WPF 触摸屏显示器检测问题

Question

我正在努力使我的 wpf 应用程序触摸启用。我已连接到触摸屏辅助显示器。

我面临一个问题。所有触摸事件都被解释为鼠标（单击）事件。使用下面的代码（通过 GPT-4）我尝试获取所有输入设备。

现在奇怪的是，当我逐行调试下面的代码时，触摸事件按预期工作，但是当我正常运行此代码（即没有断点和调试）时，触摸事件不起作用。

可能是什么原因？

[System.Runtime.InteropServices.DllImport("user32.dll")]
static extern uint GetRawInputDeviceList(IntPtr pRawInputDeviceList, ref uint puiNumDevices, uint cbSize);


uint deviceCount = 0;
uint size = (uint)System.Runtime.InteropServices.Marshal.SizeOf(typeof(RAWINPUTDEVICELIST));
                 
if (GetRawInputDeviceList(IntPtr.Zero, ref deviceCount, size) == 0)
{
    
    // Allocate the array for the devices
    IntPtr pRawInputDeviceList = System.Runtime.InteropServices.Marshal.AllocHGlobal((int)(size * deviceCount));

    // Get the list
    GetRawInputDeviceList(pRawInputDeviceList, ref deviceCount, size);

    // Iterate through the list, processing or displaying device info as needed
    

    for (int i = 0; i < deviceCount; i++)
    {
        
        // Marshal the list of RAWINPUTDEVICELIST structs
        RAWINPUTDEVICELIST rid = Marshal.PtrToStructure<RAWINPUTDEVICELIST>(
            new IntPtr((long)pRawInputDeviceList + (size * i)));

        // Process the rid as needed
        Debug.WriteLine($"Device Handle: {rid.hDevice}, Type: {rid.dwType}");
    }
   // Marshal.FreeHGlobal(pRawInputDeviceList);
}

Answer 1

P/Invoke 可以简单得多。

using System.Diagnostics;
using System.Runtime.InteropServices;

internal static class DeviceHelper
{
    [DllImport("User32", SetLastError = true)]
    private static extern uint GetRawInputDeviceList(
        [Out] RAWINPUTDEVICELIST[] pRawInputDeviceList,
        ref uint puiNumDevices,
        uint cbSize);

    [StructLayout(LayoutKind.Sequential)]
    private struct RAWINPUTDEVICELIST
    {
        public IntPtr hDevice;
        public uint dwType;
    }

    public static void FindInputDevices()
    {
        uint deviceListCount = 0;
        uint rawInputDeviceListSize = (uint)Marshal.SizeOf<RAWINPUTDEVICELIST>();

        if (GetRawInputDeviceList(
            null,
            ref deviceListCount,
            rawInputDeviceListSize) == 0)
        {
            var devices = new RAWINPUTDEVICELIST[deviceListCount];

            if (GetRawInputDeviceList(
                devices,
                ref deviceListCount,
                rawInputDeviceListSize) == deviceListCount)
            {
                foreach (var device in devices)
                {
                    Trace.WriteLine($"Handle: {device.hDevice} Type: {device.dwType}");
                }
            }
        }
    }
}