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Issues with .Net Assembly Binding Redirection between .Net 2.0, 3.0 and 3.5 to .Net 4.0 and 4.5 (relating to SharePoint 2010 and 2013)

After about three hours of uncertainty as to why it didn’t work… a last ditch test and a 3am eureka moment converged to the following:

So a bit of backstory… the company I am working for, without going into the sensitive details, was writing a console app that we wanted to work against both SharePoint 2010 and SharePoint 2013.  Well there’s lots of hacky was to do that, including two different code brancehs which then need to be kept in sync or one code branch but doubling up project files and solutions in the folders, one pointing to SP2010 and one at SP2013… We use TFS build services and so any option would work, but most a management nightmares… so on being asked I suggested we use the assembly binding redirection (just like SharePoint itself does for loading webparts from older versions), as it’s the easiest to maintain.

So we tried… and after a good number of hours by another dev, and then by myself also for three hours, so couldn’t figure out why it didn’t work.  It would compile fine, and using the FUSLOGVW.EXE we were able to see the redirect was occuring, but then it wasn’t able to find the SharePoint 2013 assemblies (version 15).  All we had was a cryptic message at the end of the fusion log about “GAC Lookup was unsuccessful”.

So we ended the day with a big WTF?!?!

Well, so about 2 mins after I logged off, I decided to try one more thing and got a build working by changing the target framework to be .Net 4.5… a step forward.  Although this helped for SharePoint 2013 all of a sudden, it stopped working for SharePoint 2010, again complaining about not being able to find SharePoint.  Odd… but it’s something.

Then at 3am in the morning, the EUREKA moment happened… I figured out ‘why’, and then the details to make it all come together. The problem is that .Net 4.0 and above is a different GAC location now (it’s now in the place it should have always been).  If the project is a .Net Framework 3.5 project then it’s looking in the wrong GAC for the SP2013 assemblies (since they are .Net 4.5).  This was the whole reason it didn’t work from the beginning; when compiled to the right target framework, you don’t even need your own the binding redirection entries since SharePoint actually includes the minimum ones as policies in the .Net 4.5 GAC.  Having made the project a .Net 4.5 project it would have worked fine on SP2013 without any config settings as it would have looked in the correct GAC.

There is a catch though that would seem to be SharePoint specific.  SharePoint 2010 actually checks to ensure the app is targetting the ‘supported’ .Net 3.5 framework.  What this means is that to run against SP 2010 the EXE needs to target a .Net v3.5, while to run against SP 2013 it needs to target .Net v4.5 (or v4.0, but v4.5 is better).  The project can reference the SP2010 assemblies and, if targeting to the correct framework, will automatically adapt for the basic Microsoft.SharePoint assembly (there is a ‘but’ here that didn’t affect our specific situation right now).

So the next question is, how do we have one project target two different framework versions… answer, we don’t.  Luckily for us, MSBuild allows us to pass in overriding values for many things, one of which being the TargetFrameworkVersion (and in support of that, the ToolsVersion if needed).  And so we can instead make two build definitions in TFS (or simply two MSBuild commands if you are using some other automated build tool), one that does the default (or we could explicitly target .Net 3.5) and the other that passes additional arguments to MSBuild to explicitly target .Net 4.5. (it might be possible that we could also do one build definition with two outputs, one for each framework also). Now when the builds are kicked off, the exact same code, project file, and solution is used, but the MSBuild overrides the version and gives us one for SP 2010 and one for SP 2013.

Here are the details of the changes to make.  Open the original solution and ensure that it’s targeting .Net 3.5, and that the SharePoint reference is pointing to the SP 2010 (v14) DLL. Create one build defintion to do the defaults, and then a second build definition and add additional MSBuild arguments (in TFS you can also add them per queued build if you wanted to test this first) of:

/tv:4.0 /p:TargetFrameworkVersion=v4.5

* Note, both build defintions would point to the same SharePoint 2010 build server, for the compile to work, and you will also need to ensure that the .net 4.5 is installed to the SharePoint 2010 build server also (this doesn’t affect SharePoint, but is required to pick the 4.5 target when compiling).

