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It's time to remind people about Fusion. Mostly because I don't see as many people using it as should. I mentioned it as long as six (!) years ago and it's still useful. I used it just this week with .NET 4.

Sometimes when an assembly doesn't load, there's still a sense/feeling that "something in the black box has broken." For some folks, the black box is larger and obscures more, than for others. My point is, if you know where to look, there is no box at all.

When it comes to assemblies there's three "times" to know about:

  • Binding before it happens - What do you want?
    • ILDASM or Reflector will tell you what your assembly wants (what it was compiled against)
  • Binding as it happens - Where does it look?
    • Fusion (the Assembly Binding Log Viewer) will show you all assembly binds if you set the HKLM\Software\Microsoft\Fusion\ForceLog registry value to 1
  • Binding after it happens - What did you get?
    • Process Explorer will tell you what DLL (assembly) is loaded in memory and from where it came.

Here's an example of how a tiny bit of digging saved me hours of confusion recently when I hit an unusual edge case. I was doing a build of sample that was showing C# interop-ing with IronPython, but I was using a daily build of .NET 4 and a random build of IronPython.

Assembly Binding Log ViewerI made a mistake and had some really old DLLs floating around that I shouldn't have had. My symptom was a FileNotFoundException for the file "System.Dynamic.dll." I KNEW it was in the GAC (Global Assembly Cache) and I could SEE it as a reference DLL in my directory. Can't find the file? Dude, it's right there!

Turning on Fusion Logging

You probably have a tool to help on your development system already. Type "Fusion" in the Start Menu. The Assembly Binding Log Viewer, or "Fusion Log Viewer" will tell the CLR to load assembling binding/loading activities to a folder, then let you see them.

Be sure to run it as Administrator if you want to change the Settings, otherwise they'll be grayed out.

Alternatively, just set the Registry keys your self. (I just memorized them, as I set them all the time.) Set HKLM\Software\Microsoft\Fusion\ForceLog registry value to 1 and HKLM\Software\Microsoft\Fusion\LogPath registry value to C:\FusionLogs or some path that exists.

Personally, I leave this on all the time on my dev machines (there's a small speed hit) and just clean the folder out every once in a while.

Solving My Binding Problem

Once I turned on Fusion Logging I could immediately see a failure in my folder:

The operation failed.
Bind result: hr = 0x80070002. The system cannot find the file specified.

Assembly manager loaded from: C:\Windows\Microsoft.NET\Framework\v4.0.xxxxx\clr.dll
Running under executable C:\Users\Scott\Desktop\TechEd09\FX4\Demo 5 - DLR\Two.IronPythonInterop\bin\Debug\Two.IronPythonInterop.exe
--- A detailed error log follows.

=== Pre-bind state information ===
LOG: User = HANSELMAN-DEV10\Scott
LOG: DisplayName = System.Dynamic, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
LOG: Appbase = file:///C:/Users/Scott/Desktop/TechEd09/FX4/Demo 5 - DLR/Two.IronPythonInterop/bin/Debug/
LOG: Initial PrivatePath = NULL
LOG: Dynamic Base = NULL
LOG: Cache Base = NULL
LOG: AppName = Two.IronPythonInterop.exe
Calling assembly : IronPython, Version=2.6.0.1, Culture=neutral, PublicKeyToken=31bf3856ad364e35.
===
LOG: This bind starts in default load context.
LOG: No application configuration file found.
LOG: Using host configuration file:
LOG: Using machine configuration file from C:\Windows\Microsoft.NET\Framework\v4.0.xxxxx\config\machine.config.
LOG: Post-policy reference: System.Dynamic, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089
LOG: GAC Lookup was unsuccessful.
LOG: Attempting download of new URL file:///C:/Users/Scott/Desktop/TechEd09/FX4/Demo 5 - DLR/Two.IronPythonInterop/bin/Debug/System.Dynamic.DLL.
LOG: Attempting download of new URL file:///C:/Users/Scott/Desktop/TechEd09/FX4/Demo 5 - DLR/Two.IronPythonInterop/bin/Debug/System.Dynamic/System.Dynamic.DLL.
LOG: Attempting download of new URL file:///C:/Users/Scott/Desktop/TechEd09/FX4/Demo 5 - DLR/Two.IronPythonInterop/bin/Debug/System.Dynamic.EXE.
LOG: Attempting download of new URL file:///C:/Users/Scott/Desktop/TechEd09/FX4/Demo 5 - DLR/Two.IronPythonInterop/bin/Debug/System.Dynamic/System.Dynamic.EXE.
LOG: All probing URLs attempted and failed.

