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Cómo implementar controladores de eventos

  • Artículo

Este tema contiene código de ejemplo que muestra cómo implementar interfaces que permiten a los clientes recibir y controlar eventos de Microsoft Automatización de la interfaz de usuario. Se describen los temas siguientes:

Controlar eventos de Automatización de la interfaz de usuario generales

El ejemplo de código siguiente es una aplicación de consola de Microsoft Windows que implementa un controlador de eventos Automatización de la interfaz de usuario para eventos de Automatización de la interfaz de usuario generales. En este ejemplo se controlan los eventos de creación y destrucción de información sobre herramientas y otras ventanas.

// Defines an event handler for general UI Automation events. It listens for
// tooltip and window creation and destruction events. 
#include <windows.h>
#include <stdio.h>
#include <UIAutomation.h>

class EventHandler:
    public IUIAutomationEventHandler
{
private:
    LONG _refCount;

public:
    int _eventCount;

    // Constructor.
    EventHandler(): _refCount(1), _eventCount(0) 
    {
    }

    // IUnknown methods.
    ULONG STDMETHODCALLTYPE AddRef() 
    {
        ULONG ret = InterlockedIncrement(&_refCount);
        return ret;
    }

    ULONG STDMETHODCALLTYPE Release() 
    {
        ULONG ret = InterlockedDecrement(&_refCount);
        if (ret == 0) 
        {
            delete this;
            return 0;
        }
        return ret;
    }

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppInterface) 
    {
        if (riid == __uuidof(IUnknown)) 
            *ppInterface=static_cast<IUIAutomationEventHandler*>(this);
        else if (riid == __uuidof(IUIAutomationEventHandler)) 
            *ppInterface=static_cast<IUIAutomationEventHandler*>(this);
        else 
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }
        this->AddRef();
        return S_OK;
    }

    // IUIAutomationEventHandler methods
    HRESULT STDMETHODCALLTYPE HandleAutomationEvent(IUIAutomationElement * pSender, EVENTID eventID)
    {
        _eventCount++;
        switch (eventID) 
        {
            case UIA_ToolTipOpenedEventId:
                wprintf(L">> Event ToolTipOpened Received! (count: %d)\n", _eventCount);
                break;
            case UIA_ToolTipClosedEventId:
                wprintf(L">> Event ToolTipClosed Received! (count: %d)\n", _eventCount);
                break;
            case UIA_Window_WindowOpenedEventId:
                wprintf(L">> Event WindowOpened Received! (count: %d)\n", _eventCount);
                break;
            case UIA_Window_WindowClosedEventId:
                wprintf(L">> Event WindowClosed Received! (count: %d)\n", _eventCount);
                break;
            default:
                wprintf(L">> Event (%d) Received! (count: %d)\n", eventID, _eventCount);
                break;
        }
        return S_OK;
    }
};

int main(int argc, char* argv[])
{
    HRESULT hr;
    int ret = 0;
    IUIAutomationElement* pTargetElement = NULL;
    EventHandler* pEHTemp = NULL;

    CoInitializeEx(NULL,COINIT_MULTITHREADED);
    IUIAutomation* pAutomation = NULL;
    hr = CoCreateInstance(__uuidof(CUIAutomation), NULL,CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation), (void**)&pAutomation);
    if(FAILED(hr) || pAutomation==NULL) 
    {
        ret = 1;
        goto cleanup;
    }
    // Use root element for listening to window and tooltip creation and destruction.
    hr = pAutomation->GetRootElement(&pTargetElement);
    if (FAILED(hr) || pTargetElement==NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    pEHTemp = new EventHandler();
    if (pEHTemp == NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Adding Event Handlers.\n");
    hr = pAutomation->AddAutomationEventHandler(UIA_ToolTipOpenedEventId, pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }
    hr = pAutomation->AddAutomationEventHandler(UIA_ToolTipClosedEventId, pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }
    hr = pAutomation->AddAutomationEventHandler(UIA_Window_WindowOpenedEventId, pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }
    hr = pAutomation->AddAutomationEventHandler(UIA_Window_WindowClosedEventId, pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Press any key to remove event handlers and exit\n");
    getchar();

    wprintf(L"-Removing Event Handlers.\n");

cleanup:
    // Remove event handlers, release resources, and terminate
    if (pAutomation != NULL) 
    {
        hr = pAutomation->RemoveAllEventHandlers();
        if (FAILED(hr))
            ret = 1;
        pAutomation->Release();
    }

    if (pEHTemp != NULL) 
        pEHTemp->Release();

    if (pTargetElement != NULL) 
        pTargetElement->Release();

