Fix Symbol View In SyntaxTreeVizualizer

[bernd5]

See:

• Fix Symbol View In SyntaxTreeVizualizer #554
• Syntax Visualizer shows SyntaxNodes but no Symbols #504

=> Use custom TypeDescriptor to display Symbol-Data

[sharwell]

Do you know why a custom TypeDescriptor is needed for displaying ISymbol, but is not needed for displaying IOperation?

[bernd5]

What happens inside of the property grid is a call like this:

var props = TypeDescriptor.GetProperties(node, new Attribute[] { BrowsableAttribute.Yes });

which calls then (more or less):

new ReflectTypeDescriptionProvider().GetProperties(node.GetType())

For SyntaxNodes it returns some properties (perhaps because of some attributes). But for symbols it returns nothing.

[sharwell]

Ah, I bet it's because all the properties are explicitly implemented for symbols:

https://github.com/dotnet/roslyn/blob/d55444d009b3bb71f6893d17c6ae8cb714129445/src/Compilers/CSharp/Portable/Symbols/PublicModel/NamedTypeSymbol.cs#L24-L30

[bernd5]

That makes sense, we have the type of the Symbol implementation not the Symbol itself.

[bernd5]

We could use the adapter for all kinds of selected objects, it allows a better control...
For example we can print now "None" instead of an empty string. And we can print the result of functions without parameters...

[bernd5]

do you want to merge it or should I change something?

[jmarolf]

[jmarolf]

Thanks @bernd5! I'll go ahead and merge this in