c# - 无法使用 C# 函数从 Json 文件中读取多个值

Question

我正在尝试执行一个函数，该函数返回我在 Json 文件中获得的值的总和。
所以为此我创建了一个模型来反序列化 Json 文件，它是这样的:
使用 System.Collections.Generic;

namespace ServerMonitoringApi.Controllers.CpuUsage.Model
{
    public class Metric
    {
        public string __name__ { get; set; }
        public string core { get; set; }
        public string instance { get; set; }
        public string job { get; set; }
    }

    public class Result
    {
        public Metric metric { get; set; }
        public IList<object> value { get; set; }
    }

    public class Data
    {
        public string resultType { get; set; }
        public IList<Result> result { get; set; }
    }

    public class CpuUsageResponse
    {
        public string status { get; set; }
        public Data data { get; set; }
    }
}

它适用于反序列化等。我已经测试过了。

在我的 Controller 中，我有这个函数返回总和并导致问题:

[HttpGet("Number/{instance}&{port}")]
public async Task<double> GetNumCpuUsagePerInstance(string instance, string port)
{
    string perInstanceLink = MetricApiLink + "{instance=\"" + instance + ":" + port + "\"}";
    string idleModeLink = MetricApiLink +
        "{mode=\"idle\",instance=\"" + instance + ":" + port + "\"}";
    dynamic dataGetAll;
    dynamic dataGetIdle;
    using (var httpClient = new HttpClient())
    {
        using (var response = await httpClient
            .GetAsync(perInstanceLink))
        {
            string apiResponse = await response.Content.ReadAsStringAsync();
            dataGetAll = JsonConvert.DeserializeObject<CpuUsageResponse>(apiResponse);
        }
    }
    using (var httpClient = new HttpClient())
    {
        using (var response = await httpClient
            .GetAsync(idleModeLink))
        {
            string apiResponse = await response.Content.ReadAsStringAsync();
            dataGetIdle = JsonConvert.DeserializeObject<CpuUsageResponse>(apiResponse);
        }
    }

    double sum1 = 0;
    double sum2 = 0;
    NumberFormatInfo provider = new NumberFormatInfo();
    provider.NumberGroupSeparator = ".";

    foreach(CpuUsageResponse x in dataGetAll)
    {
        sum1 += Convert.ToDouble(x.data.result[1].value[1], provider);
    }

    return sum1;
}

我已经测试了它们工作正常的每个功能，但是当我尝试执行“Foreach”时它不起作用并给我这个错误消息:

RuntimeBinderException: Cannot implicitly convert type 'ServerMonitoringApi.Controllers.CpuUsage.Model.CpuUsageResponse' to 'System.Collections.IEnumerable'. An explicit conversion exists (are you missing a cast?) And say that the error is in the line 123 which is:

    NumberFormatInfo provider = new NumberFormatInfo();
    provider.NumberGroupSeparator = ".";

    /*here(line 123)->*/ foreach(CpuUsageResponse x in dataGetAll)
    {
        sum1 += Convert.ToDouble(dataGetAll.data.result[1].value[1], provider);
    }

我的 Json 文件是这样的:

{
    "status": "success",
    "data": {
        "resultType": "vector",
        "result": [
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,0",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "95595.25"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,1",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "103647.703125"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,2",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "94185.015625"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,3",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "102109.203125"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,4",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "96709.59375"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,5",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "102046.5625"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,6",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "98963.453125"
                ]
            },
            {
                "metric": {
                    "__name__": "wmi_cpu_time_total",
                    "core": "0,7",
                    "instance": "192.168.1.101:9182",
                    "job": "Server-monitoring-Api"
                },
                "value": [
                    1583873150.877,
                    "89011.53125"
                ]
            }
        ]
    }
}

我正在尝试对索引为 1 的值求和，即 value[1]并归还

Answer 1

您的 JSON 由包含 data.result [] 的单个根对象组成。大批:

{
   "status":"success",
   "data":{
      "resultType":"vector",
      "result":[/* Results */]
   }
}

每个结果如下所示:

{
    "metric": {
        "__name__": "wmi_cpu_time_total",
        "core": "0,0",
        "instance": "192.168.1.101:9182",
        "job": "Server-monitoring-Api"
    },
    "value": [
        1583851813.666,
        "79186.65625"
    ]
}

因此，像您在此处尝试执行的操作一样，遍历最外层的 JSON 容器

foreach(CpuUsageResponse x in dataGetAll)
{
    sum1 += Convert.ToDouble(x.data.result[1].value[1], provider);
}

真没意思。如果最外面的 JSON 容器是数组，那将是一件明智的事情。

相反，如果你想把所有 data.result[*].value[1] 加起来值转换为 double 结果，您可以按如下方式进行:

CpuUsageResponse dataGetAll;

// Download the apiResponse JSON string (code omitted)

dataGetAll = JsonConvert.DeserializeObject<CpuUsageResponse>(apiResponse);

var sum = dataGetAll.data.result
    .Select(r => r.value[1])
    .Select(s => Convert.ToDouble(s, NumberFormatInfo.InvariantInfo))
    .Sum();

演示 fiddle here .

笔记:

做 不是 声明 dataGetAll如 dynamic .通过这样做，您可以消除对代码正确性的所有编译时检查，并将其替换为运行时错误，例如 RuntimeBinderException您的问题中显示的异常。既然你创建了一个 c# 数据模型，你应该使用它，如果你有，你会收到一个更清晰的编译错误:

CpuUsageResponse dataGetAll;

dataGetAll = JsonConvert.DeserializeObject<CpuUsageResponse>(apiResponse);

double sum1 = 0;
NumberFormatInfo provider = new NumberFormatInfo();
provider.NumberGroupSeparator = ".";

//Compilation error (line 63, col 43): foreach statement cannot operate on variables of type 'CpuUsageResponse' because 'CpuUsageResponse' does not contain a public instance definition for 'GetEnumerator'
foreach(CpuUsageResponse x in dataGetAll)
{
    sum1 += Convert.ToDouble(x.data.result[1].value[1], provider);
}   

演示 fiddle #2 here .

见 When should one use dynamic keyword in c# 4.0? , Is the use of dynamic considered a bad practice?和 What is the 'dynamic' type in C# 4.0 used for?有关何时使用和不使用的进一步讨论，dynamic .

您的 CpuUsageResponse对于提供的 JSON，数据模型看起来是正确的。

而不是构建您自己的自定义 NumberFormatInfo ，您可以使用 NumberFormatInfo.InvariantInfo .