如何在Windows 8.1中获取MessageBox图标

Question

我想获得MessageBoxIcons,当用户出现时会显示MessageBox.早些时候我为此目的使用了SystemIcons,但现在它似乎返回的图标不同于MessageBox.

这导致了在Windows 8.1中SystemIcons和MessageBoxIcons不同的结论.我知道使用WinApi MessageBox获取图标,但我似乎无法以任何方式获取图标.

我想问一种检索这些图标的方法.

Answer 1

更新:

你应该使用这个SHGetStockIconInfo功能.

要在C#中执行此操作,您必须定义一些枚举和结构(有关更多信息,请参阅此优秀页面):

public enum SHSTOCKICONID : uint
{
    //...
    SIID_INFO = 79,
    //...
}

[Flags]
public enum SHGSI : uint
{
    SHGSI_ICONLOCATION = 0,
    SHGSI_ICON = 0x000000100,
    SHGSI_SYSICONINDEX = 0x000004000,
    SHGSI_LINKOVERLAY = 0x000008000,
    SHGSI_SELECTED = 0x000010000,
    SHGSI_LARGEICON = 0x000000000,
    SHGSI_SMALLICON = 0x000000001,
    SHGSI_SHELLICONSIZE = 0x000000004
}

[StructLayoutAttribute(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
public struct SHSTOCKICONINFO
{
    public UInt32 cbSize;
    public IntPtr hIcon;
    public Int32 iSysIconIndex;
    public Int32 iIcon;
    [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260/*MAX_PATH*/)]
    public string szPath;
}

[DllImport("Shell32.dll", SetLastError = false)]
public static extern Int32 SHGetStockIconInfo(SHSTOCKICONID siid, SHGSI uFlags, ref SHSTOCKICONINFO psii);

之后,您可以轻松获得所需的图标:

 SHSTOCKICONINFO sii = new SHSTOCKICONINFO();
 sii.cbSize = (UInt32)Marshal.SizeOf(typeof(SHSTOCKICONINFO));

 Marshal.ThrowExceptionForHR(SHGetStockIconInfo(SHSTOCKICONID.SIID_INFO,
         SHGSI.SHGSI_ICON ,
         ref sii));
 pictureBox1.Image = Icon.FromHandle(sii.hIcon).ToBitmap();

这是结果的样子:

请注意:

如果此函数返回psii指向的SHSTOCKICONINFO结构的hIcon成员中的 图标句柄,则您负责在不再需要时使用DestroyIcon释放该图标.

我不会删除我的原始答案,因为 - 我认为 - 它包含有关此问题的有用信息,以及检索此图标的另一种方法(或解决方法).

原始答案:

相当有趣的图标呈现在SystemIcons从所显示的那些不同MessageBoxes的的情况下Asterisk,Information和Question.对话框上的图标看起来更平坦.

在所有其他情况下,它们看起来完全相同,例如:在以下情况下Error:

当您尝试使用图标获取图标时,SystemIcons您将获得上图中左侧的图标.

// get icon from SystemIcons
pictureBox1.Image = SystemIcons.Asterisk.ToBitmap();

如果您尝试使用LoadIconuser32.dll中的方法稍微努力一点,您仍然可以获得相同的图标(在上图中可以看到).

[DllImport("user32.dll")]
static extern IntPtr LoadIcon(IntPtr hInstance, IntPtr lpIconName);

...

public enum SystemIconIds
{
    ...
    IDI_ASTERISK = 32516,
    ...
}

...

// load icon by ID
IntPtr iconHandle = LoadIcon(IntPtr.Zero, new IntPtr((int)SystemIconIds.IDI_ASTERISK));
pictureBox2.Image = Icon.FromHandle(iconHandle).ToBitmap();

但是当你展示一个MessagBox时,你得到一个不同的(如图中所示MessageBox).一个人别无选择,只能从中得到那个图标MessageBox.

