Develop Reference

Roslyn Document of a Project return null

string sln = path;
MSBuildWorkspace workspace = MSBuildWorkspace.Create();
Solution solution = workspace.OpenSolutionAsync(sln).Result;
foreach (Project pro in solution.Projects)
{
foreach (Document documents in pro.Documents)
{
SyntaxNode rootNode = documents.GetSyntaxRootAsync().Result;
SemanticModel semanticModel = documents.GetSemanticModelAsync().Result;
IEnumerable<ClassDeclarationSyntax> myClasses = rootNode.DescendantNodes().OfType<ClassDeclarationSyntax>();
string pfad = documents.FilePath; .....
What I want to do is load a solution and its projects and the documents inside those projects then I want to get the path of those files. First 2 work but there are no documents being loaded. When executing this code, the second foreach is just being skipped completely. Debugging shows that documents is null.
I've seen other projects use this type of code but it doesn't work and I have no reason why. The dots mean there is more code but that part does actually work so I just cut it out. If someone has a clue, can you please add on to my code? Much appreciated!

The possible reasons for pro.Documents returning null could be because of:
.NET standard project is not supported by MSBuild Workspace. For more information, click here.
Missing Nuget Packages
           a. Microsoft.Build
           b. Microsoft.Build.Utilities.Core
If none of the above solutions worked, then you can try debugging yourself by using MSBuildWorkspace.WorkspaceFailed event handler. Make sure that you subscribe to this event before calling OpenSolutionAsync method. Credits: Jason Malinowski

Running FxCop analyzers from command line

I'm trying to use the new FxCop analyzers, but they're only available as NuGet packages or as VSIX extensions. I'd like to be able to run them directly, either from inside a C# program or from the command line. Anyone have any advice? Even general info on where you can find the executables for NuGet or VSIX would help.
(I know about fxcopcmd.exe, but that's the legacy version, and it works only on built .exes or .dlls. If at all possible, I need something that works before building.)

