C#调用PowerShell操作打印机端口遇PSInvalidCastException问题求助

针对基于.NET Framework 4.6.2、使用Microsoft.PowerShell.5.1.ReferenceAssemblies.1.0.0中System.Management.Automation.dll操作打印机端口时出现的枚举字符串转System.Type失败的PSInvalidCastException异常，提供以下几个解决思路：

• 手动处理枚举类型转换
  避免依赖PowerShell自动类型映射，在获取输出结果后，显式对涉及枚举的字段进行解析：

  using (var powerShell = Create())
  {
      powerShell.AddCommand("Get-PrinterPort").AddParameter("Name", "somePortName");
      var output = powerShell.Invoke();
      
      foreach (var portItem in output)
      {
          if (portItem.Properties["RenderingMode"]?.Value != null)
          {
              string modeStr = portItem.Properties["RenderingMode"].Value.ToString();
              var renderingMode = Enum.Parse(typeof(Microsoft.PowerShell.Cmdletization.GeneratedTypes.Printer.RenderingModeEnum), modeStr);
              // 后续使用转换后的枚举值即可
          }
      }
  }
  

• 调整PowerShell输出格式
  通过PowerShell命令筛选或转换输出，减少复杂类型的自动转换压力。比如只选择需要的字段，让返回结果以基础类型呈现：

  using (var powerShell = Create())
  {
      powerShell.AddScript(@"Get-PrinterPort -Name 'somePortName' | Select-Object Name, PortNumber, RenderingMode");
      var output = powerShell.Invoke();
  }
  

• 配置程序集重定向
  由于受限于System.Runtime 4.1.2版本，可能存在依赖版本冲突。在应用的app.config中添加程序集重定向，确保依赖版本统一：

  <runtime>
      <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
          <dependentAssembly>
              <assemblyIdentity name="System.Runtime" publicKeyToken="b03f5f7f11d50a3a" culture="neutral" />
              <bindingRedirect oldVersion="0.0.0.0-4.1.2.0" newVersion="4.1.2.0" />
          </dependentAssembly>
          <dependentAssembly>
              <assemblyIdentity name="System.Management.Automation" publicKeyToken="31bf3856ad364e35" culture="neutral" />
              <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="1.0.0.0" />
          </dependentAssembly>
      </assemblyBinding>
  </runtime>
  

• 注册自定义类型转换器
  创建自定义的PowerShell类型转换器，处理枚举字符串到System.Type的转换逻辑，并注册到Runspace中：

  var runspaceConfig = RunspaceConfiguration.Create();
  // 注册自定义转换器
  runspaceConfig.TypeTable.AddType(new TypeConverterAttribute(typeof(string), typeof(Type))
  {
      ConverterType = typeof(CustomEnumTypeConverter)
  });
  
  using (var runspace = RunspaceFactory.CreateRunspace(runspaceConfig))
  {
      runspace.Open();
      using (var powerShell = PowerShell.Create())
      {
          powerShell.Runspace = runspace;
          powerShell.AddCommand("Get-PrinterPort").AddParameter("Name", "somePortName");
          var output = powerShell.Invoke();
      }
  }
  
  // 自定义转换器实现
  public class CustomEnumTypeConverter : PSTypeConverter
  {
      public override bool CanConvertFrom(object sourceValue, Type destinationType)
      {
          return sourceValue is string && destinationType == typeof(Type);
      }
  
      public override object ConvertFrom(object sourceValue, Type destinationType, IFormatProvider formatProvider, bool ignoreCase)
      {
          if (sourceValue is string enumFullName && enumFullName.Contains("Microsoft.PowerShell.Cmdletization.GeneratedTypes.Printer."))
          {
              // 尝试加载目标枚举类型
              return Type.GetType(enumFullName, false);
          }
          return base.ConvertFrom(sourceValue, destinationType, formatProvider, ignoreCase);
      }
  
      public override bool CanConvertTo(object sourceValue, Type destinationType) => false;
      public override object ConvertTo(object sourceValue, Type destinationType, IFormatProvider formatProvider, bool ignoreCase) => null;
  }
  

内容的提问来源于stack exchange，提问作者piort