How do you get the NamePropertyId of a UIAutomationElement by hovering the cursor?

Question

I am trying to build my own screen reader using UIAutomation. I want my program to return the NameProperty of the element that is pointed by my cursor

This is what I have done so far; this is just sample code anyway:

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

const int MAX_WND_TEXT = 60;

IUIAutomation *automation = NULL;

BOOL InitializeUIAutomation(IUIAutomation **pAutomation)
{
    CoInitialize(NULL);
    HRESULT hr = CoCreateInstance(__uuidof(CUIAutomation), NULL,
        CLSCTX_INPROC_SERVER,
        __uuidof(IUIAutomation), (void**)pAutomation);
    return (SUCCEEDED(hr));
}

int main()
{
    POINT p;

    IUIAutomationElement *elem;
    wchar_t wndName[MAX_WND_TEXT];
    BOOL stat = InitializeUIAutomation(&automation);
    while (true)
    {
        if (stat)
        {
            GetCursorPos(&p);
            HRESULT hr = automation->ElementFromPoint(p, &elem);
            if (SUCCEEDED(hr))
            {
                HRESULT hr = elem->GetCurrentPropertyValue(UIA_NamePropertyId,
                    (VARIANT*)wndName);
                if (SUCCEEDED(hr))
                    std::cout << wndName << std::endl;
                else
                    wndName[0] = '\0';
            }
            else
                std::cout << "No element selected." << std::endl;

            Sleep(100);
            elem->Release();
        }
    }
    automation->Release();
    CoUninitialize();
    return 0;
}

Now the problem is I can't make it to print the values I wanted. The program just output a specific hex number. And also I'm still a beginner in UIAutomation so I am still lost.

Can you help me or give me tips how to solve my problem?

score 1 · Accepted Answer · answered Jan 24 '19 at 05:01

Solved my problem using this code.

#include <iostream>
#include <string>
#include <Windows.h>
#include <UIAutomation.h>

BOOL InitializeUIAutomation(IUIAutomation **automation)
{
    CoInitialize(NULL);
    HRESULT hr = CoCreateInstance(__uuidof(CUIAutomation), NULL,
        CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation),
        (void**)automation);
    return (SUCCEEDED(hr));
}

int main()
{
    IUIAutomation *automation = NULL;
    IUIAutomationElement *elem = NULL;
    BOOL stat = InitializeUIAutomation(&automation);
    POINT mousePt;
    BSTR elemName = NULL;
    if (stat)
    {
        while(true)
        {
            GetCursorPos(&mousePt);
            HRESULT hr = automation->ElementFromPoint(mousePt, &elem);
            if (SUCCEEDED(hr) && elem != NULL)
            {
                elem->get_CurrentName(&elemName);
                std::wstring ws(elemName, SysStringLen(elemName));
                std::wcout << ws << std::endl;
            }
            SysFreeString(elemName);
            elem->Release();
            Sleep(200);
        }
    }
    automation->Release();
    CoUninitialize();

    return 0;
}

The hex numbers printed was the BSTR header after all. Solve my problem by converting BSTR to wstring.

Thanks, is there any way i can know that is that element is invokable(buttons are invokable) ,Expandable(Combo boxes are expandable) , or selectable (list items are selectable )?? — the_learnist, Sep 02 '20 at 16:33

How do you get the NamePropertyId of a UIAutomationElement by hovering the cursor?

1 Answers1