CODEWITHSUNDEEP
c#roslyn
epitka
epitka

Reputation: 17627

How to add a property definition to existing type

If I want to add a new property to a type do I need to rebuild the whole type or is there a way to add property to existing type? Since one can only replace the nodes, do I have to replace the whole class declaration node? If so how would one do it?

Only way I have found to do this is dirty, and basically boils down to getting the source code of the type, finding the first open bracket, and inserting new source code for property, then parsing the resulting text and then replacing old class declaration node with a new one.

Something like this:

var toTypeSymbol =(TypeSymbol)compilation.GetTypeByMetadataName(propertyTypeInfo.ToString());

var toTypeDeclarationSyntax = (ClassDeclarationSyntax) toTypeSymbol.DeclaringSyntaxNodes.First();

var origToTypeCode = toTypeSymbol.DeclaringSyntaxNodes.First().ToFullString();

var idx = origToTypeCode.IndexOf("{")+1;

var newPropertyCode = String.Format(@" protected internal virtual {0} {0} {{get;set;}}",classSymbol.Name);

var newTypeCode = origToTypeCode.Insert(idx, newPropertyCode);

var newType = Syntax.ParseCompilationUnit(newTypeCode).NormalizeWhitespace();

var classDeclarationSyntax = newType.ChildNodes().OfType<ClassDeclarationSyntax>().First();

var temp = toTypeDeclarationSyntax.Parent.ReplaceNode(toTypeDeclarationSyntax,classDeclarationSyntax).NormalizeWhitespace();


Console.WriteLine(temp.ToFullString());

Upvotes: 1

Views: 117

Answers (1)

Kevin Pilch
Kevin Pilch

Reputation: 11605

You could take a look at the ImplementINotifyPropertyChanged sample that is included in the CTP. One of the things it does is add an event, and a method. The same strategy applies to properties.

Upvotes: 3

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