Implementing a Custom LINQ Provider in C# - working with 'NotSupportedException'
I'm following best practices but I'm maintaining legacy code that I'm attempting to set up I'm trying to implement a custom LINQ provider in C#... My goal is to translate LINQ queries into a specific query language for my application. However, I'm running into a `NotSupportedException` when executing the queries. This is the code I'm working with: ```csharp public class MyQueryable<T> : IOrderedQueryable<T> { public MyQueryable(IQueryProvider provider, Expression expression) { Provider = provider; Expression = expression; } public Expression Expression { get; } public IQueryProvider Provider { get; } public Type ElementType => typeof(T); public IEnumerator<T> GetEnumerator() { return Provider.Execute<IEnumerable<T>>(Expression).GetEnumerator(); } IEnumerator IEnumerable.GetEnumerator() { return GetEnumerator(); } } public class MyQueryProvider : IQueryProvider { public IQueryable CreateQuery(Expression expression) { return new MyQueryable<T>(this, expression); } public IQueryable<TElement> CreateQuery<TElement>(Expression expression) { return new MyQueryable<TElement>(this, expression); } public object Execute(Expression expression) { // Custom execution logic // Example of translating the expression to a query language throw new NotImplementedException(); } public TResult Execute<TResult>(Expression expression) { // In this method, I am working with the exception throw new NotSupportedException("This operation is not supported."); } } ``` I've made sure that the `Execute` method is correctly set up, but I'm not sure why it's failing with `NotSupportedException`. I also tried calling `ToList()` on my `MyQueryable` instance which led to the same behavior. Additionally, I attempted to debug the execution flow, but the exception is thrown at runtime without a clear indication of which part of the expression is causing the scenario. Is there a specific part of the LINQ query execution that I might be missing, or is there a common pitfall when implementing a custom LINQ provider? Any suggestions for debugging this would be greatly appreciated! Any help would be greatly appreciated! The project is a CLI tool built with C#. What am I doing wrong? Any ideas how to fix this? My team is using C# for this CLI tool. What's the correct way to implement this?