生成缩略图时内存不足

Question

windows应用程序 代码如下  本来是要写成windows服务的
先用应用程序测试一下。
大概是写一个文件夹监控程序，一旦文件夹中有图片类文件操作，则在另一个文件夹的对应路径下生成此图的缩略图。
问题：在调试的时候，不会报错，功能全部都有。
但是，在执行的时候，只要在监视的图片中拷贝一张图片进去，就会报错，提示内存不足。虚心请教原因。
补充：生成缩略图的方法是网上找的，还换过方法，都是一样的症状。
开发环境  vs2008 sp1
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Drawing.Imaging;
using System.Threading;namespace WindowsTest
{
    public partial class entry : Form
    {
        public entry()
        {
            InitializeComponent();
        }
        #region 按钮事件
        /// <summary>
        /// 退出应用程序
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonExit_Click(object sender, EventArgs e)
        {
            Application.Exit();//退出应用程序
        }
        /// <summary>
        /// 选择原路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonSearchOld_Click(object sender, EventArgs e)
        {
            this.folderBrowserDialogOldPatch.ShowNewFolderButton = true;
            this.folderBrowserDialogOldPatch.ShowDialog();
            this.textBoxOldPath.Text = this.folderBrowserDialogOldPatch.SelectedPath;
        }
        /// <summary>
        /// 选择新路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonSearchNew_Click(object sender, EventArgs e)
        {
            this.folderBrowserDialogOldPatch.ShowNewFolderButton = true;
            this.folderBrowserDialogNewPath.ShowDialog();
            this.textBoxNewPath.Text = this.folderBrowserDialogNewPath.SelectedPath;
        }
        /// <summary>
        /// 开始监控原文件夹
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonAutoWatcher_Click(object sender, EventArgs e)
        {
            if (this.textBoxNewPath.Text.Trim() == string.Empty)
            {
                MessageBox.Show("请选择目标路径", "错误：目标路径为空", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            if (this.textBoxOldPath.Text.Trim() == string.Empty)
            {
                MessageBox.Show("请选择原路径", "错误：原路径为空", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            if (this.buttonAutoWatcher.Text == "自动")
            {
                this.buttonAutoWatcher.Text = "停止";
                this.SetEnable(false);
                this.StartWatcher();
            }
            else
            {
                this.buttonAutoWatcher.Text = "自动";
                this.SetEnable(true);
            }
        }
        #endregion        #region 自定义方法
        /// <summary>
        /// 设定按钮的是否可用
        /// </summary>
        /// <param name="s">是否可用</param>
        private void SetEnable(bool s)
        {
            this.buttonSearchNew.Enabled = s;
            this.buttonSearchOld.Enabled = s;
            this.textBoxNewPath.Enabled = s;
            this.textBoxOldPath.Enabled = s;
            this.checkBoxIncludeSub.Enabled = s;
        }
        private void StartWatcher()
        {
            fw.BeginInit();
            fw.IncludeSubdirectories = this.checkBoxIncludeSub.Checked;//是否包含子文件夹
            fw.Path = this.textBoxOldPath.Text;
            fw.Changed += new System.IO.FileSystemEventHandler(OnChanged);
            fw.Created += new System.IO.FileSystemEventHandler(OnCreated);
            fw.Renamed += new System.IO.RenamedEventHandler(OnRenamed);
            fw.Deleted += new System.IO.FileSystemEventHandler(OnDeleted);
            fw.EnableRaisingEvents = true;
            fw.EndInit();
        }        void OnDeleted(object sender, System.IO.FileSystemEventArgs e)
        {
        }        void OnRenamed(object sender, System.IO.RenamedEventArgs e)
        {
        }        void OnCreated(object sender, System.IO.FileSystemEventArgs e)
        {
            string NewPath = e.FullPath;
            NewPath = NewPath.Replace(this.textBoxOldPath.Text.Trim(), this.textBoxNewPath.Text);
            this.CreateFile(e.FullPath, NewPath);
        }        void OnChanged(object sender, System.IO.FileSystemEventArgs e)
        {
        }        /// <summary>
        /// 生成新的文件
        /// </summary>
        /// <param name="ol">原图片路径</param>
        /// <param name="ne">新图片路径</param>
        /// <returns></returns>
        private void CreateFile(string ol, string ne)
        {
            if (File.Exists(ol))
            {
                if (!Directory.Exists(ne.Substring(0, ne.LastIndexOf('\\'))))
                {
                    Directory.CreateDirectory(ne.Substring(0, ne.LastIndexOf('\\')));
                }
                string exFileName= ol.Substring(ol.LastIndexOf('.')).ToLower();
                if (exFileName == ".jpg" || exFileName == ".gif" || exFileName == ".bmp"||exFileName==".jpeg"||exFileName==".png")
                {
                    this.ShowThumbnail(ol, ne,Convert.ToInt32(numericUpDownHeight.Value),Convert.ToInt32(numericUpDownWidth.Value));
                }
            }
        }
        public void ShowThumbnail(string oldfile, string newfile, int h, int w)
        {            System.Drawing.Image img = System.Drawing.Image.FromFile(oldfile);
            System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);            int oldh = img.Height;
            int oldw = img.Width;            int newh, neww;            double h1 = oldh * 1.0 / h;
            double w1 = oldw * 1.0 / w;            double f = (h1 > w1) ? h1 : w1;            if (f < 1.0)
            {
                newh = oldh;
                neww = oldw;
            }
            else
            {
                newh = (int)(oldh / f);
                neww = (int)(oldw / f);
            }            System.Drawing.Image myThumbnail = img.GetThumbnailImage(neww, newh, myCallback, IntPtr.Zero);
            string exFileName = oldfile.Substring(oldfile.LastIndexOf('.')+1).ToLower();
            switch (exFileName)
            {
                case "jpg":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
                case "bmp":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Bmp);
                    break;
                case "jpeg":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
                case "gif":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Gif);
                    break;
                case "png":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Png);
                    break;
                default:
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
            }
            
