如何使用Win32 'DwmSetIconicThumbnail‘来自C#还是VB.Net？开发者社区

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Bitmap bmp;
IntPtr hBitmap;
IntPtr hwnd;
int hresult;
const int DisplayThumbnailFrame = 0x1;
public enum DwmWindowAttribute : uint
    NcRenderingEnabled = 1,
    NcRenderingPolicy,
    TransitionsForceDisabled,
    AllowNcPaint,
    CaptionButtonBounds,
    NonClientRtlLayout,
    ForceIconicRepresentation,
    Flip3DPolicy,
    ExtendedFrameBounds,
    HasIconicBitmap,
    DisallowPeek,
    ExcludedFromPeek,
    Cloak,
    Cloaked,
    FreezeRepresentation,
[DllImport("dwmapi.dll", PreserveSig = true)]
static internal extern int DwmSetWindowAttribute(IntPtr hwnd, 
                                                 DwmWindowAttribute dwAttributeToSet, 
                                                 IntPtr pvAttributeValue, 
                                                 uint cbAttribute);
[DllImport("Dwmapi.dll")]
public static extern int DwmSetIconicThumbnail(IntPtr hwnd, 
                                               IntPtr hBitmap, 
                                               int flags);
private void Form1_Shown() {
    bmp = (Bitmap)Bitmap.FromFile("C:\\Image.jpg");
    hBitmap = bmp.GetHbitmap();
    hwnd = Process.GetCurrentProcess.MainWindowHandle;
    IntPtr block = Marshal.AllocHGlobal(4);
    int value = Math.Abs(Convert.ToInt32(true)); // or 1
    Marshal.WriteInt32(block, value);
    try {
        hresult = DwmSetWindowAttribute(hwnd, DwmWindowAttribute.HasIconicBitmap, block, 4);
        if ((hresult != 0)) {
            throw Marshal.GetExceptionForHR(hresult);
        hresult = DwmSetWindowAttribute(hwnd, DwmWindowAttribute.ForceIconicRepresentation, block, 4);
        if ((hresult != 0)) {
            throw Marshal.GetExceptionForHR(hresult);
    } finally {
        Marshal.FreeHGlobal(block);
    hresult = DwmSetIconicThumbnail(hwnd, hBitmap, DisplayThumbnailFrame);
    if ((hresult != 0)) {
        throw Marshal.GetExceptionForHR(hresult);
}

Dim bmp As Bitmap
Dim hBitmap As IntPtr
Dim hwnd As IntPtr
Dim hresult As Integer
Const DisplayThumbnailFrame As Integer = &H1
Enum DwmWindowAttribute As UInteger
    NcRenderingEnabled = 1
    NcRenderingPolicy
    TransitionsForceDisabled
    AllowNcPaint
    CaptionButtonBounds
    NonClientRtlLayout
    ForceIconicRepresentation
    Flip3DPolicy
    ExtendedFrameBounds
    HasIconicBitmap
    DisallowPeek
    ExcludedFromPeek
    Cloak
    Cloaked
    FreezeRepresentation
End Enum
<DllImport("dwmapi.dll", PreserveSig:=True)>
Friend Shared Function DwmSetWindowAttribute(hwnd As IntPtr,
                                             dwAttributeToSet As DwmWindowAttribute,
                                             pvAttributeValue As IntPtr,
                                             cbAttribute As UInteger
) As Integer
End Function
<DllImport("Dwmapi.dll")>
Public Shared Function DwmSetIconicThumbnail(ByVal hwnd As IntPtr,
                                             ByVal hBitmap As IntPtr,
                                             ByVal flags As Integer
) As Integer
End Function
Private Sub Form1_Shown() Handles MyBase.Shown
    bmp = DirectCast(Bitmap.FromFile("C:\Image.jpg"), Bitmap)
    hBitmap = bmp.GetHbitmap()
    hwnd = Process.GetCurrentProcess.MainWindowHandle
    Dim block As IntPtr = Marshal.AllocHGlobal(4)
    Dim value As Integer = Math.Abs(CInt(True)) ' or 1
    Marshal.WriteInt32(block, value)
        hresult = DwmSetWindowAttribute(hwnd, DwmWindowAttribute.HasIconicBitmap, block, 4)
        If (hresult <> 0) Then
            Throw Marshal.GetExceptionForHR(hresult)
        End If
        hresult = DwmSetWindowAttribute(hwnd, DwmWindowAttribute.ForceIconicRepresentation, block, 4)
        If (hresult <> 0) Then
            Throw Marshal.GetExceptionForHR(hresult)
        End If
    Finally
        Marshal.FreeHGlobal(block)
    End Try
    hresult = DwmSetIconicThumbnail(hwnd, hBitmap, DisplayThumbnailFrame)
    If (hresult <> 0) Then
        Throw Marshal.GetExceptionForHR(hresult)
    End If
End Sub