Answering my own question in case anyone else has to deal with this. I found a solution, but fair warning, it's not pretty.
I took an example C# solution from Github, loaded it up in Visual Studio, and used NuGet to install the FxCop analyzers. This installed the analyzers, and changed the solution's .csproj files to reference them. In my case, I found a copy of the analyzers in C:\users\myname.nuget\packages.
I compared the modified .csproj files to the originals, to see what changes had been made during installation. I recommend anyone following along make this comparison themselves, but in my case, the changes were:
Five Import elements at the top referencing various .props files.
An empty NuGetPackageImportStamp element.
Two new ItemGroups near the bottom, the first containing a single element named "None", the second containing various Analyzer elements referencing .dlls.
A new Target to ensure that the .props files actually existed.
I wrote a C# program that took an arbitrary solution, found all the .csproj files inside, and manually added those new XML elements to them. I skipped the one-element ItemGroup and the Target without any problems.
Ideally you would then (from inside the same C# program) call msbuild on the .sln file, save every output line matching the regex "): warning CA\d\d\d\d: " (i.e. the warnings that FxCop generated), and restore the original .csproj files. I did that all manually. Here's the code for the XML manipulation, though:
static void addAnalyzersToCsProj(string file)
{
string[] packages = new string[]
{
#"C:\users\myname\.nuget\packages\microsoft.codeanalysis.fxcopanalyzers\3.0.0\build\Microsoft.CodeAnalysis.FxCopAnalyzers.props",
#"C:\users\myname\.nuget\packages\microsoft.codeanalysis.versioncheckanalyzer\3.0.0\build\Microsoft.CodeAnalysis.VersionCheckAnalyzer.props",
#"C:\users\myname\.nuget\packages\microsoft.codequality.analyzers\3.0.0\build\Microsoft.CodeQuality.Analyzers.props",
#"C:\users\myname\.nuget\packages\microsoft.netcore.analyzers\3.0.0\build\Microsoft.NetCore.Analyzers.props",
#"C:\users\myname\.nuget\packages\microsoft.netframework.analyzers\3.0.0\build\Microsoft.NetFramework.Analyzers.props",
};
var root = XElement.Load(file);
var ns = "";
for (var i = 0; i < 5; i++)
{
XElement packageImport = new XElement(ns+"Import");
packageImport.SetAttributeValue("Project", packages[i]);
string condition = "Exists('" + packages[i] + "')";
packageImport.SetAttributeValue("Condition", condition);
root.AddFirst(packageImport);
}
var propertyGroup = root.Descendants(ns + "PropertyGroup").First();
var stamp = new XElement(ns+"NuGetPackageImportStamp", "");
propertyGroup.Elements().Last().AddAfterSelf(stamp);
var newGroup = new XElement(ns+"ItemGroup");
// do we need to include the "None Include="packages.config"" thing?
string[] libraries = new string[]
{
#"C:\users\myname\.nuget\packages\microsoft.codeanalysis.versioncheckanalyzer\3.0.0\analyzers\dotnet\cs\Microsoft.CodeAnalysis.VersionCheckAnalyzer.resources.dll",
#"C:\users\myname\.nuget\packages\microsoft.codeanalysis.versioncheckanalyzer\3.0.0\analyzers\dotnet\Microsoft.CodeAnalysis.VersionCheckAnalyzer.dll",
#"C:\users\myname\.nuget\packages\microsoft.codequality.analyzers\3.0.0\analyzers\dotnet\cs\Humanizer.dll",
#"C:\users\myname\.nuget\packages\microsoft.codequality.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.CodeQuality.Analyzers.dll",
#"C:\users\myname\.nuget\packages\microsoft.codequality.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.CodeQuality.CSharp.Analyzers.dll",
#"C:\users\myname\.nuget\packages\microsoft.netcore.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.NetCore.Analyzers.dll",
#"C:\users\myname\.nuget\packages\microsoft.netcore.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.NetCore.CSharp.Analyzers.dll",
#"C:\users\myname\.nuget\packages\microsoft.netframework.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.NetFramework.Analyzers.dll",
#"C:\users\myname\.nuget\packages\microsoft.netframework.analyzers\3.0.0\analyzers\dotnet\cs\Microsoft.NetFramework.CSharp.Analyzers.dll",
};
foreach (string lib in libraries)
{
XElement analyzer = new XElement(ns+"Analyzer");
analyzer.SetAttributeValue("Include", lib);
newGroup.AddFirst(analyzer);
}
Console.WriteLine(root.Elements().Last().ToString());
root.Elements().Last().AddAfterSelf(newGroup);
root.Save(file, SaveOptions.None);
// and do we need to include the error checking target?
}
As far as I can tell, it works, though I have no idea what would happen if you tried to do it on a solution that already has the analyzers installed normally.
Running the FxCop analyzers through msbuild seems inefficient, but I haven't found a better way to do it. They look like they're built to only work within a compiler. I hope I'm wrong, and I would still appreciate any advice on how to run the analyzers automatically without having to build the whole project.

Assemblies refer to the same metadata but only one is a linked reference; consider removing one of the references

I am currently dealing with the error word for word:
Assemblies 'C:\Users\Jake\Desktop\AudioFileSorter\AudioFileSorter\obj\Debug\Interop.QTOControlLib.dll' and 'C:\Users\Jake\Desktop\AudioFileSorter\AudioFileSorter\libs\Interop.QTOControlLib.dll' refer to the same metadata but only one is a linked reference (specified using /link option); consider removing one of the references.
My references include several files:
AxInterop.QTOControlLib.dll
Interop.QTOControlLib.dll
Interop.QTOLibrary.dll
Interop.Shell32.dll
taglib-sharp.dll
These files are all located and referenced from a folder called libs within the base location for my project: AudioFileSorter\AudioFileSorter\libs\
An additional control reference was included as the Apple QuickTime Control 2.0 from the COM references. With the exception of this reference all other references were added by right clicking 'References' in the Solution Explorer and clicking 'Add Reference' and then browsing the libs folder to pull dll file.
Obviously, I have no idea what I am doing and I don't know how to solve it. The project worked fine yesterday and after trying to build the project to a release build everything got messed up and now I have this error. I have tried removing one of the duplicate references but then i end up just missing the reference when the app calls it during this code line:
private void SortM4PFiles(string[] files)
{
WriteLine("Begin compiling .m4p files...");
foreach (string file in files)
{
axQTControl1.URL = file;
// Create new movie object
QTOLibrary.QTMovie mov = new QTOLibrary.QTMovie();
mov = axQTControl1.Movie;
string title = mov.Annotation[(int)QTAnnotationsEnum.qtAnnotationFullName];
string artist = mov.Annotation[(int)QTAnnotationsEnum.qtAnnotationArtist];
string album = mov.Annotation[(int)QTAnnotationsEnum.qtAnnotationAlbum];
songs.Add(new Song(title, album, artist, file));
songs[songs.Count - 1].setType(".m4p");
WriteLine("Evaluated " + title);
}
// Make sure the previous .m4p is not in use
// This will prevent an IOException when the file is in use and cannot be moved
axQTControl1.URL = "";
}
Any help or explanation would be greatly appreciated. Thank you.
This was the tutorial for using the QuickTime control and reading m4p and m4a metadata.

