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delphiwinapiwindows-10tablet-pc

How to detect if Windows 10 is in tablet mode with Delphi?

How would someone detect when a user enters tablet mode on a Windows 10 device with Delphi code?

Can someone show a code example for this?

I don't want to detect if the user has a tablet or not. I simply want to see whether they're in tablet mode or not. What would be the best way to do this?

Solution

  • I deleted the previous variant (based on [SO]: How can I detect when Windows 10 enters tablet mode in a Windows Forms application? (@CheeseLover's answer) (pointed out by @Remko's comment)) because it's a totally different scenario (doesn't have anything to do with Win running on desktop).

    I spent some time on [MS.DevBlogs]: Raymond - How can I detect whether my PC is in tablet mode? (pointed out in @RitaHan-MSFT's answer (+1)), and clearly, that's the way to go.

    I don't know how to "translate" the code into Delphi, as many years passed since I wrote significant amounts of code in it (but I'm sure it's possible), so I did the next best thing: wrote a C++ .dll (containing a modified / improved version of Raymond's code) that is called from Delphi.

    Note: VStudio is required to build the .dll, I used 2015 Community Edition, which is free and can be downloaded from [VStudio]: Visual Studio 2015 and other Products (you need an MS account though).

    dll.cpp:

    #include <wrl/client.h>
#include <windows.ui.viewmanagement.h>
#include <UIViewSettingsInterop.h>
#include <wrl/wrappers/corewrappers.h>


namespace WRL = Microsoft::WRL;
namespace VM = ABI::Windows::UI::ViewManagement;


class Backend {
public:
    static Backend &instance()
    {
        static Backend m_instance;
        return m_instance;
    }

    WRL::ComPtr<IUIViewSettingsInterop> interop() {return m_interop;}

private:
    Backend()
    {
        HRESULT res = CoInitializeEx(nullptr, COINIT_APARTMENTTHREADED);
        m_comInit = (res == S_OK) || (res == S_FALSE);
        if (m_comInit || (res == RPC_E_CHANGED_MODE)) {
            res = Windows::Foundation::GetActivationFactory(WRL::Wrappers::HStringReference(
                RuntimeClass_Windows_UI_ViewManagement_UIViewSettings).Get(), &m_interop);
        }
    }

    Backend(const Backend &other) = delete;
    Backend &operator =(const Backend &other) = delete;

    ~Backend()
    {
        if (m_interop) {m_interop.Reset();}
        if (m_comInit) {CoUninitialize();}
    }

    bool m_comInit = false;
    WRL::ComPtr<IUIViewSettingsInterop> m_interop = nullptr;
};


/*!
    Gets Tablet mode value.
    \param hwnd Window handle to get the mode for
    \returns:
         1 - Tablet mode ON
         0 - Tablet mode OFF
        -X - Error
*/
extern "C" __declspec(dllexport) int GetTabletMode(HWND hwnd)
{
    WRL::ComPtr<IUIViewSettingsInterop> interop = Backend::instance().interop();
    if (!interop) {
        return -3;
    }

    WRL::ComPtr<VM::IUIViewSettings> viewSettings;
    HRESULT res = interop->GetForWindow(hwnd != NULL ? hwnd : GetConsoleWindow(), IID_PPV_ARGS(&viewSettings));
    if (!viewSettings) {
        return -2;
    }

    VM::UserInteractionMode currentMode;
    res = viewSettings->get_UserInteractionMode(&currentMode);

    int ret = -1;
    switch (currentMode) {
        case VM::UserInteractionMode_Mouse: ret = 0; break;
        case VM::UserInteractionMode_Touch: ret = 1; break;
        default: ret = -1;
    }

    viewSettings.Reset();
    return ret;
}

    Below is the Delphi relevant code (only the unit, as the rest can easily be manufactured, and there's no point placing it all here).

    Unit0.pas:

    
unit Unit0;

interface

uses
    Forms, Dialogs, Controls, StdCtrls, Classes;


type
    TForm0 = class(TForm)
    CheckButton: TButton;
        procedure CheckButtonClick(Sender: TObject);
    private
        { Private declarations }
    public
        { Public declarations }
end;

var
    Form0: TForm0;


    function GetTabletMode(hwnd: THandle): Integer cdecl; external 'TabletUtils.dll';


implementation

{$R *.dfm}

procedure TForm0.CheckButtonClick(Sender: TObject);
var
    TabletModeStr: String;
begin
    case GetTabletMode(Self.Handle) of
        0 : TabletModeStr := 'OFF';
        1 : TabletModeStr := 'ON';
        else TabletModeStr := 'ERROR';
    end;
    MessageDlg('Tablet Mode: ' + TabletModeStr, mtInformation, [mbOK], 0);
end;

end.

    Output:

    
[cfati@CFATI-5510-0:e:\Work\Dev\StackOverflow\q056321591]> sopr.bat
### Set shorter prompt to better fit when pasted in StackOverflow (or other) pages ###

[prompt]> "c:\Install\x86\Microsoft\Visual Studio Community\2015\vc\vcvarsall.bat" x86

[prompt]> dir /b
App0.cfg
App0.dof
App0.dpr
App0.exe
App0.res
dll.cpp
other
Unit0.dcu
Unit0.ddp
Unit0.dfm
Unit0.pas

[prompt]> cl /nologo /DDLL /DNDEBUG /DUSRDLL /D_WINDOWS /MT dll.cpp  /link /NOLOGO /DLL /OUT:TabletUtils.dll ole32.lib runtimeobject.lib
dll.cpp
   Creating library TabletUtils.lib and object TabletUtils.exp

[prompt]> dir /b
App0.cfg
App0.dof
App0.dpr
App0.exe
App0.res
dll.cpp
dll.obj
other
TabletUtils.dll
TabletUtils.exp
TabletUtils.lib
Unit0.dcu
Unit0.ddp
Unit0.dfm
Unit0.pas

[prompt]> App0.exe

[prompt]>

    In the screenshot below, I ran the application:

    • On my laptop (Win 10) with Desktop mode (right side)

    • On a Win 10 VM with Tablet mode (left side). Note that I had to copy:

      • App0.exe

      • TabletUtils.dll

    Img0