static Expression BuildExpr <T>(SimpleRule r, ParameterExpression param)
{
var left = MemberExpression.Property(param, r.Left);
var right = MemberExpression.Property(param, r.Right);
ExpressionType tBinary;
if (ExpressionType.TryParse(r.Operator, out tBinary))
{
var rightConstant = Expression.Constant(right);
return(Expression.MakeBinary(tBinary, left, rightConstant));
}
//else
//{
// var method = tProp.GetMethod(r.Operator);
// var tParam = method.GetParameters()[0].ParameterType;
// var right = Expression.Constant(r.Right);
// // use a method call, e.g. 'Contains'
// return Expression.Call(left, method, right);
//}
return(null);
}