I was trying to convert one project from packages.config to PackageReference... & I got this issue. After looking into it, I realized that, there are two references added for the same dll.
How? One from nuget & one from local COM dll. I had remove one reference to fix the issue.

Checking Visual Studio projects for consistency

You have a large Visual Studio Solution with dozens of project files in it. How would you verify that all the projects follow certain rules in their property settings, and enforce these rules if a new project is added. For example check that all projects have:
TargetFrameworkVersion = "v4.5"
Platform = "AnyCPU"
WarningLevel = 4
TreatWarningsAsErrors = true
OutputPath = $(SolutionDir)bin
SignAssembly = true
AssemblyName = $(ProjectFolderName)
I know two methods myself that I will add in an answer below, but I was wondering how people go about doing this type of project test. I'm especially interested to learn about available solutions such as libraries or build tasks for this rather than having to have to invent something new or write it from scratch.

*.sln files are plain text and easily parsable, and *.*proj files are xml.
You can add a dummy project with a prebuild step that parses the sln to retrieve all of the project files, validate their settings, print a report, and fail the build if necessary.
Also, you should check this post to ensure the prebuild step is always executed. Essentially, you specify a blank output in the custom build step to force a rebuild.

The following list identifies the key file types that are automatically added to VSS when a solution is added to source control by using the Visual Studio .NET integrated development environment (IDE):
Solution files (.sln). The key items maintained within these files include a list of constituent projects, dependency information, build configuration details, and source control provider details.
Project files (.csproj or *.vbproj). The key items maintained within these files include assembly build settings, referenced assemblies (by name and path), and a file inventory.
Application configuration files. These are configuration files based on Extensible Markup Language (XML) used to control various aspects of your project's run time behavior.
Use a Single Solution Model Whenever Possible an
Also see : https://msdn.microsoft.com/en-us/library/ee817677.aspx,
https://msdn.microsoft.com/en-us/library/ee817675.aspx
AND For CONTINUOUS INTEGRATION :
there are many tools available like MSBuild, Jenkins, Apache's Continuum, Cruise Control (CC), and Hudson(plugin can be extended to c#)

This is what I have myself:
One way to do this is to create an MSBuild target with error conditions:
<Error Condition="'$(TreatWarningsAsErrors)'!='true'" Text="Invalid project setting" />
I like this approach because it is integrated with MSBuild and gives you early errors, however, you have to modify every project to import it in them or get all your team members to use a special command prompt with environment variables that will inject custom pre-build steps into your projects during the build, which is a pain.
The second approach I know is to use some library like VSUnitTest which provides an API to project properties that you can test against. VSUnitTest is currently not open source and unlisted from the NuGet service.

You could write some code to open the the solution as a text file to identify all of the csproj files referenced, in turn opening each of these as xml files, and then writing unit tests to ensure specific nodes of the project match what you expect.
It's a quick and dirty solution, but works for CI and gives you the flexibility to ignore nodes you don't care about. It actually sounds kinda useful. I have a solution with 35 projects I'd like to scan too.

Let's try something completely different: you could ensure that they are consistent by construction by generating them from a template or by using a build generation tool such as CMake. This might be simpler than attempting to make them consistent after the fact.

