// C# Eval Expression

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

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// @nuget: Z.Expressions.Eval

​

/*

## SafeMode

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The SafeMode option lets you get or set if only members and types registered can be used for the expression. In other words, you can safely execute user input in your environment by restricting him to use only what you allow. Make sure to read the [SafeMode](/safe-mode) documentation if you plan to use this option. By default, the SafeMode value is `false`.

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In this example, with the option `SafeMode = true`, we will unregister all our library's default members and try to evaluate a simple expression. The expression will fail, and we will show the message that the member is not supported in safe mode (the member is missing). Then we will add all methods of the `System.Math` class by using the `RegisterMember` method and successfully evaluate our expression this time.

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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.SafeMode = true;

​

        var context = new EvalContext();

        context.SafeMode = true;

        context.UnregisterAll();

        try

        {

            var fail = context.Execute("Math.Min(1, 2)");

            Console.WriteLine(fail);

        }

        catch(Exception ex)

        {

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

        }

        // try again by registering "System.Math" member

        context.RegisterMember(typeof(System.Math));

        var r2 = context.Execute("Math.Min(1, 2)");

        Console.WriteLine("2 - Result: " + r2);

    }

}

​

​