c# - How do I format code selection and maintain leading trivia with Roslyn? -

i want format code modified roslyn. modifying code inside method. don't want reformat entire file. original formatting looks following:

mynamespace {     class codebasictests     {         int operationorder_0()         {             int = 20;             int b = 10;             int sum = + b;             return (int) sum;         }     } } 

after format body of method, gets aligned border, not method signature.

mynamespace {     class codebasictests     { int operationorder_0() {     int = 20;     int b = 10;     int c = 30; //new instruction     int sum = + b + c;     return (int) sum; }      } } 

i have tried following inside method visitor (csharpsyntaxrewriter):

methoddeclarationsyntax method = visited method node; updatedmethod = method.replacenode(method.body, newbody); updatedmethod = updatedmethod.normalizewhitespace().withtriviafrom(method); return updatedmethod; 

or selecting method body

newbody = (blocksyntax) formatter.format(oldbody, texts, visualstudiosolutionhandler.workspace); 

i have tried work text spans of formatter, don't manage make work @ at all.

i don't want/know write visitor insert right tab every element in newbody because statements insert more complex, , use autoformatting feature updated method only.

i don't know hot keep original method indentation.

replace trivia current trivia list new trivia inserted in place.

here's example of extension method created add newlines annotated nodes.

public static tnode addnewlinetoannotated<tnode>(this tnode node, string annotationkind)     tnode : csharpsyntaxnode =>     node.replacenodes(node.getannotatednodes(annotationkind), (_, n) =>         n.withleadingtrivia(n.getleadingtrivia()             .insert(0, syntaxtree.elasticendofline(environment.newline))         )     ); 

getting leading trivia gives syntaxtrivialist , can add(), insert() or otherwise modify trivia list give new trivia list.