You can see that it's looking all over for the file, first in the GAC< then all over the local folders before it gives up. Hm. Why isn't this working? I can see the file sitting right there.

Well, what's the public key token for this signed assembly? I can run "sn -T" on the file:

C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.0>
sn -T System.Dynamic.dll

Microsoft (R) .NET Framework Strong Name Utility Version 4.0.xxxxx.1
Copyright (c) Microsoft Corporation. All rights reserved.

Public key token is b03f5f7f11d50a3a

Wha? What's b03whatever? That's not b77whatever like the one my app is looking for! Looks like my sample app had reference not only an old version of System.Dynamic, but one with a completely different public key. That's what I get for not cleaning out my obj directories between daily builds.

This could have been just by setting the registry keys and watching the c:\fusionlogs folder, but the Fusion Log Viewer makes the process more user-friendly.

If you're debugging version number mismatches or strong-name mismatches, Fusion will ALWAYS tell you what's really going on. There is no Black Box.

Related Links



I've posted twice so far on .NET 4, first on ASP.NET 4, then on improvements in C# around dynamism and PIAs as well as the COM Binder. Now "dynamic."

So I asked this guy, what's up with the dynamic keyword, and what type was it exactly? I mean, C# isn't dynamic, right? He says:

"Oh, well it's statically-typed as a dynamic type."

Then my brain exploded and began to leak out my ears. Honestly, though, it took a second. Here's a good example from some of Ander's slides:

Calculator calc = GetCalculator();
int sum = calc.Add(10, 20);

That's the creation of an object, invokation of a method, and the collection of a return value. This is the exact same code, as the "var" type is figured out at compile time.

var calc = GetCalculator();
int sum = calc.Add(10, 20);

If you wanted to do the exact same thing, except with Reflection (like if it were some other class, maybe old-COM interop, or something where the compiler didn't know a priori that Add() was available, etc) you'd do this:

object calc = GetCalculator();
Type calcType = calc.GetType();
object res = calcType.InvokeMember("Add",
BindingFlags.InvokeMethod, null,
new object[] { 10, 20 });
int sum = Convert.ToInt32(res);

It's pretty horrible to look at, of course. If the object is some dynamic thing (from any number of sources), we can do this:

dynamic calc = GetCalculator();
int sum = calc.Add(10, 20);

And get the dynamic method invocation and conversion of the return type. Basically it looks just like we're calling any other object.

Dynamism?

Here's the differences you see while coding. Hovering over the keyword gives me this nice tooltip.

image

When I hit the "." expecting intellisense to save me from my ignorance:

image 

I'm told this is a dynamic expression that will be resolved at runtime.

Here's a C# program calling a method in a python (.py) file:

ScriptRuntime py = Python.CreateRuntime();
dynamic random = py.UseFile("random.py");

//Make an array of numbers
var items = Enumerable.Range(1, 7).ToArray();

random.shuffle(items);

Here we're passing in an array if ints (System.Int32[]) into the Python 'shuffle' method and it works just fine.

image

The DLR basically enables everyone to talk to everyone. That includes not just Python and Ruby, but Silverlight, Office/COM, and others.

What price REPL?

John Lam has a great post about his TechEd talk where he took a spin on a traditional REPL (READ-EVAL-PRINT-LOOP) using the DLR. He even allows switching back and forth between languages, which is odd/interesting.

John's even put the code for his REPL up on GitHub. Why is this interesting? Well...

Screenshot of John Lam's REPL/editor

He took his REPL and embedded it into an example Open Source app, specifically Witty, a WPF Twitter Client. Why he didn't use BabySmash is beyond me. ;) Check it out, as well as the source code diff for Witty on John's blog.

It'll be nice to have this kind of dynamic stuff just baked in and waiting for me to use it.



Just got a great tweet from Jeremiah Morrill about .NET 4.

"Office and COM Interop that is actually fun to do" Show me! Until then, I'm calling shenanigans.

I love a challenge! In my first Whirlwind Tour post on ASP I mentioned how COM Interop and Office Interop was fun with 4.

