C# Scroll window(Chomre, FireFox) perticular pixel using Window handle

Question

Like previously I tried to get ScrollInfo of the window but it's not working on Chrome or other windows where they are using a custom scroll bar....

So it's possible to scroll windows by code particular height like I want to scroll Chomre window 100 Pixel?

i tried to scroll windows by mouse delta also but it's different for each window.. so looking for a fixed like want to scroll 100 pixels for any type of window(Chrome, Visual Studio etc)

Code I tried

InputHelpers.SendVerticalMouseWheel(-100);

internal class InputHelpers
    {
        internal static bool SendKeyPress(VirtualKeyCode keyCode)
        {
            var manager = new InputManager();
            manager.SendKeyPress(keyCode);
            return manager.SendInputs();
        }

        internal static bool SendVerticalMouseWheel(int delta)
        {
            InputManager inputManager = new InputManager();
            inputManager.AddVerticalMouseWheel(delta);
            return inputManager.SendInputs();
        }

        internal static bool SendHorizontalMouseWheel(int delta)
        {
            InputManager inputManager = new InputManager();
            inputManager.AddHorizontalMouseWheel(delta);
            return inputManager.SendInputs();
        }
    }

public class InputManager
    {
        public List<INPUT> InputList { get; private set; }

        public InputManager()
        {
            InputList = new List<INPUT>();
        }

        internal void SendKeyPress(VirtualKeyCode key)
        {
            INPUT input = new INPUT();
            input.Type = InputType.InputKeyboard;
            input.Data.Keyboard = new KEYBDINPUT();
            input.Data.Keyboard.wVk = key;
            input.Data.Keyboard.dwFlags = KeyboardEventFlags.KEYEVENTF_KEYUP;
            InputList.Add(input);

            input = new INPUT();
            input.Type = InputType.InputKeyboard;
            input.Data.Keyboard = new KEYBDINPUT();
            input.Data.Keyboard.wVk = key;
            InputList.Add(input);
        }

        internal void AddVerticalMouseWheel(int delta)
        {
            INPUT input = new INPUT();
            input.Type = InputType.InputMouse;
            input.Data.Mouse = new MOUSEINPUT();
            input.Data.Mouse.dwFlags = MouseEventFlags.MOUSEEVENTF_WHEEL;
            input.Data.Mouse.mouseData = (uint)delta;
            InputList.Add(input);
        }

        internal void AddHorizontalMouseWheel(int delta)
        {
            INPUT input = new INPUT();
            input.Type = InputType.InputMouse;
            input.Data.Mouse = new MOUSEINPUT();
            input.Data.Mouse.dwFlags = MouseEventFlags.MOUSEEVENTF_HWHEEL;
            input.Data.Mouse.mouseData = (uint)delta;
            InputList.Add(input);
        }

        public bool SendInputs()
        {
            INPUT[] inputList = InputList.ToArray();
            uint len = (uint)inputList.Length;
            uint successfulInputs = NativeMethods.SendInput(len, inputList, Marshal.SizeOf(typeof(INPUT)));
            return successfulInputs == len;
        }
    }

[DllImport("user32.dll")]         public static extern uint SendInput(uint nInputs, [MarshalAs(UnmanagedType.LPArray), In] INPUT[] pInputs, int cbSize);

Answer 1

The code uses IUIAutomation::ElementFromPoint for quick test. Let the mouse hover over the scroll bar to retrieve the UI Automation element.

#include <Windows.h>
#include <UIAutomation.h>
#include <wchar.h>

int Element(IUIAutomation* automation)
{
    // Get the element under the cursor
// Use GetPhysicalCursorPos to interact properly with
// High DPI
    POINT pt;
    GetPhysicalCursorPos(&pt);

    IUIAutomationElement* pAtMouse;
    HRESULT hr = automation->ElementFromPoint(pt, &pAtMouse);
    if (FAILED(hr))
        return hr;

    // Get the element's name and print it
    BSTR name;
    hr = pAtMouse->get_CurrentName(&name);
    if (SUCCEEDED(hr))
    {
        wprintf(L"Element's Name: %s \n", name);
        SysFreeString(name);

        //IUIAutomationValuePattern* pattern;
        //pAtMouse->GetCurrentPatternAs(UIA_ValuePatternId, IID_IUIAutomationValuePattern,(void**)&pattern);
        IUIAutomationLegacyIAccessiblePattern* pattern;

        //pAtMouse->GetCurrentPatternAs(UIA_LegacyIAccessiblePatternId, IID_IUIAutomationLegacyIAccessiblePattern,(void**)&pattern);
        pAtMouse->GetCurrentPatternAs(UIA_LegacyIAccessiblePatternId, IID_PPV_ARGS(&pattern));
        //TODO
        BSTR url = nullptr;
        pattern->get_CurrentValue(&url);
        DWORD state = 0;
        pattern->get_CurrentState(&state);
        BSTR elename = nullptr;
        pattern->get_CurrentName(&elename);
        DWORD role = 0;
        pattern->get_CurrentRole(&role);
        //wprintf(L"Element's ValuePattern: %s \n", url);
        SysFreeString(url);
        SysFreeString(elename);
    }
    IUIAutomationScrollPattern* pattern1;
    if (pAtMouse->GetCurrentPatternAs(UIA_ScrollPatternId, IID_PPV_ARGS(&pattern1)) == S_OK)
    {
        wprintf(L"Success! \n");
        if (pattern1)
        {
            BOOL b{};
            pattern1->get_CurrentVerticallyScrollable(&b);
            double size;
            pattern1->get_CurrentVerticalViewSize(&size);
            double p;
            pattern1->get_CurrentVerticalScrollPercent(&p);
            pattern1->SetScrollPercent(0,p+1.0);

            wprintf(L"get_CurrentVerticalViewSize:%f get_CurrentVerticalScrollPercent:%f\n", size, p);
        }
    }

    // Get the element's Control Type (in the current languange)
    // and print it
    BSTR controlType;
    hr = pAtMouse->get_CurrentLocalizedControlType(&controlType);
    if (SUCCEEDED(hr))
    {
        wprintf(L"Element's Control Type: %s \n", controlType);
        SysFreeString(controlType);
    }

    // Clean up our COM pointers
    pAtMouse->Release();
    return hr;
}

int main(int argc, TCHAR* argv[])
{
    // Initialize COM and create the main Automation object
    IUIAutomation* g_pAutomation;
    CoInitialize(NULL);
    HRESULT hr = CoCreateInstance(__uuidof(CUIAutomation), NULL,
        CLSCTX_INPROC_SERVER, __uuidof(IUIAutomation),
        (void**)&g_pAutomation);
    if (FAILED(hr))
        return (hr);

    bool quit = false;
    while (!quit)
    {
        SHORT leftControlMod = GetAsyncKeyState(VK_LCONTROL);
        if (leftControlMod != 0)
        {
            Element(g_pAutomation);
            Sleep(100);
        }
        quit = GetAsyncKeyState(VK_ESCAPE);
    }

    g_pAutomation->Release();
    CoUninitialize();
    return 0;
}