In our work we use a powershell script that checks project settings and modified them if they are incorrect. For example, we remove Debug configuration this way, disable C++ optimization and SSE2 support. We run it manually, but definitely it is possible to run it automatically, e.g. as pre\post build step.
Below the example:
`function Prepare-Solution {
param (
[string]$SolutionFolder
)
$files = gci -Recurse -Path $SolutionFolder -file *.vcxproj | select - ExpandProperty fullname
$files | %{
$file = $_
[xml]$xml = get-content $file
#Deleting Debug configurations...
$xml.Project.ItemGroup.ProjectConfiguration | ?{$_.Configuration -eq "Debug"} | %{$_.ParentNode.RemoveChild($_)} | Out-Null
$xml.SelectNodes("//*[contains(#Condition,'Debug')]") |%{$_.ParentNode.RemoveChild($_)} | Out-Null
if($xml.Project.ItemDefinitionGroup.ClCompile) {
$xml.Project.ItemDefinitionGroup.ClCompile | %{
#Disable SSE2
if (-not($_.EnableEnhancedInstructionSet)){
$_.AppendChild($xml.CreateElement("EnableEnhancedInstructionSet", $xml.DocumentElement.NamespaceURI)) | Out-Null
}
if($_.ParentNode.Condition.Contains("Win32")){
$_.EnableEnhancedInstructionSet = "StreamingSIMDExtensions"
}
elseif($_.ParentNode.Condition.Contains("x64")) {
$_.EnableEnhancedInstructionSet = "NotSet"
} else {
Write-Host "Neither x86 nor x64 config. Very strange!!"
}
#Disable Optimization
if (-not($_.Optimization)){
$_.AppendChild($xml.CreateElement("Optimization", $xml.DocumentElement.NamespaceURI)) | Out-Null
}
$_.Optimization = "Disabled"
}
}
$xml.Save($file);
} }`

A file is an assembly if and only if it is managed, and contains an assembly entry in its metadata. For more information on assemblies and metadata, see the topic Assembly Manifest.
How to manually determine if a file is an assembly
Start the Ildasm.exe (IL Disassembler).
Load the file you wish to test.
If ILDASM reports that the file is not a portable executable (PE) file, then it is not an assembly. For more information, see the topic How to: View Assembly Contents.
How to programmatically determine if a file is an assembly
Call the GetAssemblyName method, passing the full file path and name of the file you are testing.
If a BadImageFormatException exception is thrown, the file is not an assembly.
This example tests a DLL to see if it is an assembly.
class TestAssembly
{
static void Main()
{
try
{
System.Reflection.AssemblyName testAssembly = System.Reflection.AssemblyName.GetAssemblyName(#"C:\Windows\Microsoft.NET\Framework\v3.5\System.Net.dll");
System.Console.WriteLine("Yes, the file is an assembly.");
}
catch (System.IO.FileNotFoundException)
{
System.Console.WriteLine("The file cannot be found.");
}
catch (System.BadImageFormatException)
{
System.Console.WriteLine("The file is not an assembly.");
}
catch (System.IO.FileLoadException)
{
System.Console.WriteLine("The assembly has already been loaded.");
}
}
}
// Output (with .NET Framework 3.5 installed):
// Yes, the file is an assembly.
Framework is the highest installed version, SP is the service pack for that version.
RegistryKey installed_versions = Registry.LocalMachine.OpenSubKey(#"SOFTWARE\Microsoft\NET Framework Setup\NDP");
string[] version_names = installed_versions.GetSubKeyNames();
//version names start with 'v', eg, 'v3.5' which needs to be trimmed off before conversion
double Framework = Convert.ToDouble(version_names[version_names.Length - 1].Remove(0, 1), CultureInfo.InvariantCulture);
int SP = Convert.ToInt32(installed_versions.OpenSubKey(version_names[version_names.Length - 1]).GetValue("SP", 0));
For .Net 4.5
using System;
using Microsoft.Win32;
...
private static void Get45or451FromRegistry()
{
using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey("SOFTWARE\\Microsoft\\NET Framework Setup\\NDP\\v4\\Full\\")) {
int releaseKey = Convert.ToInt32(ndpKey.GetValue("Release"));
if (true) {
Console.WriteLine("Version: " + CheckFor45DotVersion(releaseKey));
}
}
}
...
// Checking the version using >= will enable forward compatibility,
// however you should always compile your code on newer versions of
// the framework to ensure your app works the same.
private static string CheckFor45DotVersion(int releaseKey)
{
if (releaseKey >= 393273) {
return "4.6 RC or later";
}
if ((releaseKey >= 379893)) {
return "4.5.2 or later";
}
if ((releaseKey >= 378675)) {
return "4.5.1 or later";
}
if ((releaseKey >= 378389)) {
return "4.5 or later";
}
// This line should never execute. A non-null release key should mean
// that 4.5 or later is installed.
return "No 4.5 or later version detected";
}

