c# - How do I create a new root by adding and removing nodes retrieved from the old root? -

i creating code fix changes this:

if(obj myclass) {     var castedobj = obj myclass; } 

into this:

var castedobj = obj myclass; if(castedobj != null) { } 

this means have 3 things:

• change condition in if statement.
• move casting right above if statement.
• remove statement in body.

so far, attempts have stranded me @ getting @ 2 of these things work.

i believe problem occurs because have 2 syntax nodes on same level. such, making change 1 of them invalidates location of other one. or that. long story short: either manage copy variable assignment outside if statement, or manage change condition + remove variable assignment. never 3.

how solve this?

for measure, here code changes condition , removes assignment:

var newifstatement = ifstatement.removenode(                                    variabledeclaration,                                    syntaxremoveoptions.keepexteriortrivia); newifstatement = newifstatement.replacenode(newifstatement.condition, newcondition);  var ifparent = ifstatement.parent; var newparent = ifparent.replacenode(ifstatement, newifstatement); newparent = newparent.insertnodesbefore(                            newifstatement,                             new[] { variabledeclaration })                            .withadditionalannotations(formatter.annotation);  var newroot = root.replacenode(ifparent, newparent); 

have looked @ documenteditor class ? useful when dealing modifying syntax, when changes applied tree might cause invalidation problems. operations pretty same ones have defined, use documenteditor methods instead , see if helps. can't verify if solves problem atm, think solved similar problem me once in past. i'll test out later if can.

something it:

var editor = await documenteditor.createasync(document); editor.removenode(variabledeclaration); editor.replacenode(ifstatement.condition, newcondition); editor.insertbefore(ifstatement,       new[] { variabledeclaration.withadditionalannotations(formatter.annotation) });  var newdocument = editor.getchangeddocument();