我想創建一個倒計時計時器，它顯示在螢屏的右下方，帶有略微透明的文本，無論螢屏上有什么都可以看到。想想當您的 windows 副本未激活時出現的 windows 未激活水印訊息。它顯示在右下方，覆寫所有視窗，并“卡在”螢屏上。
有沒有辦法通程序式做到這一點？首選 C#。
到目前為止，在我的研究中，我只遇到過 Deskbands，它可以讓你在任務欄中放一些東西，但不能放在它之外。
uj5u.com熱心網友回復：
注意：以下答案創建了一個邊緣平滑的正常半透明最頂層形式。它與視窗激活文本不完全一樣，例如它位于工具提示視窗或選單后面，但它位于其他非最頂層視窗的頂部。
您可以通過設定
例子
在以下示例中，我創建了一個始終位于頂部并顯示時間的疊加表單：
1 - 將以下包含所需本機方法的類添加到您的專案中：
using System;
using System.Runtime.InteropServices;
public class NativeMethods
{
public const int WS_EX_LAYERED = 0x80000;
public const int HTCAPTION = 0x02;
public const int WM_NCHITTEST = 0x84;
public const int ULW_ALPHA = 0x02;
public const byte AC_SRC_OVER = 0x00;
public const byte AC_SRC_ALPHA = 0x01;
public const int WS_EX_TRANSPARENT = 0x20;
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public int x;
public int y;
public POINT(int x, int y)
{ this.x = x; this.y = y; }
}
[StructLayout(LayoutKind.Sequential)]
public struct SIZE
{
public int cx;
public int cy;
public SIZE(int cx, int cy)
{ this.cx = cx; this.cy = cy; }
}
[StructLayout(LayoutKind.Sequential, Pack = 1)]
public struct BLENDFUNCTION
{
public byte BlendOp;
public byte BlendFlags;
public byte SourceConstantAlpha;
public byte AlphaFormat;
}
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool UpdateLayeredWindow(IntPtr hwnd, IntPtr hdcDst,
ref POINT pptDst, ref SIZE psize, IntPtr hdcSrc, ref POINT pprSrc,
int crKey, ref BLENDFUNCTION pblend, int dwFlags);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr GetDC(IntPtr hWnd);
[DllImport("user32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern int ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool DeleteDC(IntPtr hdc);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
[DllImport("gdi32.dll", CharSet = CharSet.Auto, SetLastError = true)]
[return: MarshalAs(UnmanagedType.Bool)]
public static extern bool DeleteObject(IntPtr hObject);
}
2 - 添加以下類，它是半透明平滑邊緣視窗表單的基類：
using System;
using System.Drawing;
using System.Windows.Forms;
using System.Drawing.Imaging;
using static NativeMethods;
public class PerPixelAlphaForm : Form
{
public PerPixelAlphaForm()
{
this.FormBorderStyle = FormBorderStyle.None;
this.ShowInTaskbar = false;
this.TopMost = true;
}
protected override CreateParams CreateParams
{
get
{
CreateParams createParams = base.CreateParams;
if (!DesignMode)
createParams.ExStyle |= WS_EX_LAYERED | WS_EX_TRANSPARENT;
return createParams;
}
}
public void SelectBitmap(Bitmap bitmap, int opacity = 255)
{
if (bitmap.PixelFormat != PixelFormat.Format32bppArgb)
{
throw new ApplicationException(
"The bitmap must be 32bpp with alpha-channel.");
}
IntPtr screenDc = GetDC(IntPtr.Zero);
IntPtr memDc = CreateCompatibleDC(screenDc);
IntPtr hBitmap = IntPtr.Zero;
IntPtr hOldBitmap = IntPtr.Zero;
try
{
hBitmap = bitmap.GetHbitmap(Color.FromArgb(0));
hOldBitmap = SelectObject(memDc, hBitmap);
SIZE newSize = new SIZE(bitmap.Width, bitmap.Height);
POINT sourceLocation = new POINT(0, 0);
POINT newLocation = new POINT(this.Left, this.Top);
BLENDFUNCTION blend = new BLENDFUNCTION();
blend.BlendOp = AC_SRC_OVER;
blend.BlendFlags = 0;
blend.SourceConstantAlpha = (byte)opacity;
blend.AlphaFormat = AC_SRC_ALPHA;
UpdateLayeredWindow(this.Handle, screenDc, ref newLocation,
ref newSize, memDc, ref sourceLocation, 0, ref blend, ULW_ALPHA);
}
finally
{
ReleaseDC(IntPtr.Zero, screenDc);
if (hBitmap != IntPtr.Zero)
{
SelectObject(memDc, hOldBitmap);
DeleteObject(hBitmap);
}
DeleteDC(memDc);
}
}
}
3 - 然后添加以下類，它是一個表單，有一個顯示時間的計時器：
using System;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;
using System.Windows.Forms;
public partial class Form1 : PerPixelAlphaForm
{
private IContainer components = null;
private Timer timer1;
private Bitmap image;
public Form1()
{
this.components = new Container();
this.timer1 = new Timer(this.components);
this.timer1.Enabled = true;
this.timer1.Interval = 500;
this.timer1.Tick = new EventHandler(this.timer1_Tick);
this.StartPosition = FormStartPosition.Manual;
this.Location = new Point(300, 300);
this.Size = new Size(800, 500);
this.image = new Bitmap(Width, Height, PixelFormat.Format32bppArgb);
}
private void timer1_Tick(object sender, EventArgs e)
{
using (var g = Graphics.FromImage(image))
{
g.Clear(Color.Transparent);
g.SmoothingMode = SmoothingMode.AntiAlias;
g.TextRenderingHint = TextRenderingHint.AntiAlias;
g.DrawString(DateTime.Now.ToString("HH:mm:ss"),
new Font(this.Font.FontFamily, 60, FontStyle.Bold), Brushes.Black,
ClientRectangle, StringFormat.GenericDefault);
SelectBitmap(image, 150);
}
}
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
components.Dispose();
if (disposing && image != null)
image.Dispose();
base.Dispose(disposing);
}
}
您可以在以下帖子中找到更多資訊：
- Windows 表單：通過部分透明的始終位于頂部的視窗傳遞點擊
- 表格的透明背景影像 - 表格的平滑邊緣形狀
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