Compare two files in Visual Studio

There are now 3 main options available to compare two files with Visual Studio:

I) Visual Studio 17.7.0 Preview 5 (and later)

Since Version 17.7.0 Preview 5.0 of Visual Studio, you can compare files using the context menu in the Solution Explorer.

Example:

1. Either you select one file and then select a second file via "Compare with..." in the context menu (left side of the screenshot)

2. Or you select two files and then use "compare selected" in the context menu (right side of the screenshot)

(The 3rd option - mark it as "select for compare" also exists, but I doubt you would use it very often)

This is a great improvement!

However, in case you want to trigger file compare from outside of Visual Studio (drag & drop or via Windows file explorer's context menu), you can read the original answer I posted (below), which is now an alternative option you have (or the only option, if you're using older versions of Visual Studio).

Inspired by Vladimir Reshetnikov's answer above, I found a very comfortable way how you can instantly compare two files with Visual Studio by using drag and drop or via the "Send To" context menu. It only requires a little preparation which you need to do once and then it is useful like a Swiss army knife.

Visual Studio already has everything you need, and there are only some configuration steps required to make this working:

II) File compare using drag & drop

Preparation:

1. Create a new batch file using your favorite text editor. Type the following:

   @echo off
   setlocal
   set vspath=C:\Program Files\Microsoft Visual Studio\2022\Enterprise\Common7\IDE
   start "Compare files" /B /MIN "%vspath%\devenv.exe" /diff %2 %1 First:'%2' Second:'%1'
   

   You might notice that I have reversed the %1 and %2 parameters in the batch. This is because I noticed that the file explorer passes the second file as the first parameter, and then the first file as the second parameter.

2. Save this code as VS_FileCompare.cmd to use it, and modify vspath if required to match the location of devenv.exe (depending on the Visual Studio version you're currently using, see footnote^*) )

3. Either create a shortcut named "File Compare" for VS_FileCompare.cmd and place it on the desktop (as used in the animation below), so it is always available to drag & drop files onto it or directly place the batch file on the desktop. That's all!

Usage:

1. Open the Windows explorer via Win + E

2. Select two files to compare in the explorer

3. Drag and drop them as shown in the animation below:

   

4. After a few seconds (depending on the launch time of Visual Studio), the results will be shown in Visual Studio:

   

Note: It does not harm if Visual Studio is already open. In this case it will just open up a new window within the running instance of Visual Studio. So you can compare multiple file pairs, but please ensure you have selected only two files at a time.

III) Alternative way: SendTo context menu

Here's an alternative how you can use the batch file VS_FileCompare.cmd mentioned in the section above. It allows to use the context menu's Send To folder to compare the files.

Preparation:

1. Create a shortcut "Compare2Files VS" for the batch file VS_FileCompare.cmd and copy it into the SendTo folder. Open the Windows explorer via Win + E
2. Open the SendTo folder by entering shell:sendto into the file explorer's address bar (as described here). Then, put the prepared shortcut into this folder.

Usage:

1. Open the Windows explorer via Win + E

2. Select two files to compare in the explorer

3. Assuming the shortcut for the batch file VS_FileCompare.cmd is named "Compare2Files VS", you can select the two files, right-click and select Send To → Compare2Files VS to invoke the compare as shown below:

   

4. After a few seconds (depending on the launch time of Visual Studio), the results will be shown in Visual Studio:

   

HINT: If you like the SendTo folder approach, there is more you can do - for example you can open a command shell directly via SendTo and it starts with the right path (the path where the selected file resides). Look here to find out how to do that. You can even combine it with the script to gain elevated rights, with only a little extra effort.

MSDN References:

• Usage of the diff window
• Visual Studio's Diff parameter

^*) Footnote: Because vsPath (the path to DEVENV.exe) differs depending on your version of Visual Studio, I am describing how you can find it out (Windows 10):

1. In the Windows start menu , locate the Visual Studio icon

2. Right-click to bring up the context menu. Select More → Open File Location.
   Windows Explorer opens with the Visual Studio shortcut highlighted.

3. Right-Click on the Visual Studio and select Properties

4. In the properties dialog, you can find the path in "Target:"

   

^{Animations created with Screen to gif}

You can try the VSCommands extension from Visual Studio Gallery.

