"'BaseClass' does not contain a constructor that takes 0 arguments." Partial C# / Protobuf class -

i have class mydatarow derive datarow, here code:

public partial class mydatarow : datarow {     internal mydatarow(datarowbuilder builder)         : base(builder)     {         // initialization of variables     } } 

the class partial , has no members because exists partially in proto file (members defined there, too).

trying build produces error cs1729: 'system.data.datarow' not contain constructor takes 0 arguments. i'm bit out of ideas, since i'm calling explicitly : base(builder).

what missing? :)

edit: upon request, here's proto-part:

message sampledatarow {     enum someenum     {         imavalue    = 1;         metoo       = 2;     }      // more enums...      optional double    _member1    = 30 [default = 0];     optional double    _member2    = 31 [default = 0];      // more members... } 

protocol buffers creates default constructor without arguments proto-part of partial class, leads error. matthew watson pointing out.

scrapping c#-half of class , instead working proto-definition alone viable solution in case.