c# - 在无边界 WinForm 上投影

Question

我试图像第一张图片一样在整个表单周围投下阴影，除了那是 WPF，而不是 WinForm。现在我想在winform上投下同样的阴影。

这就是我想要的..¬

不是这个..¬

Answer 1

In WinForms, you can just override the form's protected CreateParams property and add the CS_DROPSHADOW flag to the class styles. For example:

public class ShadowedForm : Form {
    protected override CreateParams CreateParams {
        get {
            const int CS_DROPSHADOW = 0x20000;
            CreateParams cp = base.CreateParams;
            cp.ClassStyle |= CS_DROPSHADOW;
            return cp;
        }
    }

    // ... other code ...
}

But, a couple of caveats…

1. This flag works only on top-level windows. In Win32-speak, that means overlapped and popup windows. It has no effect on child windows (e.g. controls). I thought I remembered hearing somewhere that this limitation had been removed from Windows 8, but I can't find a link confirming this and I don't have Windows 8 installed for testing purposes.

2. It is possible that the user has disabled this feature altogether. If so, you won't get drop shadows, no matter how you ask for them. That's by design. Your application should not try and override this request. You can determine whether drop shadows are enabled or disabled by P/Invoking the SystemParametersInfo function and passing the SPI_GETDROPSHADOW flag.

3. The Aero theme also adds shadows to top-level windows. This effect is separate and distinct from CS_DROPSHADOW, and works only when Aero is enabled. There's no way to turn it off and on for individual windows. Moreover, since the Aero theme has been removed from Windows 8, it won't ever have these shadows.

Answer 2

这是我的 C# 实现。这与阿尔类似。Petro 的，但是您会注意到，当您失去焦点并重新获得焦点时，阴影会重新绘制自己。

我还添加了允许鼠标拖动的代码。

public partial class Form1: Form
{
    [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
    private static extern IntPtr CreateRoundRectRgn
    (
        int nLeftRect, // x-coordinate of upper-left corner
        int nTopRect, // y-coordinate of upper-left corner
        int nRightRect, // x-coordinate of lower-right corner
        int nBottomRect, // y-coordinate of lower-right corner
        int nWidthEllipse, // height of ellipse
        int nHeightEllipse // width of ellipse
     );        

    [DllImport("dwmapi.dll")]
    public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarInset);

    [DllImport("dwmapi.dll")]
    public static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);

    [DllImport("dwmapi.dll")]
    public static extern int DwmIsCompositionEnabled(ref int pfEnabled);

    private bool m_aeroEnabled;                     // variables for box shadow
    private const int CS_DROPSHADOW = 0x00020000;
    private const int WM_NCPAINT = 0x0085;
    private const int WM_ACTIVATEAPP = 0x001C;

    public struct MARGINS                           // struct for box shadow
    {
        public int leftWidth;
        public int rightWidth;
        public int topHeight;
        public int bottomHeight;
    }

    private const int WM_NCHITTEST = 0x84;          // variables for dragging the form
    private const int HTCLIENT = 0x1;
    private const int HTCAPTION = 0x2;

    protected override CreateParams CreateParams
    {
        get
        {
            m_aeroEnabled = CheckAeroEnabled();

            CreateParams cp = base.CreateParams;
            if (!m_aeroEnabled)
                cp.ClassStyle |= CS_DROPSHADOW;

            return cp;
        }
    }

    private bool CheckAeroEnabled()
    {
        if (Environment.OSVersion.Version.Major >= 6)
        {
            int enabled = 0;
            DwmIsCompositionEnabled(ref enabled);
            return (enabled == 1) ? true : false;
        }
        return false;
    }

    protected override void WndProc(ref Message m)
    {
        switch (m.Msg)
        {
            case WM_NCPAINT:                        // box shadow
                if (m_aeroEnabled)
                {
                    var v = 2;
                    DwmSetWindowAttribute(this.Handle, 2, ref v, 4);
                    MARGINS margins = new MARGINS()
                    {
                        bottomHeight = 1,
                        leftWidth = 1,
                        rightWidth = 1,
                        topHeight = 1
                    };
                    DwmExtendFrameIntoClientArea(this.Handle, ref margins);

                }
                break;
            default:
                break;
        }
        base.WndProc(ref m);

        if (m.Msg == WM_NCHITTEST && (int)m.Result == HTCLIENT)     // drag the form
            m.Result = (IntPtr)HTCAPTION;

    }

    public Form1()
    {
        m_aeroEnabled = false;

        this.FormBorderStyle = FormBorderStyle.None;

        InitializeComponent();
    }
}

Answer 3

嗯，，，刚刚过去的代码，你会得到像这样的 Windows 7 投影 >>> http://marcin.floryan.pl/wp-content/uploads/2010/08/WPF-Window-native-shadow。 PNG