            img.Dispose();
            myThumbnail.Dispose();
        }
        private static bool ThumbnailCallback()
        {
            return false;
        }           #endregion
    }
}

Answer 1

试试加锁。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Drawing.Imaging;
using System.Threading;namespace WindowsTest
{
    public partial class entry : Form
    {
        private static Object lockObj = new object();        public entry()
        {
            InitializeComponent();
        }
        #region 按钮事件
        /// <summary>
        /// 退出应用程序
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonExit_Click(object sender, EventArgs e)
        {
            Application.Exit();//退出应用程序
        }
        /// <summary>
        /// 选择原路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonSearchOld_Click(object sender, EventArgs e)
        {
            this.folderBrowserDialogOldPatch.ShowNewFolderButton = true;
            this.folderBrowserDialogOldPatch.ShowDialog();
            this.textBoxOldPath.Text = this.folderBrowserDialogOldPatch.SelectedPath;
        }
        /// <summary>
        /// 选择新路径
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonSearchNew_Click(object sender, EventArgs e)
        {
            this.folderBrowserDialogOldPatch.ShowNewFolderButton = true;
            this.folderBrowserDialogNewPath.ShowDialog();
            this.textBoxNewPath.Text = this.folderBrowserDialogNewPath.SelectedPath;
        }
        /// <summary>
        /// 开始监控原文件夹
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void buttonAutoWatcher_Click(object sender, EventArgs e)
        {
            if (this.textBoxNewPath.Text.Trim() == string.Empty)
            {
                MessageBox.Show("请选择目标路径", "错误：目标路径为空", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            if (this.textBoxOldPath.Text.Trim() == string.Empty)
            {
                MessageBox.Show("请选择原路径", "错误：原路径为空", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            if (this.buttonAutoWatcher.Text == "自动")
            {
                this.buttonAutoWatcher.Text = "停止";
                this.SetEnable(false);
                this.StartWatcher();
            }
            else
            {
                this.buttonAutoWatcher.Text = "自动";
                this.SetEnable(true);
            }
        }
        #endregion        #region 自定义方法
        /// <summary>
        /// 设定按钮的是否可用
        /// </summary>
        /// <param name="s">是否可用</param>
        private void SetEnable(bool s)
        {
            this.buttonSearchNew.Enabled = s;
            this.buttonSearchOld.Enabled = s;
            this.textBoxNewPath.Enabled = s;
            this.textBoxOldPath.Enabled = s;
            this.checkBoxIncludeSub.Enabled = s;
        }
        private void StartWatcher()
        {
            fw.BeginInit();
            fw.IncludeSubdirectories = this.checkBoxIncludeSub.Checked;//是否包含子文件夹
            fw.Path = this.textBoxOldPath.Text;
            fw.Changed += new System.IO.FileSystemEventHandler(OnChanged);
            fw.Created += new System.IO.FileSystemEventHandler(OnCreated);
            fw.Renamed += new System.IO.RenamedEventHandler(OnRenamed);
            fw.Deleted += new System.IO.FileSystemEventHandler(OnDeleted);
            fw.EnableRaisingEvents = true;
            fw.EndInit();
        }        void OnDeleted(object sender, System.IO.FileSystemEventArgs e)
        {
        }        void OnRenamed(object sender, System.IO.RenamedEventArgs e)
        {
        }        void OnCreated(object sender, System.IO.FileSystemEventArgs e)
        {
            string NewPath = e.FullPath;
            NewPath = NewPath.Replace(this.textBoxOldPath.Text.Trim(), this.textBoxNewPath.Text);
            this.CreateFile(e.FullPath, NewPath);
        }        void OnChanged(object sender, System.IO.FileSystemEventArgs e)
        {
        }        /// <summary>
        /// 生成新的文件
        /// </summary>
        /// <param name="ol">原图片路径</param>
        /// <param name="ne">新图片路径</param>
        /// <returns></returns>
        private void CreateFile(string ol, string ne)
        {
            if (File.Exists(ol))
            {
                if (!Directory.Exists(ne.Substring(0, ne.LastIndexOf('\\'))))
                {
                    Directory.CreateDirectory(ne.Substring(0, ne.LastIndexOf('\\')));
                }
                string exFileName= ol.Substring(ol.LastIndexOf('.')).ToLower();
                if (exFileName == ".jpg" || exFileName == ".gif" || exFileName == ".bmp"||exFileName==".jpeg"||exFileName==".png")
                {
                    this.ShowThumbnail(ol, ne,Convert.ToInt32(numericUpDownHeight.Value),Convert.ToInt32(numericUpDownWidth.Value));
                }
            }
        }
        public void ShowThumbnail(string oldfile, string newfile, int h, int w)
        {
            lock (lockObj)
            {            System.Drawing.Image img = System.Drawing.Image.FromFile(oldfile);
            System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);            int oldh = img.Height;
            int oldw = img.Width;            int newh, neww;            double h1 = oldh * 1.0 / h;
            double w1 = oldw * 1.0 / w;            double f = (h1 > w1) ? h1 : w1;            if (f < 1.0)
            {
                newh = oldh;
                neww = oldw;
            }
            else
            {
                newh = (int)(oldh / f);
                neww = (int)(oldw / f);
            }            System.Drawing.Image myThumbnail = img.GetThumbnailImage(neww, newh, myCallback, IntPtr.Zero);
            string exFileName = oldfile.Substring(oldfile.LastIndexOf('.')+1).ToLower();
            switch (exFileName)
            {
                case "jpg":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
                case "bmp":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Bmp);
                    break;
                case "jpeg":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
                case "gif":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Gif);
                    break;
                case "png":
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Png);
                    break;
                default:
                    myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                    break;
            }
            