    CoUninitialize();
    return ret;
}

Control de eventos de Focus-Changed

El ejemplo de código siguiente es una aplicación de consola de Windows que implementa un controlador para eventos de cambio de foco.

// Defines an event handler for focus changed events and starts
// listening to them.
#include <windows.h>
#include <stdio.h>
#include <UIAutomation.h>

class EventHandler:
    public IUIAutomationFocusChangedEventHandler
{
private:
    LONG _refCount;

public:
    int _eventCount;

    //Constructor.
    EventHandler(): _refCount(1), _eventCount(0) 
    {
    }

    //IUnknown methods.
    ULONG STDMETHODCALLTYPE AddRef() 
    {
        ULONG ret = InterlockedIncrement(&_refCount);
        return ret;
    }

    ULONG STDMETHODCALLTYPE Release() 
    {
        ULONG ret = InterlockedDecrement(&_refCount);
        if (ret == 0) 
        {
            delete this;
            return 0;
        }
        return ret;
    }

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppInterface) 
    {
        if (riid == __uuidof(IUnknown))
            *ppInterface = static_cast<IUIAutomationFocusChangedEventHandler*>(this);
        else if(riid == __uuidof(IUIAutomationFocusChangedEventHandler)) 
            *ppInterface=static_cast<IUIAutomationFocusChangedEventHandler*>(this);
        else 
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }
        this->AddRef();
        return S_OK;
    }

    // IUIAutomationFocusChangedEventHandler methods.
    HRESULT STDMETHODCALLTYPE HandleFocusChangedEvent(IUIAutomationElement * pSender) 
    {
        _eventCount++;
        wprintf(L">> FocusChangedEvent Received! (count: %d)\n", _eventCount);
        return S_OK;
    }
};

int main(int argc, char* argv[]) 
{
    HRESULT hr;
    int ret = 0;
    EventHandler* pEHTemp = NULL;

    CoInitializeEx(NULL,COINIT_MULTITHREADED);
    IUIAutomation* pAutomation = NULL;
    hr = CoCreateInstance(__uuidof(CUIAutomation), NULL,CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation), (void**)&pAutomation);
    if (FAILED(hr) || pAutomation == NULL)
    {
        ret = 1;
        goto cleanup;
    }

    pEHTemp = new EventHandler();
    if (pEHTemp == NULL)
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Adding Event Handlers.\n");
    hr = pAutomation->AddFocusChangedEventHandler(NULL, (IUIAutomationFocusChangedEventHandler*) pEHTemp); 
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Press any key to remove event handler and exit\n");
    getchar();

    wprintf(L"-Removing Event Handlers.\n");
    hr = pAutomation->RemoveFocusChangedEventHandler((IUIAutomationFocusChangedEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    // Release resources and terminate.
cleanup:
    if (pEHTemp != NULL) 
        pEHTemp->Release();

    if (pAutomation != NULL) 
        pAutomation->Release();

    CoUninitialize();
    return ret;
}

Control de eventos de Property-Changed

El ejemplo de código siguiente es una aplicación de consola de Windows que implementa un controlador para eventos modificados por propiedades.