Imports System.Runtime.InteropServices

Public Class IMSS_SplashScreen
    Private aeroEnabled As Boolean
    Protected Overrides ReadOnly Property CreateParams() As CreateParams
        Get
            CheckAeroEnabled()
            Dim cp As CreateParams = MyBase.CreateParams
            If Not aeroEnabled Then
                cp.ClassStyle = cp.ClassStyle Or NativeConstants.CS_DROPSHADOW
                Return cp
            Else
                Return cp
            End If
        End Get
    End Property
    Protected Overrides Sub WndProc(ByRef m As Message)
        Select Case m.Msg
            Case NativeConstants.WM_NCPAINT
                Dim val = 2
                If aeroEnabled Then
                    NativeMethods.DwmSetWindowAttribute(Handle, 2, val, 4)
                    Dim bla As New NativeStructs.MARGINS()
                    With bla
                        .bottomHeight = 1
                        .leftWidth = 1
                        .rightWidth = 1
                        .topHeight = 1
                    End With
                    NativeMethods.DwmExtendFrameIntoClientArea(Handle, bla)
                End If
                Exit Select
        End Select
        MyBase.WndProc(m)
    End Sub
    Private Sub CheckAeroEnabled()
        If Environment.OSVersion.Version.Major >= 6 Then
            Dim enabled As Integer = 0
            Dim response As Integer = NativeMethods.DwmIsCompositionEnabled(enabled)
            aeroEnabled = (enabled = 1)
        Else
            aeroEnabled = False
        End If
    End Sub
End Class
Public Class NativeStructs
    Public Structure MARGINS
        Public leftWidth As Integer
        Public rightWidth As Integer
        Public topHeight As Integer
        Public bottomHeight As Integer
    End Structure
End Class
Public Class NativeMethods
    <DllImport("dwmapi")> _
    Public Shared Function DwmExtendFrameIntoClientArea(ByVal hWnd As IntPtr, ByRef pMarInset As NativeStructs.MARGINS) As Integer
    End Function
    <DllImport("dwmapi")> _
    Friend Shared Function DwmSetWindowAttribute(ByVal hwnd As IntPtr, ByVal attr As Integer, ByRef attrValue As Integer, ByVal attrSize As Integer) As Integer
    End Function
    <DllImport("dwmapi.dll")> _
    Public Shared Function DwmIsCompositionEnabled(ByRef pfEnabled As Integer) As Integer
    End Function
End Class
Public Class NativeConstants
    Public Const CS_DROPSHADOW As Integer = &H20000
    Public Const WM_NCPAINT As Integer = &H85
End Class

Answer 4

我已经在这里回答了： Drop shadow on Borderless Winform-No flicker or消失

这是我的答案：

请尝试以下步骤并恢复任何错误：

将以下代码添加到名为 DropShadow.cs 的新代码文件中；

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Core
{
    public class DropShadow
    {
        #region Shadowing

        #region Fields

        private bool _isAeroEnabled = false;
        private bool _isDraggingEnabled = false;
        private const int WM_NCHITTEST = 0x84;
        private const int WS_MINIMIZEBOX = 0x20000;
        private const int HTCLIENT = 0x1;
        private const int HTCAPTION = 0x2;
        private const int CS_DBLCLKS = 0x8;
        private const int CS_DROPSHADOW = 0x00020000;
        private const int WM_NCPAINT = 0x0085;
        private const int WM_ACTIVATEAPP = 0x001C;

        #endregion

        #region Structures

        [EditorBrowsable(EditorBrowsableState.Never)]
        public struct MARGINS
        {
            public int leftWidth;
            public int rightWidth;
            public int topHeight;
            public int bottomHeight;
        }

        #endregion

        #region Methods

        #region Public

        [DllImport("dwmapi.dll")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public static extern int DwmExtendFrameIntoClientArea(IntPtr hWnd, ref MARGINS pMarInset);

        [DllImport("dwmapi.dll")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public static extern int DwmSetWindowAttribute(IntPtr hwnd, int attr, ref int attrValue, int attrSize);

        [DllImport("dwmapi.dll")]
        [EditorBrowsable(EditorBrowsableState.Never)]
        public static extern int DwmIsCompositionEnabled(ref int pfEnabled);

        [EditorBrowsable(EditorBrowsableState.Never)]
        public static bool IsCompositionEnabled()
        {
            if (Environment.OSVersion.Version.Major < 6) return false;

            bool enabled;
            DwmIsCompositionEnabled(out enabled);

            return enabled;
        }

        #endregion

        #region Private

        [DllImport("dwmapi.dll")]
        private static extern int DwmIsCompositionEnabled(out bool enabled);

        [DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
        private static extern IntPtr CreateRoundRectRgn
        (
            int nLeftRect,
            int nTopRect,
            int nRightRect,
            int nBottomRect,
            int nWidthEllipse,
            int nHeightEllipse
         );

        private bool CheckIfAeroIsEnabled()
        {
            if (Environment.OSVersion.Version.Major >= 6)
            {
                int enabled = 0;
                DwmIsCompositionEnabled(ref enabled);

                return (enabled == 1) ? true : false;
            }
            return false;
        }

        #endregion

        #region Overrides

        public void ApplyShadows(Form form)
        {
            var v = 2;

            DwmSetWindowAttribute(form.Handle, 2, ref v, 4);

            MARGINS margins = new MARGINS()
            {
                bottomHeight = 1,
                leftWidth = 0,
                rightWidth = 0,
                topHeight = 0
            };

            DwmExtendFrameIntoClientArea(form.Handle, ref margins);
        }

        #endregion

        #endregion

        #endregion
    }
}

在您的表单中，将此行添加到 InitializeComponent(); 下方

(new Core.DropShadow()).ApplyShadows(this);

不过，我还是建议切换到 WPF。很长一段时间以来，我自己都是 WinForms 的用户，但是 WPF 提供了比设计用户界面更好的灵活性。您还可以自己自定义所有控件，而无需任何框架或包。学习 WPF 确实需要一些时间，但这是值得的。

Answer 5

据我所知，在 WinForms 中没有直接的方法可以做到这一点。

相反，您可以逐步按照以下步骤操作：

1) 使用 Photoshop 或任何其他工具创建具有所需阴影的图像。
2) 将此图像用作表单的背景图像。
3) 将表单的 FormBorderStyle 属性设置为 None。
4）你完成了！
5) 注意：请务必以正确的格式（如 png）保存图像，以便投影效果生效。