// C# Eval Expression

// Doc: https://eval-expression.net/options

​

// @nuget: Z.Expressions.Eval

​

/*

## DynamicMemberNames

​

The DynamicMemberNames option lets you when compiling or executing an expression using an ExpandoObject as a parameter, retrieve all member names that we assume will be a member of the ExpandoObject. For example, suppose the `CustomerID` is returning from the member names list, in that case, the library expects the ExpandoObject will have a property and a value for this `CustomerID` to be executed correctly. By default, the DynamicMemberNames value is null.

​

In this example, we will first compile an expression and then, by looking at the `context.DynamicMemberNames` see which member names the library expects the `ExpandoObject` contains. In the second example, we will try to execute an expression that fails and check in the catch section which member names were expecting to be provided by the `ExpandoObject`.

​

​

See more: https://eval-expression.net/options

*/

​

using System;

using System.Collections.Generic;

using System.Dynamic;

using Z.Expressions;

​

public class Program

{

    public static void Main()

    {

        // Global Context: EvalManager.DefaultContext.DynamicMemberNames

        var context = new EvalContext();

        // required to allow to get member from the compile multiple from `Customer` and `ExpandoObject`

        context.IncludeMemberFromAllParameters = true;

        // compile example

        {

            var c1 = context.Compile<Func<Customer, ExpandoObject, bool>>("FirstName == 'C# Eval' && FullName == 'Test' && CreatedDate > #1981-04-13#");    

            FiddleHelper.WriteTable("1 - Expected ExpandoObject members:", context.DynamicMemberNames);

        }

​

        // execute example

        {

            try

            {

                var customer = new Customer();

                customer.FirstName = "C# Eval";

                customer.LastName = "Expression";

​

                dynamic expando = new ExpandoObject();

                expando.FullName = "ZZZ Projects";

​

                var fail = context.Execute<bool>("FirstName == 'C# Eval' && FullName == 'Test' && CreatedDate > #1981-04-13#", customer, expando);

            }

            catch(Exception ex)

            {       

                Console.WriteLine("2 - Exception: " + ex.Message);

                FiddleHelper.WriteTable("3 - Expected ExpandoObject members:", context.DynamicMemberNames);

            }

        }

    }

    public class Customer

    {

        public string FirstName;

        public string LastName;

    }

}