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  1. C# Driver
  2. CSHARP-5027

LINQ3 does not allow cast to float

    • Type: Icon: Question Question
    • Resolution: Works as Designed
    • Priority: Icon: Unknown Unknown
    • None
    • Affects Version/s: 2.24.0
    • Component/s: LINQ3
    • None
    • Dotnet Drivers
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      1. What would you like to communicate to the user about this feature?
      2. Would you like the user to see examples of the syntax and/or executable code and its output?
      3. Which versions of the driver/connector does this apply to?

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      1. What would you like to communicate to the user about this feature? 2. Would you like the user to see examples of the syntax and/or executable code and its output? 3. Which versions of the driver/connector does this apply to?

      Summary

      Issues with LinqProvider.V3

      Driver Version: C# driver 2.24.0

      How to Reproduce

      var connectionString = "mongodb://localhost:27017";
      var setting = MongoClientSettings.FromConnectionString(connectionString);
      setting.LinqProvider = LinqProvider.V3;
      var mongoClient = new MongoClient(setting);
      
      var db = mongoClient.GetDatabase("test");
      var coll = db.GetCollection<CallRecord>("calls");
      
      var result = coll.AsQueryable()
          .Select(p => new {name= p.PhoneNumber,DurationInMinute = Math.Ceiling((float)p.Duration / 60) });
      
      var array = await result.ToListAsync();
      
      foreach (var record in array)
      {
          Console.WriteLine($"phone:{record.name},Duration:{record.DurationInMinute}");
      }
      
      public record CallRecord(string PhoneNumber,int Duration); 

      As shown in the code, if setting.LinqProvider = LinqProvider.V2 is set, it can run normally. However, if setting.LinqProvider = LinqProvider.V3 is set, the following error occurs:
       

      Unhandled exception. MongoDB.Driver.Linq.ExpressionNotSupportedException: Expression not supported: Convert(p.Duration, Single) because conversion to System.Single is not supported.
         at MongoDB.Driver.Linq.Linq3Implementation.Translators.ExpressionToAggregationExpressionTranslators.ConvertExpressionToAggregationExpressionTranslator.Translate(TranslationContext context, UnaryExpression expression)

       

            Assignee:
            james.kovacs@mongodb.com James Kovacs
            Reporter:
            gw2008@gmail.com p3 p3
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              Created:
              Updated:
              Resolved: