Guide pratique pour créer un fournisseur de UI Automation Client-Side (proxy)

Cette rubrique contient un exemple de code qui montre comment implémenter un fournisseur Microsoft UI Automation côté client ou proxy.

• Exemple 1 : Énumération de la table de fabrique de proxy
• Exemple 2 : Implémentation d’un proxy simple pour les contrôles de bouton
• Rubriques connexes

Exemple 1 : Énumération de la table de fabrique de proxy

L’exemple de code suivant énumère les entrées dans la table de fabrique de proxy et affiche le nom de classe du contrôle pris en charge. Pour les proxys qui ne sont pas fournis avec le système d’exploitation, le nom de l’image s’affiche.

HRESULT GetProxyTable()
{
    IUIAutomationProxyFactoryMapping* pMap;
    IUIAutomationProxyFactoryEntry* pEntry;
    UINT count;
    BSTR className;
    BSTR imageName;

    HRESULT hr = g_pAutomation->get_ProxyFactoryMapping(&pMap);
    if (SUCCEEDED(hr))
    {
        if (SUCCEEDED(pMap->get_Count(&count)))
        {
            for (UINT x = 0; x < count; x++)
            {
                if (SUCCEEDED(pMap->GetEntry(x, &pEntry)))
                {
                    pEntry->get_ClassName(&className);
                    if (className)
                    {
                        std::wcout << className << L"\t";
                        SysFreeString(className);
                    }
                    if (SUCCEEDED(pEntry->get_ImageName(&imageName)))
                    {
                        if (imageName)
                        {
                            std::wcout << imageName;
                            SysFreeString(imageName);
                        }
                        std::wcout << L"\n";
                    }
                }
                pEntry->Release();
            }
        }
        pMap->Release();
    }

    return hr;
}

Exemple 2 : Implémentation d’un proxy simple pour les contrôles de bouton

L’exemple de code suivant implémente un proxy simple pour les contrôles qui ont le nom de classe « Button » et ajoute une entrée pour le proxy à la table de fabrique de proxy. Cet exemple utilise la boîte de dialogue Police du Bloc-notes pour illustrer le proxy.

// Registers a proxy for controls with the class name "BUTTON" and
// demonstrates it on the Font dialog of Notepad (which should be
// open when running this code).
#include "stdafx.h"
#include <stdio.h>
#include <tchar.h>

#include <windows.h>
#include <UIAutomation.h>

template <class T> void SafeRelease(T **ppT)
{
    if (*ppT)
    {
        (*ppT)->Release();
        *ppT = NULL;
    }
}

// A simple proxy for the proxy factory to create.
class ReallySimpleProxy : public IRawElementProviderSimple
{
public:
    ReallySimpleProxy(HWND hwnd):_refCount(1), _hWnd(hwnd) { }
    virtual ~ReallySimpleProxy() {}

    // IUnknown methods.
    IFACEMETHODIMP_(ULONG) AddRef() 
    { 
        return InterlockedIncrement(&_refCount);
    }
    IFACEMETHODIMP_(ULONG) Release()
    {
        long val = InterlockedDecrement(&_refCount);
        if(val == 0)
        {
            delete this;
        }
        return val;
    }

    IFACEMETHODIMP QueryInterface(REFIID riid, void** ppInterface)
    {
        if(riid == __uuidof(IUnknown))
            *ppInterface =(IUnknown*)((IRawElementProviderSimple*)this);
        else if(riid == __uuidof(IRawElementProviderSimple))
            *ppInterface =(IRawElementProviderSimple*)this;
        else
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }

        ((IUnknown*)(*ppInterface))->AddRef();
        return S_OK;
    }

    // IRawElementProviderSimple methods.
    IFACEMETHODIMP get_ProviderOptions(ProviderOptions * pRetVal)
    {
        *pRetVal = ProviderOptions_ClientSideProvider;
        return S_OK;
    }

    IFACEMETHODIMP GetPatternProvider(PATTERNID patternId, IUnknown ** pRetVal)
    {
        *pRetVal = NULL;
        return S_OK;
    }

    IFACEMETHODIMP GetPropertyValue(PROPERTYID propertyId, VARIANT * pRetVal)
    {
        pRetVal->vt = VT_EMPTY;

        // A String value to test
        if(propertyId == UIA_NamePropertyId)
        {
            pRetVal->vt = VT_BSTR;
            pRetVal->bstrVal = SysAllocString( L"ReallySimpleProxy Control" );
        }

        // Provider Id
        if(propertyId == UIA_ProviderDescriptionPropertyId)
        {
            pRetVal->vt = VT_BSTR;
            pRetVal->bstrVal = SysAllocString( L"Sample: ReallySimpleProxy" );
        }

        return S_OK;
    }

    IFACEMETHODIMP get_HostRawElementProvider(
        IRawElementProviderSimple ** pRetVal)
    {
        return UiaHostProviderFromHwnd(_hWnd, pRetVal); 
    }

private:
    ULONG _refCount;

    HWND _hWnd; // Window handle for this object.
};

// A simple proxy factory that creates a simple proxy.
class SimpleProxyFactory : public IUIAutomationProxyFactory
{
public:
    SimpleProxyFactory():_refCount(1) {}
    virtual ~SimpleProxyFactory() {}

    // IUnknown methods.
    IFACEMETHODIMP_(ULONG) AddRef() 
    { 
        return InterlockedIncrement(&_refCount);
    }
    IFACEMETHODIMP_(ULONG) Release()
    {
        long val = InterlockedDecrement(&_refCount);
        if(val == 0)
        {
            delete this;
        }
        return val;
    }