The latest release allows you to select two files and compare them:

(Command Window) (Ctrl + Alt + A):

Tools.DiffFiles File1 File2

Visual Studio extension: File Differ by Mads Kristensen

I have always been a fan of WinMerge which is an open source project. You can plug it into Visual Studio fairly easily.

http://blog.paulbouwer.com/2010/01/31/replace-diffmerge-tool-in-visual-studio-team-system-with-winmerge/

will show you how to do this

There is also a Visual Studio extension called CompareFiles, which does nothing else but adding the "Compare Files" entry to the Solution Explorer context menu. It invokes the built-in Visual Studio diff tool.

Just in case that someone (like me) doesn't want to install an all-in-one extension like VSCommands...

For Visual Studio 2019, the File Differ plugin allows to compare files in distinct projects:

You can install it from here:

OLD:

In Visual Studio 2012, 2013, 2015, you can also do it with Web Essentials. Just right click the files and from the context menu → Web Essential → Diff selected files:

It's also available as a separate extension.

If you have Visual Studio installed, you could also call

"%VS110COMNTOOLS%..\IDE\vsdiffmerge.exe" "File1" "File2"

or for Visual Studio 2013:

"%VS120COMNTOOLS%..\IDE\vsdiffmerge.exe" "File1" "File2"

Source: Use Visual Studio as your Diff and Merging Tool for local files

In Visual Studio, the diff can be called using the Command Window and then the Tools.DiffFiles command

1. Open the Command Window by hotkeys Ctrl + W, A or by menu View → Other Windows → Command Window
2. Enter command Tools.DiffFiles "FirstFile.cs" "SecondFile.cs"

I had this problem as well. No TFS, but I found the article Associate a file type with a file-comparison tool helpful.

Specifically, step 1b.

Open a Visual Studio command prompt and navigate to the Common7/IDE folder and type

tf diff /configure

When using Visual Studio with a localized language, the commands you write in the CommandWindow must be also localized. For example, my VS2019 is in portuguese so, i have to write this command:

Ferramentas.CompararArquivos

You can show the CommandWindow (Janela de Comando in my case) through the menu View > Other Windows > Command Window or, in my case Exibir > Outras Janelas > Janela de Comando

With Visual Studio 2022 17.7 Preview 1, a new Compare Files option has been added to Solution Explorer.

In response to this highly upvoted ticket in Developer Community, you can now compare files in Solution Explorer

Right click on a file in solution explorer, and select "Select for Compare". Then, right click on the file you wish to compare to and select "Compare with {fileName}":

This will open up the a diff comparison tab like so:

To compare any two files and merge it to one file, here are the following steps you can follow if you have Visual Studio (any version) installed.

Step 1: Open the Visual Studio command prompt. If you do not find the Visual Studio command prompt then choose Visual Studio tools

Start → Visual Studio command prompt

Step 2: Enter the command vsdiffmerge.exe

Ignore the switch /m if you need just comparison.

Syntax 1:

vsdiffmerge <file1> <file2> <file1> <outputfile> /t /m

Syntax 2:

vsdiffmerge <basefilename> <CompareFilename> <basefilename> <OutputFilename> /t /m

Example 1:

vsdiffmerge test1.js test2.js test1.js output.js /t /m

Example 2:

vsdiffmerge.exe "C:\Users\livingston\Downloads\wa\wa\Files\pre\Test.js" "C:\Users\livingston\Downloads\wa\wa\Files\Prod\Test.js" "C:\Users\livingston\Downloads\wa\wa\Files\pre\Test.js" "C:\Users\livingston\Downloads\wa\wa\Files\output\samp.js" /t /m

Step 3: Merge the files

Please note that if file name does not exist in the location, it will not open the comparer.

Also you can beautify the file before you do the comparison. In Visual Studio, Ctrl + K + D.

There are a lot of beautifier sites available online.

An excellent lightweight tool that gets the job done is the File Comparer Visual Studio extension by Akhil Mittal.

If trying to compare a file that is not in the Solution Explorer, for example you have extracted a file from some other git branch to a temporary folder, you can open the external file in some editor, highlight all and copy. Then go into your project and find the same file in Solution Explorer.
Paste in the external files contents. Then have git compare current to unmodified. Then Ctrl-Z and undo the paste when done looking at the diff.