c# - Assign variable to Expression<Func<TSource, bool>> -

using net 4.5.1

have following class respondent:

namespace whatever {   public class respondent {     public int x { get; set; }     public int y { get; set; }      public static expression<func<respondent, bool>> comparexy(int value) {       return x => ((x.x * 100) + x.y) > value;     }   } } 

lets want pass body of lamdba around. getting by:

... function ... type membertype = typeof(<this class>).assembly.gettype("whatever.respondent");  object[] parameters = new object[] { <populate integer value> };  var expr = membertype   .getmethod(memberfunctionname, bindingflags.public | bindingflags.static)   .invoke(null, parameters) lambdaexpression;  return expr.body 

problem variable x (i.e. respondent) not defined. example, functional expression comparexy might included in larger expression tree derives series of predicates (i.e. standing comparisons, literals, functions, etc):

...function returning expression<func<respondent, bool>>... expr = predicates.aggregate(   (prev, next) => new , { operands = new expr[] { prev, next}  } );  expression composition = together.getexpression(context);  <-- here resolving comparexy return expression.lambda(composition, new parameterexpression[] { context }); 

basically, body of lambda returned comparexy has have variable/parameter x set respondent type.

edit, getting following error:

 {"variable 'x' of type 'charting.models.respondent' referenced scope '',   not defined"} 

question how define variable x body of lambda?

i'm not entirely sure there's question in there, think answered it:

the body of lambdaexpression doesn't include parameters. in expr.parameters. if need re-use body of lambda, you'll need recreate it.

alternatively, can pass lambda in entirety, call use invokeexpression invoke lambda.

edit: answer question, must pass parameters along body of expression. parameter used must reference equivalent what's in expr.parameters. can't substitute newly created parameterexpression.