拖放时可以使用鼠标滚轮吗?

您应该查看 SetWindowsHookEx 和 CALLBACK LowLevelMouseProc 即可了解该技术在此背后.此事件不仅限于您的应用程序，还可以将鼠标捕获到窗体外部，因此它也可以在您无法使用本地事件的操作中使用.In WinForms, after calling a DoDragDrop to start dragging an item, controls no longer scroll with the mouse-wheel, and the control's MouseWheel event is no longer called, until the user drops whatever he is dragging.Is there a way to get the mouse wheel to work while dragging? 解决方案 You could get a global MouseWheel with a keyboard hook.using System;using System.ComponentModel;using System.Runtime.InteropServices;using System.Windows.Forms;using Microsoft.Win32.SafeHandles;using BOOL = System.Boolean;using DWORD = System.UInt32;using HHOOK = SafeHookHandle;using HINSTANCE = System.IntPtr;using HOOKPROC = HookProc;using LPARAM = System.IntPtr;using LRESULT = System.IntPtr;using POINT = System.Drawing.Point;using ULONG_PTR = System.IntPtr;using WPARAM = System.IntPtr;public delegate LRESULT HookProc(int nCode, WPARAM wParam, LPARAM lParam);internal static class NativeMethods{ [DllImport("User32.dll", SetLastError = true)] internal static extern HHOOK SetWindowsHookEx( HookType idHook, HOOKPROC lpfn, HINSTANCE hMod, DWORD dwThreadId); [DllImport("User32.dll")] internal static extern LRESULT CallNextHookEx( HHOOK hhk, int nCode, WPARAM wParam, LPARAM lParam); [DllImport("User32.dll", SetLastError = true)] [return: MarshalAs(UnmanagedType.Bool)] internal static extern BOOL UnhookWindowsHookEx( IntPtr hhk); [DllImport("kernel32.dll", CharSet = CharSet.Auto)] public static extern IntPtr GetModuleHandle(string lpModuleName);}internal static class NativeTypes{ internal enum MSLLHOOKSTRUCTFlags : uint { LLMHF_INJECTED = 0x00000001U, } [StructLayout(LayoutKind.Sequential)] internal struct MSLLHOOKSTRUCT { internal POINT pt; internal DWORD mouseData; internal MSLLHOOKSTRUCTFlags flags; internal DWORD time; internal ULONG_PTR dwExtraInfo; }}internal static class NativeConstants{ internal const int WH_MOUSE_LL = 14; internal const int HC_ACTION = 0; internal const int WM_MOUSEWHEEL = 0x020A; internal const int WM_MOUSEHWHEEL = 0x020E; internal const int WHEEL_DELTA = 120;}public enum HookType{ LowLevelMouseHook = NativeConstants.WH_MOUSE_LL}public enum HookScope{ LowLevelGlobal,}public class SafeHookHandle : SafeHandleZeroOrMinusOneIsInvalid{ private SafeHookHandle() : base(true) { } public static SafeHookHandle SetWindowsHook(HookType idHook, HookProc lpfn, IntPtr hMod, uint dwThreadId) { var hhk = NativeMethods.SetWindowsHookEx(idHook, lpfn, hMod, dwThreadId); if(hhk.IsInvalid) { throw new Win32Exception(); } else { return hhk; } } public IntPtr CallNextHook(int nCode, IntPtr wParam, IntPtr lParam) { return NativeMethods.CallNextHookEx(this, nCode, wParam, lParam); } protected override bool ReleaseHandle() { return NativeMethods.UnhookWindowsHookEx(this.handle); }}public abstract class WindowsHook : IDisposable{ private SafeHookHandle hhk; private HookProc lpfn; protected WindowsHook(HookType idHook, HookScope scope) { this.lpfn = this.OnWindowsHook; switch(scope) { case HookScope.LowLevelGlobal: IntPtr moduleHandle = NativeMethods.GetModuleHandle(null); this.hhk = SafeHookHandle.SetWindowsHook(idHook, this.lpfn, moduleHandle, 0U); return; default: throw new InvalidEnumArgumentException("scope", (int)scope, typeof(HookScope)); } } protected virtual IntPtr OnWindowsHook(int nCode, IntPtr wParam, IntPtr lParam) { return this.hhk.CallNextHook(nCode, wParam, lParam); } public void Dispose() { this.Dispose(true); GC.SuppressFinalize(this); } protected virtual void Dispose(bool disposing) { if(disposing) { if(this.hhk != null) { this.hhk.Dispose(); } } }}public class LowLevelMouseHook : WindowsHook{ public event MouseEventHandler MouseWheel; public LowLevelMouseHook() : base(HookType.LowLevelMouseHook, HookScope.LowLevelGlobal) { } protected sealed override IntPtr OnWindowsHook(int nCode, IntPtr wParam, IntPtr lParam) { if(nCode == NativeConstants.HC_ACTION) { var msLLHookStruct = (NativeTypes.MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(NativeTypes.MSLLHOOKSTRUCT)); switch(wParam.ToInt32()) { case NativeConstants.WM_MOUSEWHEEL: case NativeConstants.WM_MOUSEHWHEEL: this.OnMouseWheel(new MouseEventArgs(Control.MouseButtons, 0, msLLHookStruct.pt.X, msLLHookStruct.pt.Y, (int)msLLHookStruct.mouseData >> 16)); break; } } return base.OnWindowsHook(nCode, wParam, lParam); } protected virtual void OnMouseWheel(MouseEventArgs e) { if(this.MouseWheel != null) { this.MouseWheel(this, e); } }}Sample Usage:using (LowLevelMouseHook hook = new LowLevelMouseHook()){ hook.MouseWheel += (sender, e) => { Console.WriteLine(e.Delta); }; Application.Run();}The code provides a class LowLevelMouseHook with an event MouseWheel that behaves like the event from the builtin windows forms control classes.(Moreover the code is split into an abstract class WindowsHooks for use with other hooks, a SafeHookHandle class to ensure the handle is released and the helper classes for native methods)You should look at SetWindowsHookEx and CALLBACK LowLevelMouseProc to understand the technique behind this.This event is not limited to your application but will also capture the mouse outside your form, so it should also work for your operations where you can not use the local events. 这篇关于拖放时可以使用鼠标滚轮吗?的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！ 上岸，阿里云！