为此我们需要更多的DllImports:

// To be able to find the dialog window
[DllImport("user32.dll", SetLastError = true)]
static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

// To be able to get the icon window handle
[DllImport("user32.dll")]
static extern IntPtr GetDlgItem(IntPtr hDlg, int nIDDlgItem);

// To be able to get a handle to the actual icon
[DllImport("user32.dll", CharSet = CharSet.Auto)]
static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

这个想法如下:首先我们显示一个MessageBox,之后(当它仍然显示时)我们发现它的句柄,使用该句柄我们将得到另一个句柄,现在到包含图标的静态控件.最后,我们将向该控件发送一条消息(一条STM_GETICON消息),该消息将返回一个图标本身的句柄.使用该句柄我们可以创建一个Icon,我们可以在我们的应用程序的任何地方使用.

在代码中:

// show a `MessageBox`
MessageBox.Show("test", "test caption", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);

...

var hwnd = FindWindow(null, "test caption");
if (hwnd != IntPtr.Zero)
{
    // we got the messagebox, get the icon from it
    IntPtr hIconWnd = GetDlgItem(hwnd, 20);
    if (hIconWnd != IntPtr.Zero)
    {
        var iconHandle = SendMessage(hIconWnd, 369/*STM_GETICON*/, IntPtr.Zero, IntPtr.Zero);

        pictureBox3.Image = Icon.FromHandle(iconHandle).ToBitmap();
    }
}

代码运行后,PictureBox被调用的pictureBox3将显示与图像相同的图像MessageBox(如图中右侧所示).

我真的希望这会有所帮助.

这里是所有代码的参考(它是一个WinForms应用程序,Form有三个PicturBoxes和一个Timer,它们的名字可以从代码中扣除......):

using System;
using System.Drawing;
using System.Runtime.InteropServices;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        [DllImport("user32.dll")]
        static extern IntPtr LoadIcon(IntPtr hInstance, IntPtr lpIconName);

        [DllImport("user32.dll", SetLastError = true)]
        static extern IntPtr FindWindow(string lpClassName, string lpWindowName);

        [DllImport("user32.dll")]
        static extern IntPtr GetDlgItem(IntPtr hDlg, int nIDDlgItem);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        static extern IntPtr SendMessage(IntPtr hWnd, UInt32 Msg, IntPtr wParam, IntPtr lParam);

        public enum SystemIconIds
        {
            IDI_APPLICATION = 32512,
            IDI_HAND = 32513,
            IDI_QUESTION = 32514,
            IDI_EXCLAMATION = 32515,
            IDI_ASTERISK = 32516,
            IDI_WINLOGO = 32517,
            IDI_WARNING = IDI_EXCLAMATION,
            IDI_ERROR = IDI_HAND,
            IDI_INFORMATION = IDI_ASTERISK,
        }

        public Form1()
        {
            InitializeComponent();
            // Information, Question and Asterix differ from the icons displayed on MessageBox

            // get icon from SystemIcons
            pictureBox1.Image = SystemIcons.Asterisk.ToBitmap();
            // load icon by ID
            IntPtr iconHandle = LoadIcon(IntPtr.Zero, new IntPtr((int)SystemIconIds.IDI_ASTERISK));
            pictureBox2.Image = Icon.FromHandle(iconHandle).ToBitmap();
        }

        private void pictureBox1_Click(object sender, EventArgs e)
        {
            MessageBox.Show("test", "test caption", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
        }


        private void timer1_Tick(object sender, EventArgs e)
        {
            var hwnd = FindWindow(null, "test caption");
            if (hwnd != IntPtr.Zero)
            {
                // we got the messagebox, get the icon from it
                IntPtr hIconWnd = GetDlgItem(hwnd, 20);
                if (hIconWnd != IntPtr.Zero)
                {
                    var iconHandle = SendMessage(hIconWnd, 369/*STM_GETICON*/, IntPtr.Zero, IntPtr.Zero);
                    pictureBox3.Image = Icon.FromHandle(iconHandle).ToBitmap();
                }
            }
        }
    }
}