Private Const WM_DWMSENDICONICTHUMBNAIL As Integer = &H323
Protected Overrides Sub WndProc(ByRef m As Windows.Forms.Message)
    Select Case m.Msg
        Case WM_DWMSENDICONICTHUMBNAIL
            Dim hwnd As IntPtr = Process.GetCurrentProcess().MainWindowHandle
            Dim dWord As Integer = m.LParam.ToInt32()
            Dim maxWidth As Short = BitConverter.ToInt16(BitConverter.GetBytes(dWord), 2)
            Dim maxHeight As Short = BitConverter.ToInt16(BitConverter.GetBytes(dWord), 0)
            Using img As Image = Bitmap.FromFile("C:\Image.jpg")
                Using thumb As Bitmap = CType(img.GetThumbnailImage(maxWidth, maxHeight, Nothing, Nothing), Bitmap)
                    Dim hBitmap As IntPtr = thumb.GetHbitmap()
                    Dim hresult As Integer = NativeMethods.DwmSetIconicThumbnail(hwnd, hBitmap, 0)
                    If (hresult <> 0) Then
                        ' Handle error...
                        ' Throw Marshal.GetExceptionForHR(hresult)
                    End If
                    NativeMethods.DeleteObject(hBitmap)
                End Using
            End Using
    End Select
    ' Return Message to base message handler.
    MyBase.WndProc(m)
End Sub

internal static class NativeMethods
    [DllImport("dwmapi.dll")]
    public static extern int DwmSetIconicThumbnail(IntPtr hwnd, IntPtr hbmp, DWM_SIT dwSITFlags);
    [DllImport("dwmapi.dll")]
    public static extern int DwmSetWindowAttribute(IntPtr hwnd, DWMWA dwAttribute, ref int pvAttribute, int cbAttribute);
    public enum DWM_SIT
        None,
        DISPLAYFRAME = 1
    public enum DWMWA
        NCRENDERING_ENABLED = 1,
        NCRENDERING_POLICY,
        TRANSITIONS_FORCEDISABLED,
        ALLOW_NCPAINT,
        CAPTION_BUTTON_BOUNDS,
        NONCLIENT_RTL_LAYOUT,
        FORCE_ICONIC_REPRESENTATION,
        FLIP3D_POLICY,
        EXTENDED_FRAME_BOUNDS,
        // New to Windows 7:
        HAS_ICONIC_BITMAP,
        DISALLOW_PEEK,
        EXCLUDED_FROM_PEEK
        // LAST
    public const uint TRUE = 1;
}

    private void Form1_Shown(object sender, EventArgs e)
        bmp = (Bitmap)Bitmap.FromFile("C:\\Image.jpg");
        hBitmap = bmp.GetHbitmap();
        hwnd = Process.GetCurrentProcess().MainWindowHandle;
        int attributeTrue = (int)NativeMethods.TRUE;
        hresult = NativeMethods.DwmSetWindowAttribute(hwnd, NativeMethods.DWMWA.HAS_ICONIC_BITMAP, ref attributeTrue, sizeof(int));
        if ((hresult != 0))
            throw Marshal.GetExceptionForHR(hresult);
        hresult = NativeMethods.DwmSetWindowAttribute(hwnd, NativeMethods.DWMWA.FORCE_ICONIC_REPRESENTATION, ref attributeTrue, sizeof(int));
        if ((hresult != 0))
            throw Marshal.GetExceptionForHR(hresult);
        hresult = NativeMethods.DwmSetIconicThumbnail(hwnd, hBitmap, NativeMethods.DWM_SIT.DISPLAYFRAME);
        if ((hresult != 0))
            throw Marshal.GetExceptionForHR(hresult);

问 如何使用Win32 'DwmSetIconicThumbnail‘来自C#还是VB.Net？ EN

回答 3

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