There should be a button on the toolbar like this one that will let you select the 4 different &quot;diff modes&quot;.

![enter image description here][1]

You can also use the following keyboard shortcuts:

- `Ctrl+\`, `Ctrl 1` - Inline
- `Ctrl+\`, `Ctrl 2` - Side-by-side
- `Ctrl+\`, `Ctrl 3` - Left Only
- `Ctrl+\`, `Ctrl 4` - Right Only

to change the view.


  [1]: http://i.stack.imgur.com/nRSto.png

Below screenshot will help in setting the option to compare side by side.


  [![Side by side mode][1]][1]


  [1]: http://i.stack.imgur.com/7nqFx.jpg

I think this question will bring me instant fame here on Stack Overflow.

Suppose you have the following type:

    // represents a decimal number with at most two decimal places after the period
    struct NumberFixedPoint2
    {
        decimal number;

        // an integer has no fractional part; can convert to this type
        public static implicit operator NumberFixedPoint2(int integer)
        {
            return new NumberFixedPoint2 { number = integer };
        }
        
        // this type is a decimal number; can convert to System.Decimal
        public static implicit operator decimal(NumberFixedPoint2 nfp2)
        {
            return nfp2.number;
        }

        /* will add more nice members later */
    }

It has been written such that only safe conversions that don&#39;t lose precision are allowed. However, when I try this code:

        static void Main()
        {
            decimal bad = 2.718281828m;
            NumberFixedPoint2 badNfp2 = (NumberFixedPoint2)bad;
            Console.WriteLine(badNfp2);
        }

I am surprised this compiles and, when run, **writes out `2`**. The conversion from `int` (of value `2`) to `NumberFixedPoint2` is important here. (An overload of `WriteLine` that takes in a `System.Decimal` is preferred, in case anyone wonders.)

Why on Earth is the conversion from `decimal` to `NumberFixedPoint2` allowed? (By the way, in the above code, if `NumberFixedPoint2` is changed from a struct to a class, nothing changes.)

Do you know if the C# Language Specification says that an implicit conversion from `int` to a custom type &quot;implies&quot; the existence of a &quot;direct&quot; explicit conversion from `decimal` to that custom type?

It becomes much worse. Try this code instead:

        static void Main()
        {
            decimal? moreBad = 7.3890560989m;
            NumberFixedPoint2? moreBadNfp2 = (NumberFixedPoint2?)moreBad;
            Console.WriteLine(moreBadNfp2.Value);
        }

As you see, we have (lifted) `Nullable&lt;&gt;` conversions here. But oh yes, that does compile.

When compiled in **x86** &quot;platform&quot;, this code writes out an unpredictable numeric value. Which one varies from time to time. As an example, on one occasion I got **`2289956`**. Now, that&#39;s one serious bug!

When compiled for the **x64** platform, the above code crashes the application with a `System.InvalidProgramException` with message **Common Language Runtime detected an invalid program.** According to the documentation of the `InvalidProgramException` class:

&gt; Generally this indicates a bug in the compiler that generated the program.

Does anyone (like Eric Lippert, or someone who has worked with lifted conversions in the C# compiler) know the cause of these bugs? Like, what is a sufficient condition that we don&#39;t run into them in our code? Because the type `NumberFixedPoint2` is actually something that we have in real code (managing other people&#39;s money and stuff).

Serious bugs with lifted/nullable conversions from int, allowing conversion from decimal

What is the recommended way of generating a secure, random AES key in Java, using the standard JDK?

In other posts, I have found this, but using a `SecretKeyFactory` might be a better idea:

&lt;!-- language: java --&gt;

    KeyGenerator keyGen = KeyGenerator.getInstance(&quot;AES&quot;);
    SecureRandom random = new SecureRandom(); // cryptograph. secure random 
    keyGen.init(random); 
    SecretKey secretKey = keyGen.generateKey();

It would be great if the answer included an explanation of why it is a good way of generating the random key. Thanks!

How to create a secure random AES key in Java?

When I was doing C# code reviews at first in VS 2012 I was getting a side by side comparison of the old and new code.
However now I am getting all code in the same window with red lines for old code and green lines for new code.
I cannot find the option to change this back to a difference window.
I know this is a simple issue but any help will be greatly appreciated!

