.net - Read AssemblyFileVersion from AssemblyInfo post-compile

Question

How can one read the AssemblyFileVersion, or its components AssemblyFileMajorVersion, AssemblyFileMinorVersion, AssemblyFileBuildNumber, AssemblyFileRevision, within the .csproj, following compilation?

I have tried the following which pulls the information from the built assembly:

<Target Name="AfterCompile">
    <GetAssemblyIdentity AssemblyFiles="$(TargetPath)">
         <Output
             TaskParameter="Assemblies"
             ItemName="MyAssemblyIdentities"/>
    </GetAssemblyIdentity>
    <Message Text="AssemblyVersion = %(MyAssemblyIdentities.Version)" />
</Target>

But that retrieves the AssemblyVersion and not the AssemblyFileVersion. There does not seem to be a documented metadata entry for the latter. I also tried:

<Import Project="$(MSBuildExtensionsPath)ExtensionPackMSBuild.ExtensionPack.tasks" />
<Target Name="AfterCompile">
    <MSBuild.ExtensionPack.Framework.Assembly TaskAction="GetInfo" NetAssembly="$(TargetPath)">
        <Output TaskParameter="OutputItems" ItemName="Info" />
    </MSBuild.ExtensionPack.Framework.Assembly>
    <Message Text="AssemblyFileVersion = %(Info.FileVersion)" />
</Target>

Unfortunately, while this retrieves the correct value, it also file locks the assembly until VS2008 is closed.

Frankly, neither is what I want as I would rather read the information from the AssemblyInfo.cs directly. However, I cannot figure out how to do that. I assumed AssemblyInfo in the MSBuild Extensions was one way, but it seems focused on writing to the AssemblyInfo and not retrieving values from it.

How can I best accomplish this?

Answer 1

I've managed to solve this using a custom task. The class library DLL is as so (some code adjusted/eliminated for brevity):

using System;
using System.IO;
using System.Text.RegularExpressions;
using Microsoft.Build.Framework;

namespace GetAssemblyFileVersion
{
    public class GetAssemblyFileVersion : ITask
    {
        [Required]
        public string strFilePathAssemblyInfo { get; set; }
        [Output]
        public string strAssemblyFileVersion { get; set; }
        public bool Execute()
        {
            StreamReader streamreaderAssemblyInfo = null;
            Match matchVersion;
            Group groupVersion;
            string strLine;
            strAssemblyFileVersion = String.Empty;
            try
            {
                streamreaderAssemblyInfo = new StreamReader(strFilePathAssemblyInfo);
                while ((strLine = streamreaderAssemblyInfo.ReadLine()) != null)
                {
                    matchVersion = Regex.Match(strLine, @"(?:AssemblyFileVersion("")(?<ver>(d*).(d*)(.(d*)(.(d*))?)?)(?:""))", RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline | RegexOptions.ExplicitCapture);
                    if (matchVersion.Success)
                    {
                        groupVersion = matchVersion.Groups["ver"];
                        if ((groupVersion.Success) && (!String.IsNullOrEmpty(groupVersion.Value)))
                        {
                            strAssemblyFileVersion = groupVersion.Value;
                            break;
                        }
                    }
                }
            }
            catch (Exception e)
            {
                BuildMessageEventArgs args = new BuildMessageEventArgs(e.Message, string.Empty, "GetAssemblyFileVersion", MessageImportance.High);
                BuildEngine.LogMessageEvent(args);
            }
            finally { if (streamreaderAssemblyInfo != null) streamreaderAssemblyInfo.Close(); } 
            return (true);
        }
        public IBuildEngine BuildEngine { get; set; }
        public ITaskHost HostObject { get; set; }
    }
}

And in the project file:

<UsingTask AssemblyFile="GetAssemblyFileVersion.dll" TaskName="GetAssemblyFileVersion.GetAssemblyFileVersion" />
<Target Name="AfterCompile">
    <GetAssemblyFileVersion strFilePathAssemblyInfo="$(SolutionDir)AssemblyInfo.cs">
        <Output TaskParameter="strAssemblyFileVersion" PropertyName="strAssemblyFileVersion" />
    </GetAssemblyFileVersion>
    <Message Text="AssemblyFileVersion = $(strAssemblyFileVersion)" />
</Target>

I've tested this and it will read the updated version if you use MSBuild.ExtensionPack.VersionNumber.targets for auto-versioning.

Obviously, this could be easily extended so that a regex is passed from the project file to a more general-purpose custom task in order to obtain any match in any file.

---

Update 2009/09/03:

One additional change has to be made to make the ApplicationVersion update on each build. InitialTargets="AfterCompile" must be added to the <Project.... This was solved by Chao Kuo.