
                }
            }
        }
    }

Using the code above, here is an example of latencies on a box with 8 cores /w hyperthreading enabled (i.e. 16 cores in Task Manager) and 32 threads (*2x Xeon5550/Gainestown; 4 physical cores per processor; HT Enabled):

![Latency using Monitor.PulseAll(), sample code][2]

EDIT: To try to take NUMA out of the equation, below is a graph running the sample program with 16 threads on a Core i7-3770 (Ivy Bridge); 4 Physical Cores; HT Enabled:

![Latency using Monitor.PulseAll(), sample code, no NUMA][3]

**Can anyone explain why Monitor.PulseAll() behaves in this way?**

EDIT2:

To try and show that this behavior isn&#39;t inherent to waking up a bunch of threads at the same time, I&#39;ve replicated the behavior of the test program using Events; and instead of measuring the latency of PulseAll() I&#39;m measuring the latency of ManualResetEvent.Set().  The code is creating a number of worker threads then waiting for a ManualResetEvent.Set() event on the same ManualResetEvent object.  When the event is triggered, they take a latency measurement then immediately wait on their own individual per-thread AutoResetEvent.  Well before the next iteration (500ms before), the ManualResetEvent is Reset() and then each AutoResetEvent is Set() so the threads can go back to waiting on the shared ManualResetEvent.

I hesitated posting this because it could be a giant red hearing (I make no claims Events and Monitors behave similarly) plus it&#39;s using some absolutely terrible practices to get an Event to behave like a Monitor (I&#39;d love/hate to see what my co-workers would do if I submitted this to a code review); but I think the results are enlightening.

This test was done on the same machine as the original test; a 2xXeon5680/Gulftown; 6 cores per processor (12 cores total); Hyperthreading disabled.

![ManualResetEventLatency][4]

If it&#39;s not obvious how radically different this is than Monitor.PulseAll; here is the first graph overlaid onto the last graph:

![ManualResetEventLatency vs. Monitor Latency][5]

The code used to generate these measurements is below:

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Threading;
    using System.Threading.Tasks;
    using System.Collections.Concurrent;
    using System.Diagnostics;
    
    namespace MRETest
    {
        class Program
        {
            static long LastTimestamp;
            static long Iteration;
            static ManualResetEventSlim MRES = new ManualResetEventSlim(false);
            static List&lt;ReadLastTimestampAndPublish&gt; Publishers = 
                new List&lt;ReadLastTimestampAndPublish&gt;();
            static Stopwatch s = new Stopwatch();
            static ConcurrentBag&lt;Tuple&lt;long, long&gt;&gt; IterationToTicks = 
                new ConcurrentBag&lt;Tuple&lt;long, long&gt;&gt;();
    
            static void Main(string[] args)
            {
                long numThreads = 24;
                s.Start();
    
                for (int i = 0; i &lt; numThreads; ++i)
                {
                    AutoResetEvent ares = new AutoResetEvent(false);
                    ReadLastTimestampAndPublish spinner = new ReadLastTimestampAndPublish(
                        new AutoResetEvent(false));
                    Task.Factory.StartNew(spinner.Spin, TaskCreationOptions.LongRunning);
                    Publishers.Add(spinner);
                }
    
                for (int i = 0; i &lt; 20; ++i)
                {
                    ++Iteration;
                    LastTimestamp = s.Elapsed.Ticks;
                    MRES.Set();
                    Thread.Sleep(500);
                    MRES.Reset();
                    foreach (ReadLastTimestampAndPublish publisher in Publishers)
                    {
                        publisher.ARES.Set();
                    }
                    Thread.Sleep(500);
                }
    
                Console.WriteLine(String.Join(&quot;\n&quot;,
                    from n in IterationToTicks where n.Item1 == 10 orderby n.Item2
                        select ((decimal)n.Item2) / TimeSpan.TicksPerMillisecond));
                Console.Read();
            }
    
            class ReadLastTimestampAndPublish
            {
                public AutoResetEvent ARES { get; private set; }
    
                public ReadLastTimestampAndPublish(AutoResetEvent ares)
                {
                    this.ARES = ares;
                }
    
                public void Spin()
                {
                    while (true)
                    {
                        MRES.Wait();
                        IterationToTicks.Add(Tuple.Create(Iteration, s.Elapsed.Ticks - LastTimestamp));
                        ARES.WaitOne();
                    }
                }
            }
        }
    }


  [1]: http://i.stack.imgur.com/ppO9W.png
  [2]: http://i.stack.imgur.com/OmlLs.png
  [3]: http://i.stack.imgur.com/Ebm2k.png
  [4]: http://i.stack.imgur.com/LLrQQ.png
  [5]: http://i.stack.imgur.com/2CLG2.png

Why does Monitor.PulseAll result in a &quot;stepping stair&quot; latency pattern in signaled threads?

