借助microsoft.management.infrastructure命名空间在C＃中使用WMI创建快照

Question

我正在尝试在C＃中创建一个方法，其中创建了Hyper-V中虚拟机的快照。

我正在使用新的microsoft.management.infrastructure命名空间而不是system.management.instrumentation。

我最大的问题是创建CIM_VirtualSystemSettingData对象，我将其作为引用参数传递给invoke方法。我不知道如何设置InstanceId属性。因为我总是得到错误消息：无法处理Targetobject因为key-attribute为null（从德语翻译）。当我设置它manualy（我可能不应该这样做）我得到一个错误代码：

WBEM_E_INVALID_METHOD_PARAMETERS
2147749935 (0x8004102F)
Parameters provided for the method are not valid.

我也不确定virtualsystemsetting对象是否是唯一的问题。但错误信息是如此模糊，以至于我不知道还有什么地方可以开始调试。

我的代码到目前为止：

 // id is the Virtual machine i want the snapshot to be made of
 public String CreateSnapshot(string id) { 

        string cimNamespace = @"root\virtualization\v2";
        string cimMethodName = "CreateSnapshot";
        string cimClassName = "Msvm_VirtualSystemSnapshotService";

        CimInstance QuellComputer = Session.QueryInstances(@"ROOT\virtualization\v2", "WQL", $"SELECT * FROM CIM_Computersystem").Skip(2).FirstOrDefault();// WHERE Name={id}

        CimClass systemSettingClass = Session.GetClass(cimNamespace, "CIM_VirtualSystemSettingData");
        CimInstance systemSettingInstance = new CimInstance(systemSettingClass);            
        systemSettingInstance.CimInstanceProperties["SnapshotDataRoot"].Value = @"C:\Users\SnapshotsTemp";                        
        systemSettingInstance.CimInstanceProperties["ElementName"].Value = @"SnapshotNo1";
        systemSettingInstance.CimInstanceProperties["VirtualSystemType"].Value = 5;          

        CimMethodParametersCollection cimMethodParameters = new CimMethodParametersCollection();
        CimMethodParameter cimMethodParameter1 = CimMethodParameter.Create("AffectedSystem", QuellComputer, CimType.Reference, CimFlags.In);
        CimMethodParameter cimMethodParameter2 = CimMethodParameter.Create("SnapshotSettings", "", CimType.String, CimFlags.In);
        CimMethodParameter cimMethodParameter4 = CimMethodParameter.Create("ResultingSnapshot", generateid, CimType.Reference, CimFlags.In);
        CimMethodParameter cimMethodParameter3 = CimMethodParameter.Create("SnapshotType", 2, CimType.UInt16, CimFlags.In);            
        cimMethodParameters.Add(cimMethodParameter1);
        cimMethodParameters.Add(cimMethodParameter4);
        cimMethodParameters.Add(cimMethodParameter2);
        cimMethodParameters.Add(cimMethodParameter3);

        CimMethodResult result = Session.InvokeMethod(cimNamespace, cimClassName, cimMethodName, cimMethodParameters);
}

这是Microsoft对Msvm_VirtualSystemSnapshotService类的WMI方法描述

uint32 CreateSnapshot(
  [in]      CIM_ComputerSystem           REF AffectedSystem,
  [in]      string                           SnapshotSettings,
  [in]      uint16                           SnapshotType,
  [in, out] CIM_VirtualSystemSettingData REF ResultingSnapshot,
  [out]     CIM_ConcreteJob              REF Job

提前致谢。

Answer 1

您需要创建相应类型的空CimInstance，并使用CimInstanceProperties集合的Add方法添加所需的键属性。然后使用CimSession类的GetInstance方法检索填充了所有数据的完整CimInstance。每个类都在线记录了所需的关键属性，但我遇到了文档不完整的情况。为了避免允许自动生成的文档分散您的注意力，我建议您在目标的WMI类实例上查看__RELPATH属性。这将提供键值对。

在PowerShell中：

gwmi -Namespace root\virtualization\v2 -Class Msvm_VirtualSystemSnapshotService | select __relpath | fl

要得到...

__RELPATH : Msvm_VirtualSystemSnapshotService.CreationClassName="Msvm_VirtualSystemSnapsho
            tService",Name="vssnapsvc",SystemCreationClassName="Msvm_ComputerSystem",Syste
            mName="MYHOSTNAME"

这意味着在C＃中，你需要这样做：

// Using Microsoft.Management.Infrastructure
private const string _namespace = @"root\virtualization\v2";
private const string _hypervHost = "MYHOSTNAME";

using (var cimSession = CimSession.Create(_hyperVHost))
{
    // Create generic instance with no instance data
    var keyInstance = new CimInstance("Msvm_VirtualSystemSnapshotService");
    // Attach key CimProperties
    keyInstance.CimInstanceProperties.Add(CimProperty.Create("CreationClassName", "Msvm_VirtualSystemSnapshotService", CimFlags.Key));
    keyInstance.CimInstanceProperties.Add(CimProperty.Create("SystemCreationClassName", "Msvm_ComputerSystem", CimFlags.Key));
    keyInstance.CimInstanceProperties.Add(CimProperty.Create("Name", "vssnapsvc", CimFlags.Key));
    keyInstance.CimInstanceProperties.Add(CimProperty.Create("SystemName", _hyperVHost, CimFlags.Key));
    // Retrieve the object
    snapShotService = cimSession.GetInstance(_namespace, keyInstance);
}