// Defines an event handler for property-changed events, and listens for
// ToggleState property changes on the element specifies by the user.
#include <windows.h>
#include <stdio.h>
#include <UIAutomation.h>

class EventHandler:
    public IUIAutomationPropertyChangedEventHandler
{
private:
    LONG _refCount;

public:
    int _eventCount;

    //Constructor.
    EventHandler(): _refCount(1), _eventCount(0) 
    {
    }

    //IUnknown methods.
    ULONG STDMETHODCALLTYPE AddRef() 
    {
        ULONG ret = InterlockedIncrement(&_refCount);
        return ret;
    }

    ULONG STDMETHODCALLTYPE Release() 
    {
        ULONG ret = InterlockedDecrement(&_refCount);
        if (ret == 0) 
        {
            delete this;
            return 0;
        }
        return ret;
    }

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppInterface) 
    {
        if (riid == __uuidof(IUnknown))
            *ppInterface=static_cast<IUIAutomationPropertyChangedEventHandler*>(this);
        else if (riid == __uuidof(IUIAutomationPropertyChangedEventHandler)) 
            *ppInterface=static_cast<IUIAutomationPropertyChangedEventHandler*>(this);
        else 
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }
        this->AddRef();
        return S_OK;
    }

    // IUIAutomationPropertyChangedEventHandler methods.
    HRESULT STDMETHODCALLTYPE HandlePropertyChangedEvent(IUIAutomationElement* pSender, PROPERTYID propertyID, VARIANT newValue) 
    {
        _eventCount++;
        if (propertyID == UIA_ToggleToggleStatePropertyId) 
            wprintf(L">> Property ToggleState changed! ");
        else 
            wprintf(L">> Property (%d) changed! ", propertyID);

        if (newValue.vt == VT_I4) 
            wprintf(L"(0x%0.8x) ", newValue.lVal);

        wprintf(L"(count: %d)\n", _eventCount);
        return S_OK;
    }
};

int main(int argc, char* argv[]) 
{
    HRESULT hr;
    int ret = 0;
    IUIAutomationElement* pTargetElement = NULL;
    EventHandler* pEHTemp = NULL;

    CoInitializeEx(NULL,COINIT_MULTITHREADED);

    IUIAutomation* pAutomation = NULL;
    hr = CoCreateInstance(__uuidof(CUIAutomation), NULL, CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation), (void**)&pAutomation);
    if (FAILED(hr) || pAutomation==NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Use the mouse to point to the element you want to listen from.\n");
    Sleep(3000);

    // Make this application dots-per-inch (DPI) aware.
    SetProcessDPIAware();

    // Get mouse cursor position and get element from point.
    POINT pt;
    GetPhysicalCursorPos(&pt);
    hr = pAutomation->ElementFromPoint(pt, &pTargetElement);
    if (FAILED(hr) || pTargetElement==NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    pEHTemp = new EventHandler();
    if (pEHTemp == NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    PROPERTYID pPIDProperties[] = { UIA_ToggleToggleStatePropertyId };

    wprintf(L"-Adding Event Handler.\n");
    hr = pAutomation->AddPropertyChangedEventHandlerNativeArray(pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationPropertyChangedEventHandler*) pEHTemp, pPIDProperties, sizeof(pPIDProperties) / sizeof(pPIDProperties[0]));
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Press any key to remove event handler and exit\n");
    getchar();

    wprintf(L"-Removing Event Handler.\n");
    hr = pAutomation->RemovePropertyChangedEventHandler(pTargetElement, (IUIAutomationPropertyChangedEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    // Release resources and terminate.
cleanup:
    if (pEHTemp != NULL) 
        pEHTemp->Release();

    if (pTargetElement != NULL) 
        pTargetElement->Release();

    if (pAutomation != NULL) 
        pAutomation->Release();

    CoUninitialize();
    return ret;
}

Control de eventos de Structure-Changed

El ejemplo de código siguiente es una aplicación de consola de Windows que implementa un controlador para eventos modificados por la estructura.

// Defines an event handler for structure-changed events, and 
// listens for them on the element specifies by the user.
#include <windows.h>
#include <stdio.h>
#include <UIAutomation.h>

class EventHandler:
    public IUIAutomationStructureChangedEventHandler
{
private:
    LONG _refCount;

public:
    int _eventCount;

    // Constructor.
    EventHandler(): _refCount(1), _eventCount(0) 
    {
    }

    // IUnknown methods.
    ULONG STDMETHODCALLTYPE AddRef() 
    {
        ULONG ret = InterlockedIncrement(&_refCount);
        return ret;
    }

