从Powershell发送WM_COPYDATA消息，指针问题

Question

我正在尝试将控制消息从powershell发送到mpc-hc。Mpc 的 API 利用WM_COPYDATA消息。 以下是我到目前为止的情况，在看了这里，这里和这里之后：

Add-Type @"
using System;
using System.Runtime.InteropServices;
public class Messages {
[DllImport("user32.dll", CharSet = CharSet.Auto)]
public static extern IntPtr SendMessage(IntPtr hWnd, int Msg, int wParam, ref IntPtr lParam);
}
public struct COPYDATASTRUCT
{
public IntPtr dwData;    // Any value the sender chooses.  Perhaps its main window handle?
public int cbData;       // The count of bytes in the message.
public IntPtr lpData;    // The address of the message.
}
"@
$WM_COPYDATA = 0x004A;
$CMD_OSDSHOWMESSAGE = 0xA0005000
$MpcWindow1 = Start-Process -PassThru -FilePath "C:Program Files (x86)K-Lite Codec PackMPC-HC64mpc-hc64.exe" -ArgumentList "/new"
$MpcMessage = "hello"
$cds = New-Object COPYDATASTRUCT
$cds.dwData = $CMD_OSDSHOWMESSAGE
$cds.cbData = $MpcMessage.Length
$cds.lpData = $MpcMessage[0]     #without [0] throws an exception
[Messages]::SendMessage($MpcWindow1.MainWindowHandle, $WM_COPYDATA, (Get-Process powershell).MainWindowHandle, [ref]$cds[0])

执行它给了我：

Exception calling "SendMessage" with "4" argument(s): "Cannot convert the "COPYDATASTRUCT" value of type
"COPYDATASTRUCT" to type "System.IntPtr"."
At C:UsersPetersburg SDAVideosdevwm_copydata.ps1:27 char:1
+ [Messages]::SendMessage($MpcWindow1.MainWindowHandle, $WM_COPYDATA, (Get-Process ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [], MethodInvocationException
+ FullyQualifiedErrorId : PSInvalidCastException

我不确定 $MpcMessage[0] 是否正确，但仅使用变量就可以让我得到这个(除了上述内容(

Exception setting "lpData": "Cannot convert the "hello" value of type "System.String" to type "System.IntPtr"."
At C:UsersPetersburg SDAVideosdevwm_copydata.ps1:25 char:1
+ $cds.lpData = $MpcMessage     #throws an exception
+ ~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [], SetValueInvocationException
+ FullyQualifiedErrorId : ExceptionWhenSetting

将其更改为 [ref]$MpcMessage得到

Exception setting "lpData": "Cannot convert the "System.Management.Automation.PSReference`1[System.String]" value of
type "System.Management.Automation.PSReference`1[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral,
PublicKeyToken=b77a5c561934e089]]" to type "System.IntPtr"."
At C:UsersPetersburg SDAVideosdevwm_copydata.ps1:25 char:1
+ $cds.lpData = [ref]$MpcMessage     #throws an exception
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo          : NotSpecified: (:) [], SetValueInvocationException
+ FullyQualifiedErrorId : ExceptionWhenSetting

诚然，我没有经常使用powershell，但翻译代码被证明是非常困难的。

Answer 1

您必须使用 marshal 类将结构封送到指针。 例：

$StructPointerSize = [System.Runtime.InteropServices.Marshal]::SizeOf($CDS)
$StructPointer = [System.Runtime.InteropServices.Marshal]::AllocHGlobal($StructPointerSize)
[System.Runtime.InteropServices.Marshal]::StructureToPtr($CDS,$StructPointer,$true

这将分配一些内存，然后将结构复制到此内存块。 在此之后，指向结构的指针将位于 $StructPointer 变量中。

恢复暂停视频的完整示例(使用反射创建类型(：

$Domain = [System.AppDomain]::CurrentDomain
$AssemblyName = [System.Reflection.AssemblyName]::new('Messages')
$Assembly = $Domain.DefineDynamicAssembly($AssemblyName,'Run')
$ModuleBuilder = $Assembly.DefineDynamicModule('Messages')
# Define the struct (source : https://msdn.microsoft.com/en-us/library/windows/desktop/ms649010(v=vs.85).aspx)
$StructAttributes = 'AutoLayout, AnsiClass, Class, Public, SequentialLayout, BeforeFieldInit'
$COPYDATASTRUCT = $ModuleBuilder.DefineType('COPYDATASTRUCT',$StructAttributes)
$COPYDATASTRUCT.DefineField('dwData',[int],'Public')
$COPYDATASTRUCT.DefineField('cbData',[Uint32],'Public')
$COPYDATASTRUCT.DefineField('lpData',[System.IntPtr],'Public')
$COPYDATASTRUCT.CreateType()
# Define the class that will hold the PInvoke method
$MessageClass = $ModuleBuilder.DefineType('Messages','Public')
# Define the PInvoke Method
$SendMessage = $MessageClass.DefinePInvokeMethod(
'SendMessageW',
'User32.dll',
@('Public','Static','PinvokeImpl'),
[System.Reflection.CallingConventions]::Standard,
[System.IntPtr],
@([System.IntPtr],[Uint32],[System.IntPtr],[System.IntPtr]),
[System.Runtime.InteropServices.CallingConvention]::Winapi,
[System.Runtime.InteropServices.CharSet]::Unicode
)
$SendMessage.DefineParameter(1,'In','hWnd')
$SendMessage.DefineParameter(2,'In','Msg')
$SendMessage.DefineParameter(3,'In','wParam')
$SendMessage.DefineParameter(4,'In','lParam')

$SendMessage.SetImplementationFlags($SendMessage.GetMethodImplementationFlags() -bor [System.Reflection.MethodImplAttributes]::PreserveSig)
$MessageClass.CreateType()
$WM_COPYDATA = 0x004A;
$CMD_PLAY = 0xA0000004
$CurrentHandle = [System.Diagnostics.Process]::GetCurrentProcess().MainWindowHandle
$Arguments = '/Slave' + " " + $CurrentHandle.ToString()
Start-Process -FilePath 'C:Program FilesMPC-HCmpc-hc64.exe' -ArgumentList $Arguments
$CDS = [COPYDATASTRUCT]::new()
$CDS.dwData = $CMD_PLAY
$CDS.lpData = [System.IntPtr]::Zero
$CDS.cbData = 0
$StructPointerSize = [System.Runtime.InteropServices.Marshal]::SizeOf($CDS)
$StructPointer = [System.Runtime.InteropServices.Marshal]::AllocHGlobal($StructPointerSize)
[System.Runtime.InteropServices.Marshal]::StructureToPtr($CDS,$StructPointer,$true)
$p = (Get-Process mpc-hc64).MainWindowHandle
[messages]::SendMessageW($p,$WM_COPYDATA,0,$StructPointer)