今天在处理客户问题时，发现了个有趣的问题，客户电脑的任务栏设置在左侧，然后打开公司软件最大化后，软件左侧就会被任务栏挡住，右侧又会出现空白没有铺满，看这情况明显是因为任务栏的位置导致的。
当时打开了其他如谷歌浏览器、钉钉等最大化都没问题，看来不是需要系统设置的问题。测试发现winform原生的窗体带边框的话最大化是没问题的，只有当边框为null的时候，才会出现现在的问题。
遇到问题了首先百度下，找找思路，查询下找到了个仁兄写的：思路大概就是重写windows消息处理事件，在事件里当遇到最大化事件类型时，重新计划下窗体的位置再显示。代码如下：
(只需将此类复制到您的项目中)
using System; using System.Collections.Generic; using System.Linq; using System.Runtime.InteropServices; using System.Text; using System.Threading.Tasks; namespace WindowsFormsApp1 { public static class Native { [DllImport("user32")] internal static extern bool GetMonitorInfo(IntPtr hMonitor, MONITORINFO lpmi); [DllImport("user32")] internal static extern IntPtr MonitorFromWindow(IntPtr handle, int flags); public static void WmGetMinMaxInfo(IntPtr hwnd, IntPtr lParam, int minWidth, int minHeight) { MINMAXINFO mmi = (MINMAXINFO)Marshal.PtrToStructure(lParam, typeof(MINMAXINFO)); // Adjust the maximized size and position to fit the work area of the correct monitor int MONITOR_DEFAULTTONEAREST = 0x00000002; IntPtr monitor = Native.MonitorFromWindow(hwnd, MONITOR_DEFAULTTONEAREST); if (monitor != IntPtr.Zero) { Native.MONITORINFO monitorInfo = new Native.MONITORINFO(); Native.GetMonitorInfo(monitor, monitorInfo); Native.RECT rcWorkArea = monitorInfo.rcWork; Native.RECT rcMonitorArea = monitorInfo.rcMonitor; mmi.ptMaxPosition.x = Math.Abs(rcWorkArea.left - rcMonitorArea.left); mmi.ptMaxPosition.y = Math.Abs(rcWorkArea.top - rcMonitorArea.top); mmi.ptMaxSize.x = Math.Abs(rcWorkArea.right - rcWorkArea.left); mmi.ptMaxSize.y = Math.Abs(rcWorkArea.bottom - rcWorkArea.top); mmi.ptMinTrackSize.x = minWidth; mmi.ptMinTrackSize.y = minHeight; } Marshal.StructureToPtr(mmi, lParam, true); } /// <summary> /// POINT aka POINTAPI /// </summary> [StructLayout(LayoutKind.Sequential)] public struct POINT { /// <summary> /// x coordinate of point. /// </summary> public int x; /// <summary> /// y coordinate of point. /// </summary> public int y; /// <summary> /// Construct a point of coordinates (x,y). /// </summary> public POINT(int x, int y) { this.x = x; this.y = y; } } [StructLayout(LayoutKind.Sequential)] public struct MINMAXINFO { public POINT ptReserved; public POINT ptMaxSize; public POINT ptMaxPosition; public POINT ptMinTrackSize; public POINT ptMaxTrackSize; }; /// <summary> /// </summary> [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)] public class MONITORINFO { /// <summary> /// </summary> public int cbSize = Marshal.SizeOf(typeof(MONITORINFO)); /// <summary> /// </summary> public RECT rcMonitor = new RECT(); /// <summary> /// </summary> public RECT rcWork = new RECT(); /// <summary> /// </summary> public int dwFlags = 0; } /// <summary> Win32 </summary> [StructLayout(LayoutKind.Sequential, Pack = 0)] public struct RECT { /// <summary> Win32 </summary> public int left; /// <summary> Win32 </summary> public int top; /// <summary> Win32 </summary> public int right; /// <summary> Win32 </summary> public int bottom; /// <summary> Win32 </summary> public static readonly RECT Empty = new RECT(); /// <summary> Win32 </summary> public int Width { get { return Math.Abs(right - left); } // Abs needed for BIDI OS } /// <summary> Win32 </summary> public int Height { get { return bottom - top; } } /// <summary> Win32 </summary> public RECT(int left, int top, int right, int bottom) { this.left = left; this.top = top; this.right = right; this.bottom = bottom; } /// <summary> Win32 </summary> public RECT(RECT rcSrc) { this.left = rcSrc.left; this.top = rcSrc.top; this.right = rcSrc.right; this.bottom = rcSrc.bottom; } /// <summary> Win32 </summary> public bool IsEmpty { get { // BUGBUG : On Bidi OS (hebrew arabic) left > right return left >= right || top >= bottom; } } /// <summary> Return a user friendly representation of this struct </summary> public override string ToString() { if (this == RECT.Empty) { return "RECT {Empty}"; } return "RECT { left :" + left + " / top :" + top + " / right :" + right + " / bottom :" + bottom + " }"; } /// <summary> Determine if 2 RECT are equal (deep compare) </summary> public override bool Equals(object obj) { if (!(obj is RECT)) { return false; } return (this == (RECT)obj); } /// <summary>Return the HashCode for this struct (not garanteed to be unique)</summary> public override int GetHashCode() { return left.GetHashCode() + top.GetHashCode() + right.GetHashCode() + bottom.GetHashCode(); } /// <summary> Determine if 2 RECT are equal (deep compare)</summary> public static bool operator ==(RECT rect1, RECT rect2) { return (rect1.left == rect2.left && rect1.top == rect2.top && rect1.right == rect2.right && rect1.bottom == rect2.bottom); } /// <summary> Determine if 2 RECT are different(deep compare)</summary> public static bool operator !=(RECT rect1, RECT rect2) { return !(rect1 == rect2); } } } }
窗口上的调用：
winform的：
protected override void WndProc(ref Message m) { switch (m.Msg) { case 0x0024: Native.WmGetMinMaxInfo(m.HWnd, m.LParam, (int)this.Width, (int)Height); break; } base.WndProc(ref m); }
WPF的：
public partial class MainWindow : Window { public MainWindow() { SourceInitialized += Window_SourceInitialized; InitializeComponent(); } void Window_SourceInitialized(object sender, EventArgs e) { IntPtr handle = new WindowInteropHelper(this).Handle; HwndSource.FromHwnd(handle)?.AddHook(WindowProc); } private IntPtr WindowProc(IntPtr hwnd, int msg, IntPtr wParam, IntPtr lParam, ref bool handled) { switch (msg) { case 0x0024: Native.WmGetMinMaxInfo(hwnd, lParam, (int)MinWidth, (int)MinHeight); handled = true; break; } return (IntPtr)0; } }