I've done a lot of COM Interop with C# and a LOT of Office Automation. Once upon a time, I worked at a company called Chrome Data, and we created a Fax Server with a Digiboard. Folks would call into a number, and the person who took the order would pick the make/model/style/year of the car and "instantly" fax a complete report about the vehicle. It used VB3, SQL Server 4.21 and Word 6.0 and a magical thing called "OLE Automation."

Fast forward 15 years and I sent an email to Mads Torgerson, a PM on C# that said:

I’m doing a sample for a friend where I’m simply spinning through an Automation API over a Word Doc to get and change some CustomDocumentProperties.

I’m really surprised at how current C# sucks at this. Of course, it makes sense, given all the IDispatch code in Word, but still. Dim != var as they say. Fix it!

Well, everything except "fix it!" is true. I added that just now. ;) I did a post on this a while back showing how scary the C# code was. This is/was somewhere where Visual Basic truly excels. I vowed to only use VB for Office Automation code after this fiasco.

If you want to melt your brain, check out the old code. No joke. I've collapsed the block because it's too scary. See the "ref missings"? The reflection? The Get/Sets? Scandalous!

{
ApplicationClass WordApp = new ApplicationClass();
WordApp.Visible = true;
object missing = System.Reflection.Missing.Value;
object readOnly = false;
object isVisible = true;
object fileName = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, @"..\..\..\NewTest.doc");
Microsoft.Office.Interop.Word.Document aDoc = WordApp.Documents.Open(
ref fileName,ref missing,ref readOnly,ref missing,
ref missing,ref missing,ref missing,ref missing,
ref missing,ref missing,ref missing,ref isVisible,
ref missing,ref missing,ref missing,ref missing);

aDoc.Activate();

string propertyValue = GetCustomPropertyValue(aDoc, "CustomProperty1");
SetCustomPropertyValue(aDoc, "CustomProperty1", "Hanselman");

foreach (Range r in aDoc.StoryRanges)
{
r.Fields.Update();
}
}

public string GetCustomPropertyValue(Document doc, string propertyName)
{
object oDocCustomProps = doc.CustomDocumentProperties;
Type typeDocCustomProps = oDocCustomProps.GetType();
object oCustomProp = typeDocCustomProps.InvokeMember("Item",
BindingFlags.Default |
BindingFlags.GetProperty,
null, oDocCustomProps,
new object[] { propertyName });

Type typePropertyValue = oCustomProp.GetType();
string propertyValue = typePropertyValue.InvokeMember("Value",
BindingFlags.Default |
BindingFlags.GetProperty,
null, oCustomProp,
new object[] { }).ToString();

return propertyValue;
}

public void SetCustomPropertyValue(Document doc, string propertyName, string propertyValue)
{
object oDocCustomProps = doc.CustomDocumentProperties;
Type typeDocCustomProps = oDocCustomProps.GetType();
typeDocCustomProps.InvokeMember("Item",
BindingFlags.Default |
BindingFlags.SetProperty,
null, oDocCustomProps,
new object[] { propertyName, propertyValue });
}

Fast forward to C# under .NET 4.

var WordApp = new ApplicationClass();
WordApp.Visible = true;
string fileName = @"NewTest.doc";
Document aDoc = WordApp.Documents.Open(fileName, ReadOnly: true, Visible: true);
aDoc.Activate();

string propertyValue = aDoc.CustomDocumentProperties["FISHORTNAME"].Value;
aDoc.CustomDocumentProperties["FISHORTNAME"].Value = "HanselBank";
string newPropertyValue = aDoc.CustomDocumentProperties["FISHORTNAME"].Value

foreach (Range r in aDoc.StoryRanges)
{
foreach (Field b in r.Fields)
{
b.Update();
}
}

See how all the crap that was originally reflection gets dispatched dynamically? But that's not even that great an example.

