PressKey method of the Msvm_Keyboard class

Simulates a key press. When successful the key will be in the down state.

Syntax

uint32 PressKey(
  [in] uint32 keyCode
);

Parameters

keyCode [in]

Type: uint32

The virtual-key code of the key to press. For the list for virtual-key codes, see Virtual-Key Codes.

Return value

Type: uint32

A return value of zero indicates success. A nonzero value indicates a failure to modify the key state.

Completed with No Error (0)

Method Parameters Checked - Job Started (4096)

Failed (32768)

Access Denied (32769)

Not Supported (32770)

Status is unknown (32771)

Timeout (32772)

Invalid parameter (32773)

System is in used (32774)

Invalid state for this operation (32775)

Incorrect data type (32776)

System is not available (32777)

Out of memory (32778)

Remarks

The PressKey method maps references to the VK_MENU (18), VK_CONTROL (17), and VK_SHIFT (16) to VK_LMENU (164), VK_LCONTROL (162), and VK_LSHIFT (160), respectively, because the VK_MENU, VK_CONTROL, and VK_SHIFT virtual key codes do not represent real keys on a keyboard.

Access to the Msvm_Keyboard class might be restricted by UAC Filtering. For more information, see User Account Control and WMI.

Examples

The following C# sample simulates a key press. The referenced utilities can be found in Common Utilities for the Virtualization Samples.

using System;
using System.Management;

namespace HyperVSamples
{
    class PressKeyClass
    {
        static ManagementObject GetComputerKeyboard(ManagementObject vm)
        {
            ManagementObjectCollection keyboardCollection = vm.GetRelated
            (
                "Msvm_Keyboard",
                "Msvm_SystemDevice",
                null,
                null,
                "PartComponent",
                "GroupComponent",
                false,
                null
            );

            ManagementObject keyboard = null;

            foreach (ManagementObject instance in keyboardCollection)
            {
                keyboard = instance;
                break;
            }

            return keyboard;
        }

        static void PressKey(string vmName, int keyCode)
        {
            ManagementScope scope = new ManagementScope(@"root\virtualization", null);
            ManagementObject vm = Utility.GetTargetComputer(vmName, scope);
            ManagementObject keyboard = GetComputerKeyboard(vm);

            ManagementBaseObject inParams = keyboard.GetMethodParameters("PressKey");

            inParams["keyCode"] = keyCode;

            ManagementBaseObject outParams = keyboard.InvokeMethod("PressKey", inParams, null);

            if ((UInt16)outParams["ReturnValue"] == ReturnCode.Completed)
            {
                string.Format("Key {0} was pressed on {1}", keyCode, vm["ElementName"]);
            }
            else
            {
                string.Format("Unable to press key {0}' on {1}", keyCode, vm["ElementName"]);
            }

            inParams.Dispose();
            outParams.Dispose();
            keyboard.Dispose();
            vm.Dispose();
        }

        static void Main(string[] args)
        {
            if (args != null && args.Length != 2)
            {
                Console.WriteLine("Usage: PressKey vmName keyCode");
                return;
            }
            string vmName = args[0];
            int keyCode = int.Parse(args[1]);
            PressKey(args[0], keyCode);
        }

    }
}

The following VBScript sample simulates a key press.

option explicit 

dim objWMIService
dim fileSystem
const wmiSuccessful = 0

Main()

'-----------------------------------------------------------------
' Main routine
'-----------------------------------------------------------------
Sub Main()
    
    dim computer, objArgs, vmName, computerSystem, keycode, keyboard
    
    set fileSystem = Wscript.CreateObject("Scripting.FileSystemObject")

    computer = "."
    set objWMIService = GetObject("winmgmts:\\" & computer & "\root\virtualization")

    set objArgs = WScript.Arguments
    if WScript.Arguments.Count = 2 then
       vmName= objArgs.Unnamed.Item(0)
       keycode = objArgs.Unnamed.Item(1)
    else
       WScript.Echo "usage: cscript PressKey.vbs vmName keycode"
       WScript.Quit
    end if
    
    set computerSystem = GetComputerSystem(vmName)
    set keyboard = GetComputerKeyboard(computerSystem)

    if PressKey(keyboard, keycode) then

        WriteLog "Done"
        WScript.Quit(0)
    else
        WriteLog "PressKey failed"
        WScript.Quit(1)
    end if

End Sub

'-----------------------------------------------------------------
' Retrieve Msvm_VirtualComputerSystem from base on its ElementName
' 
'-----------------------------------------------------------------
Function GetComputerSystem(vmElementName)
    dim query
    On Error Resume Next
    query = Format1("select * from Msvm_ComputerSystem where ElementName = '{0}'", vmElementName)
    set GetComputerSystem = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
        WScript.Quit(1)
    end if
End Function


'-----------------------------------------------------------------
' Retrieve Msvm_Keyboard from given computer system
' 
'-----------------------------------------------------------------
Function GetComputerKeyboard(computerSystem)
    dim query
    On Error Resume Next
    query = Format1("ASSOCIATORS OF {{0}} WHERE resultClass = Msvm_Keyboard", computerSystem.Path_.Path)
    set GetComputerKeyboard = objWMIService.ExecQuery(query).ItemIndex(0)
    if (Err.Number <> 0) then
        WriteLog Format1("Err.Number: {0}", Err.Number)
        WriteLog Format1("Err.Description:{0}",Err.Description)
        WScript.Quit(1)
    end if
End Function

'-----------------------------------------------------------------
' Press the key with the given key code on the given keyboard
'-----------------------------------------------------------------
Function PressKey(keyboard, keyCode)
    WriteLog Format2("PressKey({0}, {1})", keyboard.ElementName, keyCode)
    
    dim objInParam, objOutParams
    
    PressKey = false
    set objInParam = keyboard.Methods_("PressKey").InParameters.SpawnInstance_()
    objInParam.keyCode = keyCode

    set objOutParams = keyboard.ExecMethod_("PressKey", objInParam)

    if objOutParams.ReturnValue = wmiSuccessful then
        WriteLog Format2("The key with code '{0}' is typed on {1}.", keyCode, keyboard.ElementName)
        PressKey = true
    end if

End Function

'-----------------------------------------------------------------
' Create the console log files.
'-----------------------------------------------------------------
Sub WriteLog(line)
    dim fileStream
    set fileStream = fileSystem.OpenTextFile(".\PressKey.log", 8, true)
    WScript.Echo line
    fileStream.WriteLine line
    fileStream.Close

End Sub


'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format2(myString, arg0, arg1)
    Format2 = Format1(myString, arg0)
    Format2 = Replace(Format2, "{1}", arg1)
End Function

'------------------------------------------------------------------------------
' The string formatting functions to avoid string concatenation.
'------------------------------------------------------------------------------
Function Format1(myString, arg0)
    Format1 = Replace(myString, "{0}", arg0)
End Function

Requirements

See also

Msvm_Keyboard

Virtual-Key Codes