Visual Studio Code Review Difference Window

<p>When I was doing C# code reviews at first in VS 2012 I was getting a side by side comparison of the old and new code.
However now I am getting all code in the same window with red lines for old code and green lines for new code.
I cannot find the option to change this back to a difference window.
I know this is a simple issue but any help will be greatly appreciated!</p>


We are beginning to use the code review functionality built-in to VS 2012 and VS 2013 preview. Requesting the review and adding comments seem pretty straightforward. If someone adds comments requesting the code to be changed, then how does the requester make these changes and show them?

So the process would flow like this:

1. Person 1 requests a code review.
2. Person 2 adds comments and selects &quot;Needs Work.&quot;
3. Person 1 makes the necessary changes.

How does Person 1 now show these changes to Person 2? You can add comments and send them, but the files don&#39;t change. I&#39;m assuming the files are from the changeset created when the original review was requested. Should Person 1 close this review, and request a second review?

Creating a second review doesn&#39;t seem optimal, because you lose the history of your conversation of why you were making the changes.

There are ton of websites showing how to use the basic functionality of the code reviews, but are there any sites that show the best practices? For instance, who should be clicking the check boxes next to files?

TFS Code Reviews - Show updated files in response to comments

I&#39;m very new to the [ASP.NET][1] C# area. I&#39;m planning to send a mail through ASP.NET C# and this is the [SMTP][2] address from my [ISP][3]: 

    smtp-proxy.tm.net.my

Below is what I tried to do, but failed.

    &lt;%@ Page Language=&quot;C#&quot; AutoEventWireup=&quot;true&quot; CodeFile=&quot;Default.aspx.cs&quot; Inherits=&quot;SendMail&quot; %&gt;
    &lt;html&gt;
    &lt;head id=&quot;Head1&quot; runat=&quot;server&quot;&gt;&lt;title&gt;Email Test Page&lt;/title&gt;&lt;/head&gt;
    &lt;body&gt;
        &lt;form id=&quot;form1&quot; runat=&quot;server&quot;&gt;
            Message to: &lt;asp:TextBox ID=&quot;txtTo&quot; runat=&quot;server&quot; /&gt;&lt;br&gt;
            Message from: &lt;asp:TextBox ID=&quot;txtFrom&quot; runat=&quot;server&quot; /&gt;&lt;br&gt;
            Subject: &lt;asp:TextBox ID=&quot;txtSubject&quot; runat=&quot;server&quot; /&gt;&lt;br&gt;
            Message Body:&lt;br&gt;
            &lt;asp:TextBox ID=&quot;txtBody&quot; runat=&quot;server&quot; Height=&quot;171px&quot; TextMode=&quot;MultiLine&quot;  Width=&quot;270px&quot; /&gt;&lt;br&gt;
            &lt;asp:Button ID=&quot;Btn_SendMail&quot; runat=&quot;server&quot; onclick=&quot;Btn_SendMail_Click&quot; Text=&quot;Send Email&quot; /&gt;&lt;br&gt;
            &lt;asp:Label ID=&quot;Label1&quot; runat=&quot;server&quot; Text=&quot;Label&quot;&gt;&lt;/asp:Label&gt;
        &lt;/form&gt;
    &lt;/body&gt;
    &lt;/html&gt;

And below is my [code-behind][4]:

    using System;
    using System.Web.UI.WebControls;
    using System.Net.Mail;
    public partial class SendMail : System.Web.UI.Page
    {
        protected void Btn_SendMail_Click(object sender, EventArgs e)
        {
            MailMessage mailObj = new MailMessage(
                txtFrom.Text, txtTo.Text, txtSubject.Text, txtBody.Text);
            SmtpClient SMTPServer = new SmtpClient(&quot;127.0.0.1&quot;);
            try
            {
                SMTPServer.Send(mailObj);
            }
            catch (Exception ex)
            {
                Label1.Text = ex.ToString();
            }
        }
    }

PS: I&#39;m sorry that I couldn&#39;t understand the receiver/sender SMTP concept, and so I am trying to understand the whole concept from here.