For similar purposes we use custom MSBuild fragments with common properties that we want to share between the projects, like this (build.common.props file):
<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<TargetFrameworkVersion>v2.0</TargetFrameworkVersion>
<PlatformToolset>v90</PlatformToolset>
<OutputPath>$(SolutionDir)..\bin\$(PlatformPath)\$(Configuration)\</OutputPath>
<!-- whatever you need here -->
</PropertyGroup>
</Project>
And then we just include this fragment to real VS projects we want to apply these properties to:
<?xml version="1.0" encoding="utf-8"?>
<Project DefaultTargets="Build" ToolsVersion="12.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<PropertyGroup>
<CommonProps>$(SolutionDir)..\Build\build.common.props</CommonProps>
</PropertyGroup>
<Import Project="$(CommonProps)" />
<!-- the rest of the project -->
</Project>
We handle a lot of things using this approach:
common properties, as you mentioned
static analysis (FxCop, StyleCop)
digital sign of assemblies
etc.
The only disadvantage that you need to include these MSBuild fragments into each project file, but once you do that, you have all the benefits of modular build system that is easy to manage and update.

You could go the search & replace Regex way with a handwritten C#, Script, powershell or similar. But it has the following problems:
Difficult to read (Read your pretty regex in three or more months)
Difficult to enhance(New regex for new search/replace/check feature)
Easy to break (a new release/format of ms build project or a not forecast tag may not work)
Harder to test (you must check that no unintended match occurs)
Difficult to maintain (because of the above)
and the following advantages:
Not doing any extra validation which (may) let it work on any kind of project (mono or visual).
Doesn't care about \r :)
The best could be to use the Microsoft.Build.Evaluation
and build a C# tool which does all your testing/checking/fix and so on.
I've done a command line tool that use a sourcefile list (used by Mono) and update sources of csproj and another which dumps on console the csproj content. It was easy to do, pretty straightforward and easy to test also.
However, it may fail (as I've experienced it) on projects modified by "non" Ms tool (like Mono Studio) or because of missing \r....
Anyway, you can always handle it with an exception catch and a good message.
Here a sample by using Microsoft.Build.dll (don't use Microsof.Build.Engine as it is obsolete):
using System;
using Microsoft.Build.Evaluation;
internal class Program
{
private static void Main(string[] args)
{
var project = new Project("PathToYourProject.csproj");
Console.WriteLine(project.GetProperty("TargetFrameworkVersion", true, string.Empty));
Console.WriteLine(project.GetProperty("Platform", true, string.Empty));
Console.WriteLine(project.GetProperty("WarningLevel", true, string.Empty));
Console.WriteLine(project.GetProperty("TreatWarningsAsErrors", true, "false"));
Console.WriteLine(project.GetProperty("OutputPath", false, string.Empty));
Console.WriteLine(project.GetProperty("SignAssembly", true, "false"));
Console.WriteLine(project.GetProperty("AssemblyName", false, string.Empty));
Console.ReadLine();
}
}
public static class ProjectExtensions
{
public static string GetProperty(this Project project, string propertyName, bool afterEvaluation, string defaultValue)
{
var property = project.GetProperty(propertyName);
if (property != null)
{
if (afterEvaluation)
return property.EvaluatedValue;
return property.UnevaluatedValue;
}
return defaultValue;
}
}

I also faced this issue and created a small solution that creates a csv file with details to identifies the inconsistences. You can look at it in this url
https://github.com/gdlmanuv/VSProjectConsistencyChecker

Automatically update version number

I would like the version property of my application to be incremented for each build but I'm not sure on how to enable this functionality in Visual Studio (2005/2008). I have tried to specify the AssemblyVersion as 1.0.* but it doesn't get me exactly what I want.
I'm also using a settings file and in earlier attempts when the assembly version changed my settings got reset to the default since the application looked for the settings file in another directory.
I would like to be able to display a version number in the form of 1.1.38 so when a user finds a problem I can log the version they are using as well as tell them to upgrade if they have an old release.
A short explanation of how the versioning works would also be appreciated. When does the build and revision number get incremented?