Now, when you kick off each build it should create one as a SP 2010 compatible EXE and one as a SP 2013 compatible EXE (if we wanted we could use more arguments to alter the EXE output name to make them distinct also, such as “MyToolForSharePoint2010.exe” and “MyToolForSharePoint2013.exe”).

One code base… one thing to maintain, driven by configuration.

 

Some useful references:

http://msdn.microsoft.com/en-us/library/bb383985(v=vs.90).aspx

http://stackoverflow.com/questions/12003475/override-target-framework-from-command-line

Packaging and Deployment – ‘missing types’ compiler errors using Visual Studio 2012 and SharePoint 2010 tools

For a while now, the team and I have been dealing with a odd behavior in Visual Studio 2012 and SharePoint 2010, disruptive to the point that I actually scripted out the whole build and packaging process from the command line just to package up our WSPs (SharePoint packages).  Basically it happened like this… we has a solution with a combination of Class Library projects and SharePoint projects, and were able to compile the projects individually or as a solution in Visual Studio, but when trying to package or deploy them to SharePoint via Visual Studio we would receive a variety of errors about missing types.  These missing types were all part of the class projects that were referenced by the SharePoint projects, providing a variety of utility classes and such, which all compiled fine when simply doing a build, but were reported as missing when we attempted to create SharePoint packages.

Well with no useful information from Visual Studio, the issue just sat on the side lines until either time or frustration found me.  The fact that we could compile from the command line using MSBUILD only added to the confusion, but gave us an opportunity to ignore the issue as long as possible.  But alas, all good things must come to an end, and I found myself in a situation where I needed to actually deploy from within Visual Studio, and so I looked again at the issue.

Well with a bit of speculation, and some criticism of the SharePoint tools for Visual Studio, here’s what seemed to be going on.  The SharePoint project templates and tools are designed for moving forward, and are not friendly to changes or reworking.  This is obvious in the management of features and packages, with the unfriendly two column UI for adding and removing items.  An important thing in SharePoint packages is sequence, however only one of the many item list in the SharePoint tool UIs provides buttons for reordering and unfortunately this is not the one.  In the case of this issue, it appears to be the package additional assemblies.  As time went by and code was refactored and moved to enhance reuse and organization, more project assemblies were added to the various packages.  However, the sequence of the assemblies isn’t easy to manipulate and can intermittently cause issues packaging issues when code a lower level project is changed, as the project additional assemblies appear to be recompiled during packaging either in a weird order or with weird references.

Without spending an inordinate amount of time looking into exactly why, what seemed to help mitigate the issue, was to open the package files in notepad and reorder the additional assemblies such that they would be added in the same order that they would naturally be compiled.  This seemed to clear up the issue, allowing to the SharePoint package projects to be published and deployed again.

So the lesson here would seem to be, make sure you monitor and reorder your package additional assemblies…

Feature contents is another one to watch for order, but that’s a different story.

SharePoint – An unexpected error has occurred or Object Reference Error in a site collection after reattaching a Content Database

2013/02/16 2 comments

After removing a content database from a SharePoint 2010 web application, so that I can restore a backup (for development purposes), upon reattaching the content database I was being plagued with an assortment of error message.

These included when trying to load the site, seeing both an “An unexpected error has occurred” and a simple server information block returned, and upon checking the logs seeing:

“System.NullReferenceException: Object reference not set to an instance of an object.    at Microsoft.SharePoint.SPSite.PreinitializeServer(SPRequest request)”

This would occur on a single web front end server in the development farm (yep, I have multiple WFEs in my development environment), while the other WFEs would load fine.

After a couple different investigations, I found out that one cause of single server site corruption after reattaching a SP content db is… it’s the PowerShell SharePoint CmdLets.

If you are running PowerShell and are using the SharePoint CmdLets (SPSite for example) to connect to that site (for the content database in question), if you try to reattach the content database while that PowerShell session is still open, the reattach goes fine, but the servers where PowerShell was open will fail load the site thereafter… even after reboots and all.