    IFACEMETHODIMP QueryInterface(REFIID riid, void** ppInterface)
    {
        if(riid == __uuidof(IUnknown))
            *ppInterface =(IUnknown*)((IUIAutomationProxyFactory*)this);
        else if(riid == __uuidof(IUIAutomationProxyFactory))
            *ppInterface =(IUIAutomationProxyFactory*)this;
        else
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }

        ((IUnknown*)(*ppInterface))->AddRef();
        return S_OK;
    }

    // IUIAutomationProxyFactory methods.
    IFACEMETHODIMP CreateProvider (UIA_HWND hwnd, LONG idObject, LONG idChild,
        IRawElementProviderSimple **ppRetVal )
    {
        *ppRetVal = new ReallySimpleProxy((HWND)hwnd);
        return S_OK;
    }

    IFACEMETHODIMP get_ProxyFactoryId ( BSTR *pRetVal )
    {
        *pRetVal = SysAllocString(L"Simple Proxy Factory");
        return S_OK;
    }

private:
    ULONG _refCount;
};


HRESULT CheckElement(IUIAutomation *uia, HWND hwnd)
{
    IUIAutomationElement * buttonEl = NULL;
    BSTR name = NULL;
    BSTR providerDescription = NULL;

    wprintf( L"Getting AutomationElement for the button...\n" );
    HRESULT hr = uia->ElementFromHandle(hwnd, &buttonEl);
    if (FAILED(hr))
        goto cleanup;
    if (buttonEl == NULL)
    {
        hr = E_FAIL;
        goto cleanup;
    }

    hr = buttonEl->get_CurrentName(&name);
    if (FAILED(hr))
        goto cleanup;

    hr = buttonEl->get_CurrentProviderDescription(&providerDescription);
    if (FAILED(hr))
        goto cleanup;

    wprintf( L"Got Element:\n  %s\n  %s\n\n", name, providerDescription);
cleanup:
    SysFreeString(providerDescription);
    SysFreeString(name);
    SafeRelease(&buttonEl);

    return hr;
}


int _tmain(int argc, _TCHAR* argv[])
{
    IUIAutomation * uia = NULL;
    IUIAutomationProxyFactoryMapping * proxyMapping = NULL;
    IUIAutomationProxyFactoryEntry * simpleEntry = NULL;
    IUIAutomationProxyFactory *simpleFactory = NULL;
    BSTR bstrClassName = NULL;

    wprintf( L"Initializing COM...\n" );
    HRESULT hr = CoInitializeEx( NULL, COINIT_APARTMENTTHREADED );
    if (FAILED(hr))
        goto cleanup;

    wprintf( L"CoCreating Automation Object...\n" );
    hr = CoCreateInstance(__uuidof(CUIAutomation), NULL, CLSCTX_INPROC_SERVER,
        __uuidof(IUIAutomation), (void **)&uia);
    if (FAILED(hr))
        goto cleanup;


    wprintf( L"Finding Notepad Font Window...\n" );
    HWND fontHwnd = FindWindow(NULL,L"Font");
    if (fontHwnd == NULL)
        goto cleanup;

    wprintf( L"Finding the OK button in Font Window...\n" );
    HWND buttonHwnd = FindWindowEx(fontHwnd, NULL, L"BUTTON", L"OK");
    if (buttonHwnd == NULL)
        goto cleanup;

    wprintf( L"Checking Name and Provider Description without our Proxy:\n" );
    CheckElement(uia, buttonHwnd);

    wprintf( L"Getting the Proxy Factory Mapping Object...\n" );
    hr = uia->get_ProxyFactoryMapping(&proxyMapping);
    if (FAILED(hr))
        goto cleanup;
    if (proxyMapping == NULL)
        goto cleanup;

    wprintf( L"Creating the Proxy Factory...\n" );
    simpleFactory = new SimpleProxyFactory();
    if (simpleFactory == NULL)
        goto cleanup;

    wprintf( L"Creating the Proxy Factory Entry...\n" );
    hr = uia->CreateProxyFactoryEntry(simpleFactory, &simpleEntry);
    if (FAILED(hr))
        goto cleanup;
   bstrClassName = SysAllocString(L"BUTTON");
    if (bstrClassName == NULL)
        goto cleanup;

    // Match HWNDs with Button class name.
    hr = simpleEntry->put_ClassName(bstrClassName);   
    if (FAILED(hr))
        goto cleanup;

    // Match any process ImageName.
    hr = simpleEntry->put_ImageName(NULL);            
    if (FAILED(hr))
        goto cleanup;

    // Do not allow substring matching.
    hr = simpleEntry->put_AllowSubstringMatch(FALSE); 
    if (FAILED(hr))
        goto cleanup;

    // Enter it into the mapping.
    hr = proxyMapping->InsertEntry(0, simpleEntry);
    if (FAILED(hr))
        goto cleanup;

    wprintf( L"Checking Name and Provider Description with our Proxy:\n" );
    CheckElement(uia, buttonHwnd);

cleanup:

    SafeRelease(&simpleEntry);
    SafeRelease(&simpleFactory);
    SafeRelease(&proxyMapping);
    SafeRelease(&uia);
    SysFreeString(bstrClassName);
    CoUninitialize();

    return 0;
}

Rubriques connexes

Conceptuel

Implémentation d’un fournisseur de Client-Side UI Automation

Rubriques de procédures pour les fournisseurs de UI Automation