Does anyone know why `async` methods are not allowed to have `ref` and `out` arguments? I&#39;ve done a bit of research on it but the only thing I could find was that it has to do with the stack unrolling.













ref and out arguments in async method

On updating database in Entity Framework , Code first Migration, I am getting this error:

&gt; The ALTER TABLE statement conflicted with the FOREIGN KEY constraint &quot;FK_dbo.Clients_dbo.MedicalGroups_MedicalGroupId&quot;. The conflict occurred in database &quot;hrbc&quot;, table &quot;dbo.MedicalGroups&quot;, column &#39;Id&#39;.

This is my class:

    public partial class Client
    {
        [Key, DatabaseGenerated(DatabaseGeneratedOption.Identity)]
        public int Id { get; set; }

        public string FirstName { get; set; }
        public string LastName { get; set; }
        public int? MedicalGroupId { get; set; }
        [ForeignKey(&quot;MedicalGroupId&quot;)]
        public virtual MedicalGroups MedicalGroup { get { return _MedicalGroup; } set { _MedicalGroup = value; } }
    }

Here is my 2nd class:

    public partial class MedicalGroups
    {
        [Key]
        public int Id { get; set; }
        public string Name { get; set; }
    }

And this is my migration which I am trying to apply:

    public override void Up()
    {
        AddForeignKey(&quot;dbo.Clients&quot;, &quot;MedicalGroupId&quot;, &quot;dbo.MedicalGroups&quot;, &quot;Id&quot;);
        CreateIndex(&quot;dbo.Clients&quot;, &quot;MedicalGroupId&quot;);
    }

Entity Framework The ALTER TABLE statement conflicted with the FOREIGN KEY constraint

Has anyone come across a scenario for using `ConfigureAwait(true)`? Since `true` is the default option I cannot see when would you ever use it.

When should I use ConfigureAwait(true)?

**Problem:**

I have a text file of around **120,000** users (strings) which I would like to store in a collection and later to perform a search on that collection.

The search method will occur every time the user change the text of a `TextBox` and the result should be the strings that ***contain*** the text in `TextBox`.

I don&#39;t have to change the list, just pull the results and put them in a `ListBox`.

**What I&#39;ve tried so far:**

I tried with two different collections/containers, which I&#39;m dumping the string entries from an external text file (once, of course):

 1. `List&lt;string&gt; allUsers;`
 2. `HashSet&lt;string&gt; allUsers;`

With the following [LINQ][1] query:

`allUsers.Where(item =&gt; item.Contains(textBox_search.Text)).ToList();`

My search event (fires when user change the search text):

    private void textBox_search_TextChanged(object sender, EventArgs e)
    {
        if (textBox_search.Text.Length &gt; 2)
        {
            listBox_choices.DataSource = allUsers.Where(item =&gt; item.Contains(textBox_search.Text)).ToList();
        }
        else
        {
            listBox_choices.DataSource = null;
        }
    }

**Results:**

Both gave me a poor response time (around 1-3 seconds between each key press).

**Question:**

Where do you think my bottleneck is? The collection I&#39;ve used? The search method? Both?

How can I get better performance and more fluent functionality?

  [1]: http://en.wikipedia.org/wiki/Language_Integrated_Query


Fastest way to search in a string collection

**Intro:** There&#39;s a lot of comments out there that say &quot;WinForms doesn&#39;t auto-scale to DPI/font settings well; switch to WPF.&quot; However, I think that is based on .NET 1.1; it appears they actually did a pretty good job of implementing auto-scaling in .NET 2.0. At least based on our research and testing so far. However, if some of you out there know better, we&#39;d love to hear from you. &lt;sup&gt;(Please don&#39;t bother arguing we should switch to WPF... that&#39;s not an option right now.)&lt;/sup&gt;

### Questions:
 
 - What in WinForms does NOT auto-scale properly and therefore should be avoided?

 - What design guidelines should programmers follow when writing WinForms code such that it will auto-scale well?


### Design Guidelines we have identified so far:

 See [community wiki answer](https://stackoverflow.com/a/29766847/1730559) below.

Are any of those incorrect or inadequate? Any other guidelines we should adopt? Are there any other patterns that need to be avoided? Any other guidance on this would be very appreciated.

How to write WinForms code that auto-scales to system font and dpi settings?

I want to get the first day and last day of the month where a given date lies in. The date comes from a value in a UI field.

If I&#39;m using a time picker I could say

    var maxDay = dtpAttendance.MaxDate.Day;


But I&#39;m trying to get it from a DateTime object. So if I have this...

    DateTime dt = DateTime.today;


How to get first day and last day of the month from `dt`?


Getting the first and last day of a month, using a given DateTime object

I need to upgrade a .NET application to support a call to an API on a website that only supports TLS 1.2. From what I read, if the application is targeting 4.6 or higher then it will use TLS 1.2 by default. 

