我有这个类，我使用代码截取屏幕截图：
using System;
using System.Runtime.InteropServices;
using System.Drawing;
using System.Drawing.Imaging;
namespace WindowsFormsApplication1
{
/// <summary>
/// Provides functions to capture the entire screen, or a particular window, and save it to a file.
/// </summary>
public class ScreenCapture
{
/// <summary>
/// Creates an Image object containing a screen shot of the entire desktop
/// </summary>
/// <returns></returns>
public Image CaptureScreen()
{
return CaptureWindow(User32.GetDesktopWindow());
}
/// <summary>
/// Creates an Image object containing a screen shot of a specific window
/// </summary>
/// <param name="handle">The handle to the window. (In windows forms, this is obtained by the Handle property)</param>
/// <returns></returns>
public Image CaptureWindow(IntPtr handle)
{
// get te hDC of the target window
IntPtr hdcSrc = User32.GetWindowDC(handle);
// get the size
User32.RECT windowRect = new User32.RECT();
User32.GetWindowRect(handle, ref windowRect);
int width = windowRect.right - windowRect.left;
int height = windowRect.bottom - windowRect.top;
// create a device context we can copy to
IntPtr hdcDest = GDI32.CreateCompatibleDC(hdcSrc);
// create a bitmap we can copy it to,
// using GetDeviceCaps to get the width/height
IntPtr hBitmap = GDI32.CreateCompatibleBitmap(hdcSrc, width, height);
// select the bitmap object
IntPtr hOld = GDI32.SelectObject(hdcDest, hBitmap);
// bitblt over
GDI32.BitBlt(hdcDest, 0, 0, width, height, hdcSrc, 0, 0, GDI32.SRCCOPY);
// restore selection
GDI32.SelectObject(hdcDest, hOld);
// clean up
GDI32.DeleteDC(hdcDest);
User32.ReleaseDC(handle, hdcSrc);
// get a .NET image object for it
Image img = Image.FromHbitmap(hBitmap);
// free up the Bitmap object
GDI32.DeleteObject(hBitmap);
return img;
}
/// <summary>
/// Captures a screen shot of a specific window, and saves it to a file
/// </summary>
/// <param name="handle"></param>
/// <param name="filename"></param>
/// <param name="format"></param>
public void CaptureWindowToFile(IntPtr handle, string filename, ImageFormat format)
{
using (Image img = CaptureWindow(handle))
{
img.Save(filename, format);
}
}
/// <summary>
/// Captures a screen shot of the entire desktop, and saves it to a file
/// </summary>
/// <param name="filename"></param>
/// <param name="format"></param>
public void CaptureScreenToFile(string filename, ImageFormat format)
{
using (Image img = CaptureScreen())
{
img.Save(filename, format);
}
}
/// <summary>
/// Helper class containing Gdi32 API functions
/// </summary>
private class GDI32
{
public const int SRCCOPY = 0x00CC0020; // BitBlt dwRop parameter
[DllImport("gdi32.dll")]
public static extern bool BitBlt(IntPtr hObject, int nXDest, int nYDest,
int nWidth, int nHeight, IntPtr hObjectSource,
int nXSrc, int nYSrc, int dwRop);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleBitmap(IntPtr hDC, int nWidth,
int nHeight);
[DllImport("gdi32.dll")]
public static extern IntPtr CreateCompatibleDC(IntPtr hDC);
[DllImport("gdi32.dll")]
public static extern bool DeleteDC(IntPtr hDC);
[DllImport("gdi32.dll")]
public static extern bool DeleteObject(IntPtr hObject);
[DllImport("gdi32.dll")]
public static extern IntPtr SelectObject(IntPtr hDC, IntPtr hObject);
}
/// <summary>
/// Helper class containing User32 API functions
/// </summary>
private class User32
{
[StructLayout(LayoutKind.Sequential)]
public struct RECT
{
public int left;
public int top;
public int right;
public int bottom;
}
[DllImport("user32.dll")]
public static extern IntPtr GetDesktopWindow();
[DllImport("user32.dll")]
public static extern IntPtr GetWindowDC(IntPtr hWnd);
[DllImport("user32.dll")]
public static extern IntPtr ReleaseDC(IntPtr hWnd, IntPtr hDC);
[DllImport("user32.dll")]
public static extern IntPtr GetWindowRect(IntPtr hWnd, ref RECT rect);
}
}
}
然后我创建了一个新课程，我正在使用AviFile从屏幕截图中实时创建avi电影文件：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using AviFile;