Word and Excel Automation with C# 4

That's just an example from Jonathan Carter and Jason Olson that gets running processes (using LINQ, woot) then makes a chart in Excel, then puts the chart in Word.

using System;
using System.Diagnostics;
using System.Linq;
using Excel = Microsoft.Office.Interop.Excel;
using Word = Microsoft.Office.Interop.Word;

namespace One.SimplifyingYourCodeWithCSharp
{
class Program
{
static void Main(string[] args)
{
GenerateChart(copyToWord: true);
}

static void GenerateChart(bool copyToWord = false)
{
var excel = new Excel.Application();
excel.Visible = true;
excel.Workbooks.Add();

excel.get_Range("A1").Value2 = "Process Name";
excel.get_Range("B1").Value2 = "Memory Usage";

var processes = Process.GetProcesses()
.OrderByDescending(p => p.WorkingSet64)
.Take(10);
int i = 2;
foreach (var p in processes)
{
excel.get_Range("A" + i).Value2 = p.ProcessName;
excel.get_Range("B" + i).Value2 = p.WorkingSet64;
i++;
}

Excel.Range range = excel.get_Range("A1");
Excel.Chart chart = (Excel.Chart)excel.ActiveWorkbook.Charts.Add(
After: excel.ActiveSheet);

chart.ChartWizard(Source: range.CurrentRegion,
Title: "Memory Usage in " + Environment.MachineName);

chart.ChartStyle = 45;
chart.CopyPicture(Excel.XlPictureAppearance.xlScreen,
Excel.XlCopyPictureFormat.xlBitmap,
Excel.XlPictureAppearance.xlScreen);

if (copyToWord)
{
var word = new Word.Application();
word.Visible = true;
word.Documents.Add();

word.Selection.Paste();
}
}
}
}

Notice the named parameters in C#, like 'Title: "whatever"' and "copyToWord: true"?

PIAs no long stand for Pain in the *ss - Type Equivalence and Embedded Interop Assemblies

Primary Interop Assemblies are .NET assemblies that bridge the gap between a .NET app and a COM server. They are also a PIA, ahem. When there's articles about your technology on the web called "Common Pitfalls With ______" you know there's trouble.

Typically you reference these Interop assemblies in Visual Studio and they show up, predictably, as references in your assembly. Here's a screenshot with the project on the right, and the assembly under Reflector on the left.

image

This means that those PIAs better be deployed on the end user's machine. Some PIAs can be as large as 20 megs or more! That's because for each COM interface, struct, enum, etc, there is a managed equivalent for marshalling data. That sucks, especially if I just want to make a chart and I'm not using any other types. It's great that Office has thousands of types, but don't make me carry them all around.

However, now I can click on Properties for these references and click Embed Interop Types = true. Now, check the screenshot. The references are gone and new types have appeared.

 image

Just the types I was using are now embedded within my application. However, since the types are equivalent, the runtime handles this fact and we don't have to do anything.

This all adds up to Office and COM Interop that is actually fun to do. Ok, maybe not fun, but better than a really bad paper cut. Huh, Jeremiah? ;)



As web programmers, we use a lot of strings to move data around the web. Often we’ll use a string to represent a date or an integer or a boolean. Basically "1" in instead of 1, or "April 1, 2009" rather than a proper ISO-8601 formatted culture-invariant date.

While these strings are flying around via HTTP it's not a huge deal, but sometimes this loose, even sloppy, use of strings can leak into our own code. We might find ourselves leaving the data times as strings longer and longer, or not even bothering to convert them to their proper type at all. This problem is made worse by the proliferation of JSON, and schema-less/namespace-less XML (that I've often called "angle-bracket delimited files" as they're no more useful than CSVs in that point.

.NET 4.0 is pretty much locked down, but version 4.1 still has some really cool "Futures" features that are being argued about. If we don't know the type of a string, or we want to leave the string, as a string, longer than usual, what if we had an class that could be both a string and another type, essentially deferring the decision until the variable is observed. For example:

StringOr<int> userInput= GetUserInput("Quantity"); 
string szUserInput=userInput.StringValue; 
int intUserInput=userInput.OtherValue;

Sometimes you just don't know, or can't know.

This reminds me of a similar, but orthogonal physics concept, that of the Heisenberg Uncertainty Principle. Sometimes you know that an object is a string, and sometimes you know how long it is, but you can’t know both at the same time.

One of my favorite jokes goes:

Heisenberg gets pulled over by the police. The officer asks, “Do you know how fast you were going?” Heisenberg answers, “No, but I know exactly where I am!”

This library doesn't solve THAT issue, with respect to strings, but we’ve got folks in DevDiv working on this and many other metaphysical - and physical - problems as they apply to computer science.

Big thanks to Eilon, who's working hard to get this pushed into the .NET 4.1 Base Class Library. Visit Eilon's blog for more details on this new library, more code, graphics and details on how Intellisense will handle this new case.

Hopefully, someone is working to make this important new library Open Source.

Your thoughts, Dear Reader?

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