    ULONG STDMETHODCALLTYPE Release() 
    {
        ULONG ret = InterlockedDecrement(&_refCount);
        if (ret == 0) 
        {
            delete this;
            return 0;
        }
        return ret;
    }

    HRESULT STDMETHODCALLTYPE QueryInterface(REFIID riid, void** ppInterface) 
    {
        if (riid == __uuidof(IUnknown))
            *ppInterface=static_cast<IUIAutomationStructureChangedEventHandler*>(this);
        else if (riid == __uuidof(IUIAutomationStructureChangedEventHandler)) 
            *ppInterface=static_cast<IUIAutomationStructureChangedEventHandler*>(this);
        else 
        {
            *ppInterface = NULL;
            return E_NOINTERFACE;
        }
        this->AddRef();
        return S_OK;
    }

    // IUIAutomationStructureChangedEventHandler methods
    HRESULT STDMETHODCALLTYPE HandleStructureChangedEvent(IUIAutomationElement* pSender, StructureChangeType changeType, SAFEARRAY* pRuntimeID) {
        _eventCount++;
        switch (changeType) 
        {
            case StructureChangeType_ChildAdded:
                wprintf(L">> Structure Changed: ChildAdded! (count: %d)\n", _eventCount);
                break;
            case StructureChangeType_ChildRemoved:
                wprintf(L">> Structure Changed: ChildRemoved! (count: %d)\n", _eventCount);
                break;
            case StructureChangeType_ChildrenInvalidated:
                wprintf(L">> Structure Changed: ChildrenInvalidated! (count: %d)\n", _eventCount);
                break;
            case StructureChangeType_ChildrenBulkAdded:
                wprintf(L">> Structure Changed: ChildrenBulkAdded! (count: %d)\n", _eventCount);
                break;
            case StructureChangeType_ChildrenBulkRemoved:
                wprintf(L">> Structure Changed: ChildrenBulkRemoved! (count: %d)\n", _eventCount);
                break;
            case StructureChangeType_ChildrenReordered:
                wprintf(L">> Structure Changed: ChildrenReordered! (count: %d)\n", _eventCount);
                break;
        }
        return S_OK;
    }
};

int main(int argc, char* argv[]) 
{
    HRESULT hr;
    int ret = 0;
    IUIAutomationElement* pTargetElement = NULL;
    EventHandler* pEHTemp = NULL;

    CoInitializeEx(NULL,COINIT_MULTITHREADED);

    IUIAutomation* pAutomation=NULL;
    hr = CoCreateInstance(__uuidof(CUIAutomation), NULL, CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation), (void**)&pAutomation);
    if (FAILED(hr) || pAutomation == NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Use the mouse to point to the element you want to listen from.\n");
    Sleep(3000);

    // Make this application dots-per-inch (DPI) aware.
    SetProcessDPIAware();

    // Get mouse cursor position and get element from point.
    POINT pt;
    GetPhysicalCursorPos(&pt);
    hr = pAutomation->ElementFromPoint(pt, &pTargetElement);
    if (FAILED(hr) || pTargetElement == NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    pEHTemp = new EventHandler();
    if (pEHTemp == NULL) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Adding Event Handler.\n");
    hr = pAutomation->AddStructureChangedEventHandler(pTargetElement, TreeScope_Subtree, NULL, (IUIAutomationStructureChangedEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    wprintf(L"-Press any key to remove event handler and exit\n");
    getchar();

    wprintf(L"-Removing Event Handler.\n");
    hr = pAutomation->RemoveStructureChangedEventHandler(pTargetElement, (IUIAutomationStructureChangedEventHandler*) pEHTemp);
    if (FAILED(hr)) 
    {
        ret = 1;
        goto cleanup;
    }

    // Release resources and terminate.
cleanup:
    if (pEHTemp != NULL) 
        pEHTemp->Release();

    if (pTargetElement != NULL) 
        pTargetElement->Release();

    if (pAutomation != NULL) 
        pAutomation->Release();

    CoUninitialize();
    return ret;
}

Conceptual

Suscribirse a eventos de Automatización de la interfaz de usuario

Temas de procedimientos para clientes de Automatización de la interfaz de usuario