To test I created a Windows Forms app that targets 4.7. Unfortunately it errors when I don&#39;t explicitly set ServicePointManager.SecurityProtocol. Here is the code:

    HttpClient _client = new HttpClient();
    
    var msg = new StringBuilder();
    
    // If I uncomment the next line it works, but fails even with 4.7
    // ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
    
    var httpWebRequest = (HttpWebRequest)WebRequest.Create(&quot;https://sandbox.authorize.net&quot;);
    
    httpWebRequest.KeepAlive = false;
    
    try
    {
        var httpWebResponse = (HttpWebResponse) httpWebRequest.GetResponse();
    
        msg.AppendLine(&quot;The HTTP request Headers for the first request are: &quot;);
    
        foreach (var header in httpWebRequest.Headers)
        {
            msg.AppendLine(header.ToString());
        }
    
        ResponseTextBox.Text = msg.ToString();
       
    }
    catch (Exception exception)
    {
       ResponseTextBox.Text = exception.Message;
     
       if (exception.InnerException != null)
       {
           ResponseTextBox.Text += Environment.NewLine + @&quot;  -&gt;&quot; + exception.InnerException.Message;
    
           if (exception.InnerException.InnerException != null)
           {
                ResponseTextBox.Text += Environment.NewLine + @&quot;     -&gt;&quot; + exception.InnerException.InnerException.Message;
           }
       }
    }

If you uncomment out the following line:
  

    ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;

it works. This isn&#39;t a good solution since it hard codes what TLS version to use, so it wouldn&#39;t use TLS 1.3 in future.

What else do I need to do to get it work without having this line. I&#39;m testing from a Window 10 machine with 4.7 installed. 

**Update**

I tried a test with HttpClient and had the same results, I had to explicitly set SecurityProtocol. 

Code: 

    var msg = new StringBuilder();
    
    // Need to uncomment code below for TLS 1.2 to be used
    // ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12;
    
    try
    {
       var response = await _client.GetAsync(@&quot;https://sandbox.authorize.net&quot;);
    
       msg.AppendLine(&quot;response.IsSuccessStatusCode : &quot; + response.IsSuccessStatusCode);
    
       msg.AppendLine(await response.Content.ReadAsStringAsync());
    
       textBox.Text = msg.ToString();
      }
       
      catch (Exception exception)
      {
          textBox.Text = exception.Message;
    
          if (exception.InnerException != null)
          {
              textBox.Text += Environment.NewLine + @&quot;  -&gt;&quot; + exception.InnerException.Message;
          }
       }



TLS 1.2 not negotiated in .NET 4.7 without explicit ServicePointManager.SecurityProtocol call

After adding `WindowsRuntime` to a WinForms-project, building the project fails with Error &quot;Must use PackageReference&quot;. The build log is more precise:

&gt;C:\[...]\Visual Studio 2017\Projects\Projectname\packages\Microsoft.Windows.SDK.Contracts.10.0.18362.2005\build\Microsoft.Windows.SDK.Contracts.targets(4,5): error : Must use PackageReference

Here&#39;s what I did:

Install-Package Microsoft.Windows.SDK.Contracts

with references to:

 - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETCore\v4.5\System.Runtime.WindowsRuntime.dll,
 - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Facades\System.Runtime.dll
 - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Facades\System.Threading.Tasks.dll
 - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Facades\System.IO.dll
 - C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\Facades\System.Runtime.InteropServices.WindowsRuntime.dll.

Is it maybe a thing with the .NET version? In the project&#39;s packages.config there is 4.6 while the project targets 4.5.

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;packages&gt;
    &lt;package id=&quot;Microsoft.Windows.SDK.Contracts&quot; version=&quot;10.0.18362.2005&quot; targetFramework=&quot;net45&quot;/&gt;
    &lt;package id=&quot;System.Runtime.WindowsRuntime&quot; version=&quot;4.6.0&quot; targetFramework=&quot;net45&quot; /&gt;
    &lt;package id=&quot;System.Runtime.WindowsRuntime.UI.Xaml&quot; version=&quot;4.6.0&quot; targetFramework=&quot;net45&quot; /&gt;
    &lt;/packages&gt;

There are no compile errors... only this strange &quot;PackageReference&quot; error.


Content Type	Original Author	Original Content on Stackoverflow
Question	Edward Karak	View Question on Stackoverflow
Solution 1 - C#	Edward Karak	View Answer on Stackoverflow
Solution 2 - C#	Thomas Levesque	View Answer on Stackoverflow
Solution 3 - C#	Austin	View Answer on Stackoverflow

What's the difference between Show(), ShowDialog() and Application.Run() functions?

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

Solution 3 - C#

How can I repeat the last VIM macro?

Get values from properties file using Groovy

Attributions