using System.Drawing;
namespace WindowsFormsApplication1
{
class ScreenshotsToAvi
{
int count = 0;
VideoStream aviStream;
AviManager aviManager;
Bitmap bmp;
public ScreenshotsToAvi()
{
aviManager = new AviManager(@"d:\testdata\new.avi", false);
}
public void CreateAvi(ScreenCapture sc)
{
bmp = new Bitmap(sc.CaptureScreen());
count++;
if (count == 1)
{
aviStream = aviManager.AddVideoStream(false, 25, bmp);
}
aviStream.AddFrame(bmp);
bmp.Dispose();
}
public AviManager avim
{
get
{
return aviManager;
}
set
{
aviManager = value;
}
}
}
}
然后在形式中我使用它：
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
ScreenshotsToAvi screens2avi;
int count;
ScreenCapture sc;
public Form1()
{
InitializeComponent();
screens2avi = new ScreenshotsToAvi();
label2.Text = "0";
count = 0;
sc = new ScreenCapture();
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void timer1_Tick(object sender, EventArgs e)
{
count++;
sc.CaptureScreen();
screens2avi.CreateAvi(this.sc);
label2.Text = count.ToString();
}
private void button1_Click(object sender, EventArgs e)
{
timer1.Enabled = true;
}
private void button2_Click(object sender, EventArgs e)
{
timer1.Enabled = false;
screens2avi.avim.Close();
}
private void button3_Click(object sender, EventArgs e)
{
timer1.Enabled = false;
string[] filePaths = Directory.GetFiles(@"c:\temp\screens7\");
foreach (string filePath in filePaths)
File.Delete(filePath);
label2.Text = "0";
}
}
}
在程序运行一两分钟后，它进入ScreenShotsToAvi类并在此行抛出异常：
bmp = new Bitmap(sc.CaptureScreen());
内存不足
System.OutOfMemoryException was unhandled
HResult=-2147024882
Message=Out of memory.
Source=System.Drawing
StackTrace:
at System.Drawing.Graphics.CheckErrorStatus(Int32 status)
at System.Drawing.Graphics.DrawImage(Image image, Int32 x, Int32 y, Int32 width, Int32 height)
at System.Drawing.Bitmap..ctor(Image original, Int32 width, Int32 height)
at System.Drawing.Bitmap..ctor(Image original)
at WindowsFormsApplication1.ScreenshotsToAvi.CreateAvi(ScreenCapture sc) in d:\C-Sharp\ReadWriteToMemory\WindowsFormsApplication1\WindowsFormsApplication1\ScreenshotsToAvi.cs:line 26
at WindowsFormsApplication1.Form1.timer1_Tick(Object sender, EventArgs e) in d:\C-Sharp\ReadWriteToMemory\WindowsFormsApplication1\WindowsFormsApplication1\Form1.cs:line 41
at System.Windows.Forms.Timer.OnTick(EventArgs e)
at System.Windows.Forms.Timer.TimerNativeWindow.WndProc(Message& m)
at System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
at System.Windows.Forms.UnsafeNativeMethods.DispatchMessageW(MSG& msg)
at System.Windows.Forms.Application.ComponentManager.System.Windows.Forms.UnsafeNativeMethods.IMsoComponentManager.FPushMessageLoop(IntPtr dwComponentID, Int32 reason, Int32 pvLoopData)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
at System.Windows.Forms.Application.Run(Form mainForm)
at WindowsFormsApplication1.Program.Main() in d:\C-Sharp\ReadWriteToMemory\WindowsFormsApplication1\WindowsFormsApplication1\Program.cs:line 19
at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
at System.Threading.ThreadHelper.ThreadStart()
InnerException:
我再一次处理bmp所以为什么异常即将到来？我是否还需要处理其他任何事情？
public void CreateAvi(ScreenCapture sc)
{
bmp = new Bitmap(sc.CaptureScreen());
count++;
if (count == 1)
{
aviStream = aviManager.AddVideoStream(false, 25, bmp);
}
aviStream.AddFrame(bmp);
bmp.Dispose();
}
答案 0 :(得分：3)
bmp = new Bitmap(sc.CaptureScreen());
这是一个大红旗。我假设CaptureScreen（）方法返回一个Image或Bitmap对象。然后你出于某种原因制作了副本。并且只处理副本，您不会丢弃CaptureScreen（）返回的原始图像。
这不会持续很长时间。
假设你确实需要副本（我不知道为什么），你必须这样写：
using (var img = sc.CaptureScreen())
using (var bmp = new Bitmap(img)) {
// etc..
}
很少有Image对象实际上不是Bitmap。只有一个图元文件可能是另一种风格，你不会从屏幕截图中得到一个。所以请尝试：
using (var bmp = (Bitmap)sc.CaptureScreen()) {
// etc..
}
在任务管理器中查看进程的VM大小，以验证您的内存使用情况现在相当稳定且不再爆炸。你想看到它快速增加，然后随着程序的运行而上下跳动。如果AVI编码器不直接将avi数据流式传输到文件，那么AVI编码器也可能是资源占用者。如果需要太多内存，可能需要切换到64位代码。在任务管理器中添加GDI对象列，它可靠地告诉您是否仍在泄漏位图对象。