  [1]: http://en.wikipedia.org/wiki/ASP.NET
  [2]: http://en.wikipedia.org/wiki/Simple_Mail_Transfer_Protocol
  [3]: http://en.wikipedia.org/wiki/Internet_service_provider
  [4]: http://en.wikipedia.org/wiki/ASP.NET#Code-behind_solutions


How to send email in ASP.NET C#

I have a DataGrid which is populating data from ViewModel by asynchronous method.My DataGrid is :
   

    &lt;DataGrid ItemsSource=&quot;{Binding MatchObsCollection}&quot;  x:Name=&quot;dataGridParent&quot; 
                          Style=&quot;{StaticResource EfesDataGridStyle}&quot; 
                          HorizontalGridLinesBrush=&quot;#DADADA&quot; VerticalGridLinesBrush=&quot;#DADADA&quot; Cursor=&quot;Hand&quot; AutoGenerateColumns=&quot;False&quot; 
                          RowDetailsVisibilityMode=&quot;Visible&quot;  &gt;

I am using http://www.amazedsaint.com/2010/10/asynchronous-delegate-command-for-your.html to implement asynchronous way in my viewmodel.

Here is my viewmodel code:

    public class MainWindowViewModel:WorkspaceViewModel,INotifyCollectionChanged
        {        
            
            MatchBLL matchBLL = new MatchBLL();
            EfesBetServiceReference.EfesBetClient proxy = new EfesBetClient();
            
            public ICommand DoSomethingCommand { get; set; }
            public MainWindowViewModel()
            {
                DoSomethingCommand = new AsyncDelegateCommand(
                    () =&gt; Load(), null, null,
                    (ex) =&gt; Debug.WriteLine(ex.Message));           
                _matchObsCollection = new ObservableCollection&lt;EfesBet.DataContract.GetMatchDetailsDC&gt;();                
                
            }       
            
            List&lt;EfesBet.DataContract.GetMatchDetailsDC&gt; matchList;
            ObservableCollection&lt;EfesBet.DataContract.GetMatchDetailsDC&gt; _matchObsCollection;
    
            public ObservableCollection&lt;EfesBet.DataContract.GetMatchDetailsDC&gt; MatchObsCollection
            {
                get { return _matchObsCollection; }
                set
                {
                    _matchObsCollection = value;
                    OnPropertyChanged(&quot;MatchObsCollection&quot;);
                }
            }        
            //
            public void Load()
            {            
                matchList = new List&lt;GetMatchDetailsDC&gt;();
                matchList = proxy.GetMatch().ToList();
    
                foreach (EfesBet.DataContract.GetMatchDetailsDC match in matchList)
                {
                    _matchObsCollection.Add(match);
                }
                
            }

As you can see in my Load() method in my ViewModel first I am getting matchList (which is a list of a DataContract Class) from my Service.Then by foreach loop I am inserting my matchList items to my _matchObsCollection(which is an ObservableCollection of DataContract Class)).Now here I am getting the above error (as I shown in Title) &quot;This type of CollectionView does not support changes to its SourceCollection from a thread different from the Dispatcher thread&quot; 
![enter image description here][1]


  [1]: http://i.stack.imgur.com/zHgtd.jpg

Can anyone suggest me any solution.Moreover if possible I would like to know how to bind my DataGrid in View and also refresh it asynchronously if any better way is there.

This type of CollectionView does not support changes to its SourceCollection from a thread different from the Dispatcher thread

 I have a class, like this:

    public class MyClass
    {
        public int Value { get; set; }
        public bool IsValid { get; set; }
    }
&lt;sub&gt;In actual fact it&#39;s much larger, but this recreates the problem (weirdness).&lt;/sub&gt;

I want to get the sum of the `Value`, where the instance is valid. So far, I&#39;ve found two solutions to this.

The first one is this:
-

    int result = myCollection.Where(mc =&gt; mc.IsValid).Select(mc =&gt; mc.Value).Sum();

The second one, however, is this:
-
    
    int result = myCollection.Select(mc =&gt; mc.IsValid ? mc.Value : 0).Sum();

I want to get the most efficient method. I, at first, thought that the second one would be more efficient. Then the theoretical part of me started going &quot;Well, one is O(n + m + m), the other one is O(n + n). The first one should perform better with more invalids, while the second one should perform better with less&quot;. I thought that they would perform equally.
EDIT: And then @Martin pointed out that the Where and the Select were combined, so it should actually be O(m + n). However, if you look below, it seems like this is not related.