You need to close the PowerShell window and then reattach the content database (either by the Central Admin UI or from a new PowerShell window if you are using scripts).

Additionally, the W3SVC and SPADMIN and SPTIMER services can all cause the same problem, so I have found that restarting those also (I bundled it up into a single PowerShell cmdlet) ensures that I never saw this issue again.

Disable Password Prompts In Microsoft Word and Excel Automation

It’s not an easy task to automate MS Office, and especially to run it as a service or within a ASP.Net web site, but it is possible and with a little bit of hard work and research you can actually have a very stable interaction.  This is the first of my many "things to note" and "gotcha’s" I found when dealing with MS Office Automation, and it’s a long list.

Disabling Password Prompts in MS Word and Excel Automation, seemed to be a hot topic in a lot of forums with few insights to an answer, but here is the trick that I figured out.

First you have to accept that fact that you likely aren’t going to be able to open the password protected file, and that Word or Excel is going to fail the open request, so you have a COM Exception to catch.  The nice thing is that the Error Code returned from the exception is unique for password issue so you can catch it specifically and deal with it (either tell the user or simply ignore it, whatever you want).  Again I will post a sample with the codes soon, but if you try to open a password protected file and hit cancel you will see the exception returned so you can get the code from there.

Now onto the second and most important point, the brilliant engineers at Microsoft figured that if a document isn’t password protected then there is no point in even trying to use any password supplied.  So basically… enter a garbage password into the various password fields (something around 8 chars seems fine; too many though and it causes another exception all the time).  Both word and Excel behave the same way, only using the password when the document is protected, and so normal documents will open fine since they won’t use the password, and documents that require a password will use the garbage one you provided instead of prompting, and will simply fail with ‘Invalid password’ which you can catch and handle.

   1:  const uint COM_CODE_BADPASSWORD = 0x800A1520;
   2:  const string OPEN_OPTION_MOCK_PASSWORD = "GARBAGE1";
   3:   
   4:  object missingValue = Type.Missing;
   5:  object fileNameObject = fileName;
   6:  object confirmConversions = false;
   7:  object openAsReadOnly = true;
   8:  object addToRecentFiles = false;
   9:  object passwordDocumentObject = OPEN_OPTION_MOCK_PASSWORD;
  10:  object passwordTemplateObject = OPEN_OPTION_MOCK_PASSWORD;
  11:  object revertObject = missingValue;
  12:  object writePasswordDocumentObject = OPEN_OPTION_MOCK_PASSWORD;
  13:  object writePasswordTemplateObject = OPEN_OPTION_MOCK_PASSWORD;
  14:  object formatObject = missingValue;
  15:   
  16:  object doNotSaveChanges = WdSaveOptions.wdDoNotSaveChanges;
  17:   
  18:  try
  19:  {
  20:      // Using OpenOld is documented to be more compatible with older versions of Word.
  21:      // Word only tries the password if it needs it.
  22:      Document document = wordApplication.Documents.OpenOld(
  23:          ref fileNameObject,
  24:          ref confirmConversions,
  25:          ref openAsReadOnly,
  26:          ref addToRecentFiles,
  27:          ref passwordDocumentObject,
  28:          ref passwordTemplateObject,
  29:          ref revertObject,
  30:          ref writePasswordDocumentObject,
  31:          ref writePasswordTemplateObject,
  32:          ref formatObject
  33:          );
  34:   
  35:      // Do stuff with the document.
  36:   
  37:      document.Close(ref doNotSaveChanges, ref missingValue, ref missingValue);
  38:   
  39:  }
  40:  catch (COMException ex)
  41:  {
  42:      if (((uint) comException.ErrorCode) == COM_CODE_BADPASSWORD)
  43:      {
  44:          Debug.WriteLine("Detected a password protected Word document.");
  45:      }
  46:      else
  47:      {
  48:          throw;
  49:      }
  50:  }

You may ask, that’s fine for Word and Excel, but what about the other office apps… well unfortunately I haven’t tried Publisher or Access since I didn’t have need at the time, but I did learn that PowerPoint doesn’t expose any way to enter a password for opening the presentation, so the old Dialog Killer thread was the only resolution we had, looking for visible dialog windows with a particular name and sending them a WM_CLOSE message (I say ‘visible’ dialog since we were also dealing with Acrobat which keeps invisible dialog boxes with the particular name we were monitoring, and visible only seems to work 100% of the time).

