expression

问题 This problem occurs in both NHibernate 2 and 3. I have a Class A that has a member set of class B. Querying the classes directly executes nicely. But when I pass one of the expressions involving class B into a method I get the following error: System.ArgumentException: Object of type 'System.Linq.Expressions.ConstantExpression' cannot be converted to type 'System.Linq.Expressions.LambdaExpression'. As far as I can see I am passing the exact same expression into the Any() method. But for some

问题 I'm looking for a JAVA library to parse & evaluate expression. I searched and tried some libraries like Apache's JEXL and Jeval, but they are not exactly what I need. My requirements: Support all value types (i.e. int,double,boolean,String, etc.) Support all known mathematical & logical operators (+,-,*,<,<=,etc.) Support variables (without any special notation - for example in Jeval variable a should be written like #{a} - not good enough for me) Support custom functions - with type

问题 For the past few hours I have been trying to find the difference between the 3, not just the difference, I also have been trying to find out which are sort of synonymous, MDN calls all declarations "statements", so I presume that is true. However, none of the articles and SO questions I read provided me with a cheatsheet of sorts to distinguish between the 3 (or the 2, expressions vs statements). Something I have noticed with statements is that they all somehow involve a special JavaScript

问题 For the past few hours I have been trying to find the difference between the 3, not just the difference, I also have been trying to find out which are sort of synonymous, MDN calls all declarations "statements", so I presume that is true. However, none of the articles and SO questions I read provided me with a cheatsheet of sorts to distinguish between the 3 (or the 2, expressions vs statements). Something I have noticed with statements is that they all somehow involve a special JavaScript

问题 I have an oracle table like this: create table tms_transaction_tbl ( trans_id number primary key, location_id number, trans_date date, resource_id number, ts_id number, max_value number, booked_units number default 0, remaining number default (select max_value-booked_units), booked number not null , user_id number, trans_time timestamp ); as you can see I tried to set default value of remaining to (max_value-booked_units) remainging number default (select max_value-booked_units), but it gives

问题 I have an oracle table like this: create table tms_transaction_tbl ( trans_id number primary key, location_id number, trans_date date, resource_id number, ts_id number, max_value number, booked_units number default 0, remaining number default (select max_value-booked_units), booked number not null , user_id number, trans_time timestamp ); as you can see I tried to set default value of remaining to (max_value-booked_units) remainging number default (select max_value-booked_units), but it gives

问题 I want to use let expressions, but the following code doesn't work: true ? (let x=1, let y=2, x+y) : (let x=3, let y=4, x-y); // SyntaxError How am I supposed to do this? 回答1: Unfortunately, Javascript lacks lisp-style let expressions. However, since there are default parameters and arrow functions we can mimic them: const let_ = f => f(); console.log( true ? let_((x = 1, y = 2) => x + y) : let_((x = 3, y = 4) => x - y) // 3 ); To be honest, this is a bit tedious and the code is pretty

问题 I am currently using a formula to calculate a variable, which looks like: =(Fields!MontantInitialRegime.Value/Fields!MontantInitial.Value)*Fields!SoldeFacture.Value It works well, except for the cases where both numerator and denominator equal zero. I've done some research and I've tried to solve it by using the formula below, which doesn't work. =IIF(Fields!MontantInitialRegime.Value = 0, Fields!SoldeFacture.Value, Fields!MontantInitialRegime.Value / IIF(Fields!MontantInitial.Value = 0,

问题 I'm trying to build an arbitrary precision calculator. I represent numbers in linked lists (one node is a single digit), and I want to store them in a stack. However, I can't seem to figure out how to break the mathematical expression received as a string apart while keeping the right mathematical operations order. For example, if the inserted expression is 6*8-2+8-8*9/4 , I'll represent numbers as linked lists and insert them into a stack, and insert the operators into a different stack, and

问题 I have an extension generic method public static void AddError<TModel>( this ModelStateDictionary modelState, Expression<Func<TModel, object>> expression, string resourceKey, string defaultValue) { // How can I get a reference to TModel object from expression here? } I need to get the reference to TModel object from expression. This method called by the following code: ModelState.AddError<AccountLogOnModel>( x => x.Login, "resourceKey", "defaultValue") 回答1: You cannot get to the TModel object