With the "Built in" stuff, you can't, as using 1.0.* or 1.0.0.* will replace the revision and build numbers with a coded date/timestamp, which is usually also a good way.
For more info, see the Assembly Linker Documentation in the /v tag.
As for automatically incrementing numbers, use the AssemblyInfo Task:
AssemblyInfo Task
This can be configured to automatically increment the build number.
There are 2 Gotchas:
Each of the 4 numbers in the Version string is limited to 65535. This is a Windows Limitation and unlikely to get fixed.
Why are build numbers limited to 65535?
Using with with Subversion requires a small change:
Using MSBuild to generate assembly version info at build time (including SubVersion fix)
Retrieving the Version number is then quite easy:
Version v = Assembly.GetExecutingAssembly().GetName().Version;
string About = string.Format(CultureInfo.InvariantCulture, #"YourApp Version {0}.{1}.{2} (r{3})", v.Major, v.Minor, v.Build, v.Revision);
And, to clarify: In .net or at least in C#, the build is actually the THIRD number, not the fourth one as some people (for example Delphi Developers who are used to Major.Minor.Release.Build) might expect.
In .net, it's Major.Minor.Build.Revision.

VS.NET defaults the Assembly version to 1.0.* and uses the following logic when auto-incrementing: it sets the build part to the number of days since January 1st, 2000, and sets the revision part to the number of seconds since midnight, local time, divided by two. See this MSDN article.
Assembly version is located in an assemblyinfo.vb or assemblyinfo.cs file. From the file:
' Version information for an assembly consists of the following four values:
'
' Major Version
' Minor Version
' Build Number
' Revision
'
' You can specify all the values or you can default the Build and Revision Numbers
' by using the '*' as shown below:
' <Assembly: AssemblyVersion("1.0.*")>
<Assembly: AssemblyVersion("1.0.0.0")>
<Assembly: AssemblyFileVersion("1.0.0.0")>

I have found that it works well to simply display the date of the last build using the following wherever a product version is needed:
System.IO.File.GetLastWriteTime(System.Reflection.Assembly.GetExecutingAssembly().Location).ToString("yyyy.MM.dd.HH.mm.ss")
Rather than attempting to get the version from something like the following:
System.Reflection.Assembly assembly = System.Reflection.Assembly.GetExecutingAssembly();
object[] attributes = assembly.GetCustomAttributes(typeof(System.Reflection.AssemblyFileVersionAttribute), false);
object attribute = null;
if (attributes.Length > 0)
{
attribute = attributes[0] as System.Reflection.AssemblyFileVersionAttribute;
}

