Lambda Expressions in Immediate Window for VS2015

lambda expressions in immediate window for VS2015

This definitely works for me, looks like when I tick either Use Managed Compatibility Mode or Use the legacy C# and VB expression evaluators it stops working. Ensure those are unchecked.

Expression cannot contain lambda expression -Visual Studio 2015

Not sure about new feature in VS2015 but try setting the expression to a variable and then debug like

var data = lstClientDBs.Select(obj=>obj.ClientDatabase);

Strange but looks like MS declares that they have added that feature in VS2015 debugger (https://devblogs.microsoft.com/devops/support-for-debugging-lambda-expressions-with-visual-studio-2015/)

Also, you probably meant to use a Where() extension method than Select() like

var data = lstClientDBs.Where(obj=>obj.ClientDatabase);

Visual Studio Immediate Window - Lambda Expressions Aren't Allowed - Is there a Work-around or Alternative?

At times like this I always turn to the most excellent LINQPad.

The front page of the linked site (at time of writing) immediately jumps in with stuff about SQL but don't let that obscure how powerful and flexible this tool really is. I sort of treat it like an Immediate Window on steroids. I find it invaluable for working my way through complex LINQ queries.

If you can live without intellisense it's free (the intellisense version is chargeable).

Why can't I use lambda expressions in the Immediate Window?

Jaredpar explained it

Why is LINQ absent from debugger windows?

Why is LINQ absent from debugger windows (Part 2)?

Visual Studio debugging quick watch tool and lambda expressions

Lambda expressions, like anonymous methods, are actually very complex beasts. Even if we rule out Expression (.NET 3.5), that still leaves a lot of complexity, not least being captured variables, which fundamentally re-structure the code that uses them (what you think of as variables become fields on compiler-generated classes), with a bit of smoke and mirrors.

As such, I'm not in the least surprised that you can't use them idly - there is a lot of compiler work (and type generation behind the scenes) that supports this magic.

Expression not supported when debugging lambda expressions

After running several tests (no post/article on this topic found as a reference), I came to verdict that debugging of Lambda expressions does not work on Xamarin with Xamarin debugger.

Same code/expression does normally work on standard application:

This seems to be unrelated to version of .NET, as downgrading to version 4.0 (on Console app), still provide same debug results.

I have noted that in properties of Android project, there is an option called "debugger" and values to choose from: Xamarin, Microsoft Standard debug of Console app is most likely with the Microsoft one - which might have full support of debugging the Lambda expression.

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