My next post will be on using the Automatic Recovery options to open documents and some very frustrating issues I had with those.

Using Find and Replace in Visual Studio .Net with Regular Expressions to Bulk Change Properties and Methods (or anything else)

This is a really quick sample of using Regular Expression in Visual Studio .Net to perform and intelligent Find and Replace.  Documented mainly so I don?t forget it.

The need for this arose when I was extracting properties from a class, so that the data of the class was separate from the functionality.

Unlike normal regular expressions, Visual Studio doesn?t let you reference groups derived in the expression, instead a different syntax is used as {?} to tag parts of the string, and then in your replacement expression you refer to those tagged parts by \n (0 being everything, and then 1, 2, 3, etc for the individual tagged parts).

Find

public {[A-Za-z\<\>\[\]]*} {[A-Za-z]*} \{ get\; private set\; \}

Replace With

public \1 \2 \{ get \{ return someClass\.\2\; \} private set \{ someClass.\2 \= value\; \} \}

Note* Be sure to check ?Use: Regular expressions? in the Find and Replace dialog box.

For more details see: http://msdn.microsoft.com/en-us/library/2k3te2cs(VS.80).aspx

Categories: Visual Studio .Net

Macro Framework For .Net To Dynamically Populate String Content

As much fun and functionality there is in the ToString() and formatting, sometimes you just want to whole lot of freedom to safely populate a message template with any and all values that might come along.

I found this need when I was building a SOAP API test harness, then again in a Printer test harness when I needed a way to pass arbitrary values into command scripts without wanting to complicate the process with tons of arguments or mudding the scripts with code to parse strings to split arguments out.

This framework is pretty simple but works well and is very flexible when it comes to the source of the actual values.  It is broken out into a set of very small, specifically tasked classes and interfaces, the primary ones of which follow here:

The MacroUtilities, which consists of a single public ExpandMacros method to take a string, and a callback to a MacroEvaluator.  The ExpandMacros method uses a light regular expression Replace call to enumerate all of the “$(?)” patterns in the string, and then calls the MacroEvaluator callback for each one, then repeating the process recursively to expand any macros with those just expanded.  Really this is the actual brains of the process, as the return string from the regular expression is the final expanded result.

The MacroExpander (IMacroExpander) is an instance wrapper of the MacroUtilities methods, which maintains the reference to a single MacroEvaluator callback.  It?s just a nice wrapper.

The MacroEvaluator delegate is used to pass reference to a method call that takes a macro name, everything within the opening “$(” and closing “)”, as a string and returns the expanded result.

The IMacroLibrary interface is used to expose a means for any implementing object to provide access to properties or just about any value by a name.  See the ReflectionMacroLibrary for an included library that uses .Net Reflection to map macro names to public properties automatically.

The last key part of the framework is the MacroManager which links the MacroExpander instance with a macro library.  The MacroManager implements the IMacroExpander and IMacroLibrary interfaces.  It is an instance of this class that ties all the others together and is the one to keep a link to and use by the rest of your application.

IMacroLibrary macroLibrary = someMacroLibrary;
IMacroExpander macroManager = new MacroManager(macroLibrary);
expandedMacroString = macroManager.ExpandMacros(templateMacroString);

The reference to “someMacroLibrary” can be any object that implements the IMacroRepository interface.  There are a number of examples in the attached file that demonstrates different libraries, and I will go more into those later.

Macro libraries can be nested, which is a real strength, so you can have a default set of macro and then expand upon them to include static or dynamic content on the fly.

Download Source

Categories: .Net Framework Tags: ,