---

[So I put it to the test.](https://gist.github.com/anonymous/68fc3b49478ee2848a27)
=
&lt;sub&gt;(It&#39;s 100+ lines, so I thought it was better to post it as a Gist.)&lt;/sub&gt;  
The results were... interesting.

&lt;sub&gt;With 0% tie tolerance:&lt;/sub&gt;
-
The scales are in the favour of `Select` and `Where`, by about ~30 points.

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
0  
Starting benchmarking.  
Ties: 0  
Where + Select: 65  
Select: 36  
&lt;/code&gt;

&lt;sub&gt;With 2% tie tolerance:&lt;/sub&gt;
-
It&#39;s the same, except that for some they were within 2%. I&#39;d say that&#39;s a minimum margin of error. `Select` and `Where` now have just a ~20 point lead.

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
2  
Starting benchmarking.  
Ties: 6  
Where + Select: 58  
Select: 37  
&lt;/code&gt;

&lt;sub&gt;With 5% tie tolerance:&lt;/sub&gt;
-
This is what I&#39;d say to be my maximum margin of error. It makes it a bit better for the `Select`, but not much.

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
5  
Starting benchmarking.  
Ties: 17  
Where + Select: 53  
Select: 31  
&lt;/code&gt;

&lt;sub&gt;With 10% tie tolerance:&lt;/sub&gt;
-
This is way out of my margin of error, but I&#39;m still interested in the result. Because it gives the `Select` and `Where` the twenty point lead it&#39;s had for a while now.

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
10  
Starting benchmarking.  
Ties: 36  
Where + Select: 44  
Select: 21  
&lt;/code&gt;

&lt;sub&gt;With 25% tie tolerance:&lt;/sub&gt;
-
This is way, **way** out of my margin of error, but I&#39;m still interested in the result, because the `Select` and `Where` **still** (nearly) keep their 20 point lead. It seems like it&#39;s outclassing it in a distinct few, and that&#39;s what giving it the lead.

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
25  
Starting benchmarking.  
Ties: 85  
Where + Select: 16  
Select: 0  
&lt;/code&gt;

---

Now, I&#39;m guessing that the 20 point lead came from the middle, where they&#39;re both bound to get **around** the same performance. I could try and log it, but it would be a whole load of information to take in. A graph would be better, I guess. 

So that&#39;s what I did.

![Select vs Select and Where.][1]

It shows that the `Select` line keeps steady (expected) and that the `Select + Where` line climbs up (expected). However, what puzzles me is why it doesn&#39;t meet with the `Select` at 50 or earlier: in fact I was expecting earlier than 50, as an extra enumerator had to be created for the `Select` and `Where`. I mean, this shows the 20-point lead, but it doesn&#39;t explain why. This, I guess, is the main point of my question.

Why does it behave like this? Should I trust it? If not, should I use the other one or this one?
=
---
As @KingKong mentioned in the comments, you can also use `Sum`&#39;s overload that takes a lambda. So my two options are now changed to this:

First:
-

    int result = myCollection.Where(mc =&gt; mc.IsValid).Sum(mc =&gt; mc.Value);

Second:
-
    
    int result = myCollection.Sum(mc =&gt; mc.IsValid ? mc.Value : 0);

I&#39;m going to make it a bit shorter, but:

&lt;code&gt;
How much do you want to be the disambiguation percentage?  
0  
Starting benchmarking.  
Ties: 0  
Where: 60  
Sum: 41  
How much do you want to be the disambiguation percentage?  
2  
Starting benchmarking.  
Ties: 8  
Where: 55  
Sum: 38  
How much do you want to be the disambiguation percentage?  
5  
Starting benchmarking.  
Ties: 21  
Where: 49  
Sum: 31  
How much do you want to be the disambiguation percentage?  
10  
Starting benchmarking.  
Ties: 39  
Where: 41  
Sum: 21  
How much do you want to be the disambiguation percentage?  
25  
Starting benchmarking.  
Ties: 85  
Where: 16  
Sum: 0  
&lt;/code&gt;

The twenty-point lead is still there, meaning it doesn&#39;t have to do with the `Where` and `Select` combination pointed out by @Marcin in the comments.

