// C# Eval Expression

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

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// @nuget: Z.Expressions.Eval

​

/*

## AutoAddMissingTypes

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The AutoAddMissingTypes option lets you get or set if the library should try to automatically find and add missing types when an expression cannot compile due to missing types. You can specify which assembly the missing types should look for through the RegisterAutoAddMissingTypeAssembly method, otherwise the library will search over all domain assemblies. By default, the AutoAddMissingTypes value is `false` for performance and side impact reasons.

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In this example, we will try to evaluate an expression the first time without the `AutoAddMissingTypes` option, which will fail, and then try again but with the option this time.

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> NOTE: We also added two examples of our built-in smart resolution allowing our library to discover types from the parameter and return type without using the `AutoAddMissingTypes` option.

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

*/

​

using System;

using System.Collections.Generic;

using Z.Expressions;

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public class Program

{

    public static void Main()

    {

        // Global Context: EvalManager.DefaultContext.AutoAddMissingTypes = true;

        var context = new EvalContext();

        try

        {

            var fail = (Entity)context.Execute("return new Entity() { EntityID = 13 }");

        }

        catch(Exception ex)

        {

            Console.WriteLine("1 - Exception: " + ex.Message);

        }

        // Using the `AutoAddMissingTypes`

        {

            context.AutoAddMissingTypes = true;

            var entity = (Entity)context.Execute("return new Entity() { EntityID = 13 }");

​

            Console.WriteLine("2 - EntityID: " + entity.EntityID);

        }

        // NOTE: The library has a built-in smart resolution when a type is already passing in a parameter or as a return type

        {

            var context2 = new EvalContext();

            var entity3 = (Entity)context2.Execute("return new Entity() { EntityID = 13 }", new { AnotherEntity = new Entity() });

            Console.WriteLine("3 - EntityID: " + entity3.EntityID);

            var entity4 = context2.Execute<Entity>("return new Entity() { EntityID = 13 }");

            Console.WriteLine("3 - EntityID: " + entity4.EntityID);

        }

    }

    public class Entity

    {

        public int EntityID { get; set; }

    }

}

​

​