如何實作事件處理常式

發行項
06/13/2023

本主題包含範例程式碼，示範如何實作介面，讓用戶端接收及處理 Microsoft 消費者介面自動化事件。它會討論下列主題：

處理一般消費者介面自動化事件
處理Focus-Changed事件
處理Property-Changed事件
處理Structure-Changed事件
相關主題

處理一般消費者介面自動化事件

下列程式碼範例是 Microsoft Windows 主控台應用程式，可實作一般消費者介面自動化事件的消費者介面自動化事件處理常式。此範例會處理工具提示和其他視窗的建立和解構事件。

// 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;
}

處理Focus-Changed事件

下列程式碼範例是 Windows 主控台應用程式，可實作焦點變更事件的處理常式。

// 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;
}

處理Property-Changed事件

下列程式碼範例是 Windows 主控台應用程式，可實作屬性變更事件的處理常式。

// 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;
}

處理Structure-Changed事件

下列程式碼範例是 Windows 主控台應用程式，可實作結構變更事件的處理常式。

// 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;
}

概念
訂閱消費者介面自動化事件
消費者介面自動化用戶端的作法主題

共用方式為

如何實作事件處理常式

處理一般消費者介面自動化事件

處理Focus-Changed事件

處理Property-Changed事件

處理Structure-Changed事件

意見反應

其他資源

共用方式為

如何實作事件處理常式

處理一般消費者介面自動化事件

處理Focus-Changed事件

處理Property-Changed事件

處理Structure-Changed事件

相關主題

意見反應

其他資源