当应用程序不在焦点时，WPF Listview 不滚动（使用鼠标滚轮）

Question

我有一个 WPF 应用程序（用 C# 编写），它有一个 Listview 控件，当应用程序处于焦点时，该控件可以用鼠标滚轮完美滚动。 但是，当应用程序不在焦点上时，即使鼠标指针位于应用程序和列表视图区域上，Listview 也不会滚动。我继续在应用程序上看到与鼠标悬停相关的效果，但没有收到鼠标滚轮事件。这与大多数其他应用程序在我的桌面上的工作方式是一致的，但是其中一些（如 Facebook Messenger）支持无焦点滚动，我想在我的 WPF 应用程序中模仿。

我搜索了 MSDN 论坛和 Stackoverflow，并看到了 Windows 窗体的多种解决方案，但它们是 5 年前提出的问题，我想知道是否有人在 .net 4.5 上相对轻松地做到了，并且可以指出可能的解决方案.

---编辑---

感谢这个帖子C# ListView mouse wheel scroll without focus，我能够在这方面取得一定程度的进步

这是接收鼠标滚轮的函数的外观

private static IntPtr HookCallback(
int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0 &&
MouseMessages.WM_MOUSEWHEEL == (MouseMessages)wParam)
        {
            MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
            Console.WriteLine(hookStruct.pt.x + ", " + hookStruct.pt.y);
            Console.WriteLine((short)((hookStruct.mouseData)>>16));                
            MouseWheelEventArgs myArgs = new MouseWheelEventArgs(System.Windows.Input.Mouse.PrimaryDevice, (int)hookStruct.time, (short)((hookStruct.mouseData)>>16));
            myMainFrame.SidePanelControl.ScrollTheListView(myArgs);
            }
        return CallNextHookEx(_hookID, nCode, wParam, lParam);
    }

如您所见，我正在初始化一个 MouseWheelEventArgs 实例并具有时间、增量和鼠标设备属性。

如何将此鼠标滚轮事件传递给我的列表视图滚动查看器？

Answer 1

设法让这个工作。这是我的课。 使用该类所需要做的就是

1. 初始化 InterceptMouse，将 app/listview/etc 指针传递给它
2. 当应用不在焦点但发生了相应的 mouseenter 事件时开始拦截鼠标。
3. 只要事件是 mousewheel，listview 的 scrollviewer 就会收到 mouseWheel 事件。
4. 当应用程序被激活或 mouseleave 被调用时停止拦截鼠标。

---

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.InteropServices;
using System.Windows.Interop;
using System.Windows.Forms;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Input;
using System.Diagnostics;
using System.Windows.Forms.Integration;
namespace myApp.HelperClasses
{
    public class InterceptMouse
    {
        public static System.Windows.Controls.ListView myListview;
        private static LowLevelMouseProc _proc = HookCallback;
        private static IntPtr _hookID = IntPtr.Zero;


        public InterceptMouse(System.Windows.Controls.ListView myListviewParam)
        {
            myListview = myListviewParam;
        }

        public static void StartIntercepting()
        {
            _hookID = SetHook(_proc);
        }
        public static void StopIntercepting()
        {
            UnhookWindowsHookEx(_hookID);
        }

        private static IntPtr SetHook(LowLevelMouseProc proc)
        {
            using (Process curProcess = Process.GetCurrentProcess())
            using (ProcessModule curModule = curProcess.MainModule)
            {
                return SetWindowsHookEx(WH_MOUSE_LL, proc,
                    GetModuleHandle(curModule.ModuleName), 0);
            }
        }

        private delegate IntPtr LowLevelMouseProc(int nCode, IntPtr wParam, IntPtr lParam);


        private static IntPtr HookCallback(
            int nCode, IntPtr wParam, IntPtr lParam)
        {
            if (nCode >= 0 &&
                MouseMessages.WM_MOUSEWHEEL == (MouseMessages)wParam)
            {
                MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
                //Console.WriteLine(hookStruct.pt.x + ", " + hookStruct.pt.y + "," + hookStruct.mouseData);

                var delta = (short)((hookStruct.mouseData) >> 16);
                var mouse = InputManager.Current.PrimaryMouseDevice;
                var args = new MouseWheelEventArgs(mouse, Environment.TickCount, delta);
                args.RoutedEvent = WindowsFormsHost.MouseWheelEvent;

                Decorator border = VisualTreeHelper.GetChild(myListview, 0) as Decorator;
                // Get scrollviewer
                ScrollViewer scrollViewer = border.Child as ScrollViewer;
                scrollViewer.RaiseEvent(args);
            }
            return CallNextHookEx(_hookID, nCode, wParam, lParam);
        }



        private const int WH_MOUSE_LL = 14;

        private enum MouseMessages
        {
            WM_LBUTTONDOWN = 0x0201,
            WM_LBUTTONUP = 0x0202,
            WM_MOUSEMOVE = 0x0200,
            WM_MOUSEWHEEL = 0x020A,
            WM_RBUTTONDOWN = 0x0204,
            WM_RBUTTONUP = 0x0205
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct POINT
        {
            public int x;
            public int y;
        }

        [StructLayout(LayoutKind.Sequential)]
        private struct MSLLHOOKSTRUCT
        {
            public POINT pt;
            public uint mouseData;
            public uint flags;
            public uint time;
            public IntPtr dwExtraInfo;
        }

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr SetWindowsHookEx(int idHook,
            LowLevelMouseProc lpfn, IntPtr hMod, uint dwThreadId);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        [return: MarshalAs(UnmanagedType.Bool)]
        private static extern bool UnhookWindowsHookEx(IntPtr hhk);

        [DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr CallNextHookEx(IntPtr hhk, int nCode,
            IntPtr wParam, IntPtr lParam);

        [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
        private static extern IntPtr GetModuleHandle(string lpModuleName);
    }
}