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How to Find UI Elements

  • Článek

This topic contains example code that shows how to find a UI elements in the UI Automation tree.

Finding an Element by Name

The following example finds the Microsoft UI Automation element that has the specified name and is a child of the desktop window.

IUIAutomationElement* GetTopLevelWindowByName(LPWSTR windowName)
{
    if (windowName == NULL)
    {
        return NULL;
    }

    VARIANT varProp;
    varProp.vt = VT_BSTR;
    varProp.bstrVal = SysAllocString(windowName);
    if (varProp.bstrVal == NULL)
    {
        return NULL;
    }

    IUIAutomationElement* pRoot = NULL;
    IUIAutomationElement* pFound = NULL;

    // Get the desktop element. 
    HRESULT hr = g_pAutomation->GetRootElement(&pRoot);
    if (FAILED(hr) || pRoot == NULL)
        goto cleanup;

    // Get a top-level element by name, such as "Program Manager"
    IUIAutomationCondition* pCondition;
    hr = g_pAutomation->CreatePropertyCondition(UIA_NamePropertyId, varProp, &pCondition);
    if (FAILED(hr))
        goto cleanup;

    pRoot->FindFirst(TreeScope_Children, pCondition, &pFound);

cleanup:
    if (pRoot != NULL)
        pRoot->Release();

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

    VariantClear(&varProp);
    return pFound;
}

The following example function returns a collection of all enabled buttons that are children of the specified element.

IUIAutomationElementArray* GetEnabledButtons(IUIAutomationElement* pParent)
{
    if (pParent == NULL)
    {
        return NULL;
    }
    IUIAutomationCondition* pButtonCondition = NULL;
    IUIAutomationCondition* pEnabledCondition = NULL;
    IUIAutomationCondition* pCombinedCondition = NULL;
    IUIAutomationElementArray* pFound = NULL;

    // Create a property condition for the button control type.
    VARIANT varProp;
    varProp.vt = VT_I4;
    varProp.lVal = UIA_ButtonControlTypeId;
    g_pAutomation->CreatePropertyCondition(UIA_ControlTypePropertyId, varProp, &pButtonCondition);
    if (pButtonCondition == NULL)
        goto cleanup;

    // Create a property condition for the enabled property.
    varProp.vt = VT_BOOL;
    varProp.boolVal = VARIANT_TRUE;
    g_pAutomation->CreatePropertyCondition(UIA_IsEnabledPropertyId, varProp, &pEnabledCondition);
    if (pEnabledCondition == NULL)
        goto cleanup;

    // Combine the conditions.
    g_pAutomation->CreateAndCondition(pButtonCondition, pEnabledCondition, &pCombinedCondition);
    if (pCombinedCondition == NULL)
        goto cleanup;

    // Find the matching elements. Note that if the scope is changed to TreeScope_Descendants, 
    // system buttons on the caption bar will be found as well.
    pParent->FindAll(TreeScope_Children, pCombinedCondition, &pFound);

cleanup:
    if (pButtonCondition != NULL)
        pButtonCondition->Release();

    if (pEnabledCondition != NULL) 
        pEnabledCondition->Release();
    
    if (pCombinedCondition != NULL)
        pCombinedCondition->Release();

    return pFound;
}

Conceptual

Obtaining UI Automation Elements

How-To Topics for UI Automation Clients