[Visual Studio 2017, .csproj properties]
To automatically update your PackageVersion/Version/AssemblyVersion property (or any other property), first, create a new Microsoft.Build.Utilities.Task class that will get your current build number and send back the updated number (I recommend to create a separate project just for that class).
I manually update the major.minor numbers, but let MSBuild to automatically update the build number (1.1.1, 1.1.2, 1.1.3, etc. :)
using Microsoft.Build.Framework;
using System;
using System.Collections.Generic;
using System.Text;
public class RefreshVersion : Microsoft.Build.Utilities.Task
{
[Output]
public string NewVersionString { get; set; }
public string CurrentVersionString { get; set; }
public override bool Execute()
{
Version currentVersion = new Version(CurrentVersionString ?? "1.0.0");
DateTime d = DateTime.Now;
NewVersionString = new Version(currentVersion.Major,
currentVersion.Minor, currentVersion.Build+1).ToString();
return true;
}
}
Then call your recently created Task on MSBuild process adding the next code on your .csproj file:
<Project Sdk="Microsoft.NET.Sdk">
...
<UsingTask TaskName="RefreshVersion" AssemblyFile="$(MSBuildThisFileFullPath)\..\..\<dll path>\BuildTasks.dll" />
<Target Name="RefreshVersionBuildTask" BeforeTargets="Pack" Condition="'$(Configuration)|$(Platform)'=='Release|AnyCPU'">
<RefreshVersion CurrentVersionString="$(PackageVersion)">
<Output TaskParameter="NewVersionString" PropertyName="NewVersionString" />
</RefreshVersion>
<Message Text="Updating package version number to $(NewVersionString)..." Importance="high" />
<XmlPoke XmlInputPath="$(MSBuildProjectDirectory)\mustache.website.sdk.dotNET.csproj" Query="/Project/PropertyGroup/PackageVersion" Value="$(NewVersionString)" />
</Target>
...
<PropertyGroup>
..
<PackageVersion>1.1.4</PackageVersion>
..
When picking Visual Studio Pack project option (just change to BeforeTargets="Build" for executing the task before Build) the RefreshVersion code will be triggered to calculate the new version number, and XmlPoke task will update your .csproj property accordingly (yes, it will modify the file).
When working with NuGet libraries, I also send the package to NuGet repository by just adding the next build task to the previous example.
<Message Text="Uploading package to NuGet..." Importance="high" />
<Exec WorkingDirectory="$(MSBuildProjectDirectory)\bin\release" Command="c:\nuget\nuget push *.nupkg -Source https://www.nuget.org/api/v2/package" IgnoreExitCode="true" />
c:\nuget\nuget is where I have the NuGet client (remember to save your NuGet API key by calling nuget SetApiKey <my-api-key> or to include the key on the NuGet push call).
Just in case it helps someone ^_^.

What source control system are you using?
Almost all of them have some form of $ Id $ tag that gets expanded when the file is checked in.
I usually use some form of hackery to display this as the version number.
The other alternative is use to use the date as the build number: 080803-1448

Some time ago I wrote a quick and dirty exe that would update the version #'s in an assemblyinfo.{cs/vb} - I also have used rxfind.exe (a simple and powerful regex-based search replace tool) to do the update from a command line as part of the build process. A couple of other helpfule hints:
separate the assemblyinfo into product parts (company name, version, etc.) and assembly specific parts (assembly name etc.). See here
Also - i use subversion, so I found it helpful to set the build number to subversion revision number thereby making it really easy to always get back to the codebase that generated the assembly (e.g. 1.4.100.1502 was built from revision 1502).

If you want an auto incrementing number that updates each time a compilation is done, you can use VersionUpdater from a pre-build event. Your pre-build event can check the build configuration if you prefer so that the version number will only increment for a Release build (for example).

Here is a handcranked alternative option: This is a quick-and-dirty PowerShell snippet I wrote that gets called from a pre-build step on our Jenkins build system.
It sets the last digit of the AssemblyVersion and AssemblyFileVersion to the value of the BUILD_NUMBER environment variable which is automatically set by the build system.
if (Test-Path env:BUILD_NUMBER) {
Write-Host "Updating AssemblyVersion to $env:BUILD_NUMBER"
# Get the AssemblyInfo.cs
$assemblyInfo = Get-Content -Path .\MyShinyApplication\Properties\AssemblyInfo.cs
# Replace last digit of AssemblyVersion
$assemblyInfo = $assemblyInfo -replace
"^\[assembly: AssemblyVersion\(`"([0-9]+)\.([0-9]+)\.([0-9]+)\.[0-9]+`"\)]",
('[assembly: AssemblyVersion("$1.$2.$3.' + $env:BUILD_NUMBER + '")]')
Write-Host ($assemblyInfo -match '^\[assembly: AssemblyVersion')
# Replace last digit of AssemblyFileVersion
$assemblyInfo = $assemblyInfo -replace
"^\[assembly: AssemblyFileVersion\(`"([0-9]+)\.([0-9]+)\.([0-9]+)\.[0-9]+`"\)]",
('[assembly: AssemblyFileVersion("$1.$2.$3.' + $env:BUILD_NUMBER + '")]')
Write-Host ($assemblyInfo -match '^\[assembly: AssemblyFileVersion')
$assemblyInfo | Set-Content -Path .\MyShinyApplication\Properties\AssemblyInfo.cs -Encoding UTF8
} else {
Write-Warning "BUILD_NUMBER is not set."
}