// C# Eval Expression

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

​

// @nuget: Z.Expressions.Eval

​

/*

### The parameters

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You have multiple different ways how you can pass your parameters. Furthermore, there is no best way to pass parameters as everything depends on your scenario and preference:

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1. `Eval.Execute<TResult>(string code)`: https://dotnetfiddle.net/4vOu2H

2. `Eval.Execute<TResult>(string code, object parameters)`: https://dotnetfiddle.net/wdLPTE

3. `Eval.Execute<TResult>(string code, params object[] parameters)`: https://dotnetfiddle.net/Q0gWZ3

​

---

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3 - In the case of `Eval.Execute<TResult>(string code, params object[] parameters)`, you can pass your parameter through the `params object[]`. You can learn more about [params here](https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/params)

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3a - Since parameters are not named (our library doesn't know your variable, property, or field name), you need to use positions such as `{0}` and `{1}` in the expression as you usually do with, for example, [string.Format](https://learn.microsoft.com/en-us/dotnet/api/system.string.format):

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3b - In addition, unlike section 2 (`Eval.Execute<TResult>(string code, object parameters)`) that we have seen, you cannot use member names or key names directly by default unless you use the [IncludeMemberFromAllParameters option](/options#includememberfromallparameters)

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

*/

​

using System;

using System.Collections.Generic;

using Z.Expressions;

​

public class Program

{

    public static void Main()

    {

        // example 3a

        {

            var expression = "return new List<int>() { 1, 2, 3, 4, 5 }.Where(x => x > {0} && x < {1})";

            var list3a = Eval.Execute<List<int>>(expression, 1, 5);

​

            FiddleHelper.WriteTable(list3a);

        }

        // example 3b

        {

            var context = new EvalContext();

​

            // SET IncludeMemberFromAllParameters option

            context.IncludeMemberFromAllParameters = true;

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            var parameter1 = new Parameter1() { MinValue = 1 };

            var parameter2 = new Parameter2() { MaxValue = 5 };

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            var expression = "return new List<int>() { 1, 2, 3, 4, 5 }.Where(x => x > MinValue && x < MaxValue)";

            var list3b = context.Execute<List<int>>(expression, parameter1, parameter2);

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            FiddleHelper.WriteTable(list3b);

        }

    }

    public class Parameter1

    {

        public int MinValue { get; set; }

    }

    public class Parameter2

    {

        public int MaxValue { get; set; }

    }

}

​

​