c# - Conditional Group and Select in LINQ with type conversion -

i know there bunch of questions out there on still cannot work due type conversion (i think).

i have list of custom class , group either months (mt) or quarters (qr) depending on user choice. works fine. however, have request allow grouping q413 , rest of 2013 in months. mt , qr strings. quartpos double , equals 4 if q4 in quarters , rest in months.

here have:

list<myclass> results = classlist   .groupby(a => new {                  a.rg,                 a.tar,                 a.mt = ((double.parse(a.qr) < quartpos) ? a.mt : 0),                 a.qr })   .select(g => new myclass {                 rg = g.select(a => a.rg).first(),                tar = g.select(a => a.tar).first(),                yr = g.select(a => a.yr).first(),                qr = g.select(a => a.qr).first(),                mt = g.select(a => a.mt).first(),                pp = g.average(a => double.parse(a.pp)),                pi = g.sum(a => double.parse(a.pi)),                cp = g.average(a => double.parse(a.cp)),                ci = g.sum(a => double.parse(a.ci)),                = g.sum(a => double.parse(a.it)),                = g.sum(a => double.parse(a.to)),                cnt = g.select(a => a.dt).distinct().count(),                pdvol = g.sum(a => (double.parse(a.pp) <= 1)                                    ? 0                                    : (double.parse(a.pi) / double.parse(a.pp))) })   .tolist(); 

this throws 2 errors:

1. string int type conversion - since mt string : 0 int

2. invalid anonymous type member declaration.

i m aware have use same syntax in select make sure quarters selected if grouped quarters , months if grouped mounths also.

definition of class:

public class myclass {     public string yr;     public string qr;     public string mt;     public string cw;     public string tar;     public string rg;     public double pp;     public double pi;     public double cp;     public double ci;     public double it;     public double to;     public double pd;     public double cd;     public double fp;     public double fi;     public double fd;     public int cnt;     public double pdmw;     public double pdvol;  } 

classlist class variables strings - straight csv import.

my question how can group month (mt) conditionally?

a.mt = ((double.parse(a.qr) < quartpos) ? a.mt : 0) 

you can't create anonymous types this. take @ syntax in documentation.

either want:

a.mt 

or

propertyname = ((double.parse(a.qr) < quartpos) ? a.mt : 0) 

in line.