&lt;sub&gt;Thanks for reading through my wall of text! Also, if you&#39;re interested, [here&#39;s](https://gist.github.com/anonymous/0adf47e3c6592f592a2c) the modified version that logs the CSV that Excel takes in.&lt;/sub&gt;

  [1]: http://i.stack.imgur.com/zQhQS.png

Why are Where and Select outperforming just Select?

`[ThreadStatic]` is defined using attribute while `ThreadLocal&lt;T&gt;` uses generic. 
Why different design solutions were chosen? 
What are the advantages and disadvantages of using generic over attributes in this case?


ThreadStatic v.s. ThreadLocal&lt;T&gt;: is generic better than attribute?

We have a really big solution with more than 200 projects and thousands of files. Despite of that the solution used to load pretty quickly in Visual Studio 2010 as well as 2012. However, after copying the whole SVN repository to another location, loading and closing the solution suddenly took extreeeemly long. (I am talking about 30-60 minutes here!)

Why does it take sooo long to load my solution in Visual Studio?

I try to add a new file to my source controlled solution and receive this message:

&gt; A file or folder with the name &#39;xxx&#39; already exists. Please give a unique
&gt; name to the item you are adding, or delete the existing item first.

I&#39;m 100% sure that there is no file with the given name.

So how do I get VS to add items again?

A file or folder with the name already exists Visual Studio

What is the Visual Studio keyboard shortcut to open the Package Manager Console?

If one doesn&#39;t exist, then how can we create it? 

Keyboard Shortcut for the Visual Studio Package Manager Console?

is there a way in Visual Studio to use a custom Configuration like &quot;#if DEBUG&quot;

I need a &quot;#if OFFLINE&quot; as my Build-Config&#39;s name is &quot;Offline&quot; (only for further debug-purposes too)...

Thanks!

#if debug --&gt; #if myOwnConfig?

I&#39;ve been working on a debugger visualizer for Visual Studio for some time and while the actual visualizer works fine. The problem is that it always places itself at the top of the visualizer list when examining a variable which really annoys some of the users who rather have Text as the top one (since the top one is also default when opening VS).

![enter image description here][1]

I can&#39;t find any support for this on [DialogDebuggerVisualizer][2] or [DebuggerVisualizerAttribute][3] which were my first thoughts so I&#39;ve been scouring SO/MSDN/Google for information on how to affect the sort order of the visualizers (preferably to put mine last in the list) but to no avail. 

Below is how I register my visualizer, it then just shows a form based on the value that is being visualized. 

    using Microsoft.VisualStudio.DebuggerVisualizers;
	
	[assembly: System.Diagnostics.DebuggerVisualizer(
	    typeof(Shorthand.VSAddins.JsonVisualizer.JsonVisualizer),
	    typeof(VisualizerObjectSource),
	    Target = typeof(string),
	    Description = &quot;Json Visualizer&quot;)]
	namespace Shorthand.VSAddins.JsonVisualizer
	{
	    public class JsonVisualizer : DialogDebuggerVisualizer
	    {
	        protected override void Show(IDialogVisualizerService windowService, IVisualizerObjectProvider objectProvider)
	        {
	            var json = objectProvider.GetObject() as string;
	
	            var form = new VisualizerForm { Json = json };
	            windowService.ShowDialog(form);
	        }
	    }
	}

Does anyone know if it is possible to affect the order of the visualizers or should I just let it be?


  [1]: http://i.stack.imgur.com/OGkXn.png
  [2]: http://msdn.microsoft.com/en-us/library/microsoft.visualstudio.debuggervisualizers.dialogdebuggervisualizer.aspx
  [3]: http://msdn.microsoft.com/en-us/library/system.diagnostics.debuggervisualizerattribute.aspx

Content Type	Original Author	Original Content on Stackoverflow
Question	Paddy	View Question on Stackoverflow
Solution 1 - C#	DaveShaw	View Answer on Stackoverflow
Solution 2 - C#	Shiv	View Answer on Stackoverflow

Visual Studio Code Review Difference Window

C# Problem Overview

C# Solutions

Solution 1 - C#

Solution 2 - C#

How to create a secure random AES key in Java?

Serious bugs with lifted/nullable conversions from int, allowing conversion from decimal

Attributions