IVMVirtualMachine::SetActivationValue method

Article
12/11/2020

[Windows Virtual PC is no longer available for use as of Windows 8. Instead, use the Hyper-V WMI provider (V2).]

Sets the value of the specified activation setting for this virtual machine.

Syntax

HRESULT SetActivationValue(
  [in] BSTR    activationKey,
  [in] VARIANT activationValue
);

Parameters

activationKey [in]: The key used to identify the activation value as stored in the "*.vmc" file.
activationValue [in]: The activation value. This value can be one of the following VARIANT types: VT_ARRAY|VT_UI1 (raw bytes), VT_BSTR (string), VT_UI4 (integer), or VT_BOOL (Boolean).

Return value

This method can return one of these values.

Return code/value	Description
S_OK 0	The operation was successful.
E_INVALIDARG 0x80000003	The activationKey parameter is NULL or empty, or the activationValue parameter is not a valid variant type.
VM_E_VM_UNKNOWN 0xA0040207	The configuration is unknown.
VM_E_PREF_NOT_FOUND 0xA0040300	The configuration has no valid activation.
DISP_E_EXCEPTION 0x80020009	An unexpected error has occurred.

Remarks

This method provides low-level access to any activation value. It can be used to set activation values for customer-defined keys. Be careful if you use this method to set system activation values, since no error checking is performed on the activation value. Also, some activation values cannot be changed while the virtual machine is running. When a virtual machine is started, a copy is made of its configuration values, which becomes its set of activation values. Activation values are maintained until the virtual machine is shut down or restarted. Note that Windows Virtual PC may only use the configuration to store values for certain keys, that is, the activation value may never be used.

Note

The virtual machine session must be running before any activation values can be changed.

Activation keys are stored internally in a hierarchical manner similar to the registry keys in Windows. To specify a specific subkey, a "key path" is constructed which specifies the various keys in a slash mark delimited format.

For example, to set the value of the "default_action" key located in the following key tree:

<settings>
    <undo_drives>
        <default_action type="integer">1</default_action>

The activationKey path string would be specified as follows:

"settings/undo_drives/default_action"

Requirements

Requirement	Value
Minimum supported client	Windows 7 [desktop apps only]
Minimum supported server	None supported
End of client support	Windows 7
Product	Windows Virtual PC
Header	VPCCOMInterfaces.h
IID	IID_IVMVirtualMachine is defined as f7092aa1-33ed-4f78-a59f-c00adfc2edd7