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c#linqdynamic-linq
Muhammad Waqas
Muhammad Waqas

Reputation: 95

ParseLambda method throws an exception

I am trying to use ParseLambda method available in System.Linq.Dynamic library. When I execute the following simple example,

using Microsoft.Data.SqlClient;
using Microsoft.EntityFrameworkCore;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Linq.Dynamic;
using System.Linq.Expressions;

namespace DynamicLINQDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            ParameterExpression x = Expression.Parameter(typeof(int), "x");
            ParameterExpression y = Expression.Parameter(typeof(int), "y");
            LambdaExpression e = System.Linq.Dynamic.DynamicExpression.ParseLambda(new ParameterExpression[] { x, y }, null, "(x + y) * 2");
        }
    }
}

it throws the following exception.

System.TypeInitializationException: 'The type initializer for 'System.Linq.Dynamic.ExpressionParser' threw an exception.

Any idea what I am doing wrong?

Upvotes: 0

Views: 802

Answers (1)

Stef Heyenrath
Stef Heyenrath

Reputation: 9830

When using System.Linq.Dynamic.Core, this works:

ParameterExpression x = Expression.Parameter(typeof(int), "x");
ParameterExpression y = Expression.Parameter(typeof(int), "y");
LambdaExpression e = DynamicExpressionParser.ParseLambda(new [] { x, y }, null, "(x + y) * 2");

var c = e.Compile();
var result = c.DynamicInvoke(1, 2);
Console.WriteLine(result);

Upvotes: 2

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