当我在Microsoft Docs上进行ML.DOTNET练习时，发现了一个关于CS0029的错误。完整代码如下：

using System;using System.IO;using Microsoft.ML;using System.Collections.Generic;using Microsoft.ML.TimeSeries;namespace ProductSalesAnomalyDetection{    class Program    {        static readonly string _dataPath = Path.Combine(Environment.CurrentDirectory, "Data", "phone-calls.csv");        static void Main(string[] args)        {            MLContext mlContext = new MLContext();            IDataView dataView = mlContext.Data.LoadFromTextFile<PhoneCallsData>(path: _dataPath, hasHeader: true, separatorChar: ',');            int period = DetectPeriod(mlContext, dataView);            DetectAnomaly(mlContext, dataView, period);        }        static void DetectPeriod(MLContext mlContext, IDataView phoneCalls)        {            int period = mlContext.AnomalyDetection.DetectSeasonality(phoneCalls, nameof(PhoneCallsData.value));            Console.WriteLine("Period of the series is: {0}.", period);        }        static void DetectAnomaly(MLContext mlContext, IDataView phoneCalls, int period)        {            var options = new SrCnnEntireAnomalyDetectorOptions()            {                Threshold = 0.3,                Sensitivity = 64.0,                DetectMode = SrCnnDetectMode.AnomalyAndMargin,                Period = period,            };            var outputDataView = mlContext.AnomalyDetection.DetectEntireAnomalyBySrCnn(phoneCalls, nameof(PhoneCallsPrediction.Prediction), nameof(PhoneCallsData.value), options);            var predictions = mlContext.Data.CreateEnumerable<PhoneCallsPrediction>(                outputDataView, reuseRowObject: false);            Console.WriteLine("Index\tData\tAnomaly\tAnomalyScore\tMag\tExpectedValue\tBoundaryUnit\tUpperBoundary\tLowerBoundary");            var index = 0;            foreach (var p in predictions)            {                if (p.Prediction[0] == 1)                {                    Console.WriteLine("{0},{1},{2},{3},{4}  <-- alert is on, detecte anomaly", index,                        p.Prediction[0], p.Prediction[3], p.Prediction[5], p.Prediction[6]);                }                else                {                    Console.WriteLine("{0},{1},{2},{3},{4}", index,                        p.Prediction[0], p.Prediction[3], p.Prediction[5], p.Prediction[6]);                }                ++index;            }            Console.WriteLine("");        }    }}

错误出现在Main方法中：

int period = DetectPeriod(mlContext, dataView);

错误信息是无法将类型’void’隐式转换为’int’。

我只是按照提供的代码进行操作，但看起来代码中有一些错误。可能是我把错误的代码放错了位置，但我严格按照他们的指示操作。如果您能告诉我JAVA和C#中将类型’void’隐式转换为’int’的区别，我将非常感激。谢谢

回答：

static void DetectPeriod(MLContext mlContext, IDataView phoneCalls)表示DetectPeriod()不返回任何值。而您试图将这个不存在的返回值赋给int period。

您需要将定义更改为返回int，然后实际return一个int值。

static int DetectPeriod(MLContext mlContext, IDataView phoneCalls)  {      int period = mlContext.AnomalyDetection.DetectSeasonality(phoneCalls, nameof(PhoneCallsData.value));      Console.WriteLine("Period of the series is: {0}.", period);      return period;  }