c# - 无法加载文件或程序集“System.Threading.Tasks.Extensions，版本=4.2.0.1”

Question

我正在尝试用 C# 编写 PowerShellCmdlet。它是一个用于进行 REST API 调用的 PowerShell 命令。这是代码重要功能的片段 -

    [Cmdlet(VerbsCommon.Get, "MXL3Firewall")]
    [OutputType(typeof(MXFirewallRule))]

    public class GetMXL3FirewallCommand : PSCmdlet
    {
        [Parameter(
            Mandatory = true,
            Position = 0,
            ValueFromPipeline = true,
            ValueFromPipelineByPropertyName = true)]
        public string Token { get; set; }

        [Parameter(
            Mandatory = true,
            Position = 1,
            ValueFromPipeline = true,
            ValueFromPipelineByPropertyName = true)]
        public string NetId { get; set; } 

        private static async Task<IList<MXFirewallRule>> GetFWRules(string Token, string NetId)
        {
            using (HttpClient client = new HttpClient())
            {
                client.DefaultRequestHeaders.Accept.Clear();
                client.DefaultRequestHeaders.Accept.Add(
                    new MediaTypeWithQualityHeaderValue("application/json"));
                client.DefaultRequestHeaders.Add("X-Cisco-Meraki-API-Key", Token);

                // Created the request header above

                var streamTask = client.GetStreamAsync($"https://api.meraki.com/api/v0/networks/{NetId}/l3FirewallRules");

                // converting the serialized JSON response into a C# object
                return await JsonSerializer.DeserializeAsync<IList<MXFirewallRule>>(await streamTask);               
            }
        }

        private static IList<MXFirewallRule> ProcessRecordAsync(string Token, string NetId)
        {
            var task = GetFWRules(Token, NetId);
            task.Wait();
            return task.Result;
        }
        protected override void ProcessRecord()
        {
            WriteVerbose("Entering Get Firewall Rules Call");
            var list = ProcessRecordAsync(Token, NetId);
            WriteObject(list, true);
        }
    } 

我收到以下错误 -

Get-MXL3Firewall : Could not load file or assembly 'System.Threading.Tasks.Extensions, Version=4.2.0.1,
Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file
specified.
At line:1 char:1
+ Get-MXL3Firewall -Token $token -NetId $netid
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Get-MXL3Firewall], FileNotFoundException
    + FullyQualifiedErrorId : System.IO.FileNotFoundException,RestToPSCommand.GetMXL3FirewallCommand

在(.csproj)中我有以下行 -

    <PackageReference Include="System.Threading.Tasks.Extensions" Version="4.5.4" />

我尝试按照所述更新 Nuget 包 here ，但这并没有帮助。 我该如何修复这个错误？

Answer 1

有可能发生的情况是其他一些引用正在尝试访问版本 4.2.0.1。 System.Threading.Tasks.Extensions 的。这被称为 DLL Hell，通常很难修复。如果是这种情况，您将必须查看引用并尝试找出哪个引用引用了 System.Threading.Tasks.Extensions 版本 4.2.0.1。

您可以尝试更新您的 NuGet 包。或许可以解决问题。

祝你好运!!!