Why can I use initializer syntax with readonly properties [duplicate]

Answer 1

The ReportingEmployeesIds = {2345, 432, 521} doesn't set the property. It is shorthand for calling Add(...) with each of the items. You can always Add, even for a readonly list property.

For it to be a set it would need to be:

ReportingEmployeesIds = new List {2345, 432, 521}

Instead, the line:

Manager m = new Manager {Name = "Dave", ReportingEmployeesIds = {2345, 432, 521} }

is essentially:

var m = new Manager();
m.Name = "Dave";
var tmp = m.ReportingEmployeesIds;
tmp.Add(2345);
tmp.Add(432);
tmp.Add(521);