The code pattern of doing everything in IQueryProvider…

(Rambling) I’m taking another short foray into IQueryable land. From my learnings last time, In brief, I realized that IQueryable = Expression Tree, + QueryProvider, and that if you take a lazy approach to implementing IQueryable, then all the real work is happening inside QueryProvider.Execute(), where it can just retranslate the entire expression tree you…

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(WF4.5) Using CSharpValue<T> and CSharpReference<T> in .Net 4.5 – Compiling expressions–and changes in Visual Studio generated XAML

I’ve been publicizing for a while that Visual Studio 11 (still in Beta) supports C# expressions in workflow designer. Of course you might also possibly want to use C# or VB expressions by writing a workflow in code, instead of by building it in Visual Studio. There are actually a couple tricks to doing this,…

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(WF4) Less Known Features – Declarative Expressions using Activities, and ExpressionServices.Convert

If you’re exclusively using the Visual Studio workflow designer to design activities, you might go for a very long time (or forever) without discovering a particular System.Activities namespace, which is System.Activities.Expressions. The first reason you might never discover them is that none of the activities here are visible in the Visual Studio workflow toolbox by…

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(WF4) Adding VB namespace Imports to your workflow programmatically

These questions (paraphrased) have come up a bunch of times so it’s not that hard to find the answer, but I just rediscovered them so it’s on topic for today. “I want to add a namespace to the Imports designer automatically at design time, so the user doesn’t have to do it manually. How can…

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