            img.Dispose();
            myThumbnail.Dispose();
           }
        }
        private static bool ThumbnailCallback()
        {
            return false;
        }           #endregion
    }
}

Answer 2

System.Drawing.Image img = System.Drawing.Image.FromFile(oldfile);
这句常会报内存不足的错误，特别是图片本身不能被正确识别，或是文件已经损坏，以及5M以上的超高清的图片，
我常用Backgroundworker来处理这些事情

Answer 3

  img.Dispose();
加一句
img=null; 感觉有效一些

Answer 4

还是报错呢？
我用的是vista的示例图片  应该不会有问题吧 而且我只拷贝了一张

Answer 5

我用其它图片没问题，用vista的示例图片就有问题。很奇怪。

Answer 6

你把vista示例图片的属性惹得祸，你点击图片右键选择属性-详细信息-删除属性和个人信息，然后会生成一个图片的副本，你把那个副本拷过去就没问题。

Answer 7

我猜测是vista在jpg图片中添加了额外的信息，如分级（就是在vista上看到的星星），导致.net framework 2.0的System.Drawing.Image.FromFile认为图片格式有问题，从而出现上边的错。我想用.net framework 3.0的类应该没问。 不过这都是我乱猜的，等待高手出现啦。

Answer 8

嘿嘿 找到解决方法了！
先用文件流处理一下 然后再使用就ok了！
/// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="oldfile">原文件完整路径</param>
        /// <param name="newfile">目标文件完整路径</param>
        /// <param name="h">缩放后的最大高度</param>
        /// <param name="w">缩放后的最大宽度</param>
        /// <returns></returns>
        public bool ShowThumbnail(string oldfile, string newfile, int h, int w)
        {
            lock (lockObj)
            {
                FileStream fss = new FileStream(oldfile, FileMode.Open);
                System.Drawing.Image img = System.Drawing.Image.FromStream(fss);
                System.Drawing.Image.GetThumbnailImageAbort myCallback = new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);                #region 计算高度，宽度
                int oldh = img.Height;
                int oldw = img.Width;                int newh, neww;                double h1 = oldh * 1.0 / h;
                double w1 = oldw * 1.0 / w;                double f = (h1 > w1) ? h1 : w1;                if (f < 1.0)
                {
                    newh = oldh;
                    neww = oldw;
                }
                else
                {
                    newh = (int)(oldh / f);
                    neww = (int)(oldw / f);
                }
                #endregion
                System.Drawing.Image myThumbnail = img.GetThumbnailImage(neww, newh, myCallback, IntPtr.Zero);
                string exFileName = oldfile.Substring(oldfile.LastIndexOf('.') + 1).ToLower();
                switch (exFileName)
                {
                    case "jpg":
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                    case "bmp":
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Bmp);
                        break;
                    case "jpeg":
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                    case "gif":
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Gif);
                        break;
                    case "png":
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Png);
                        break;
                    default:
                        myThumbnail.Save(newfile, System.Drawing.Imaging.ImageFormat.Jpeg);
                        break;
                }
                fss.Close();
                fss.Dispose();
                img.Dispose();
                myThumbnail.Dispose();
                return true;
            }
        }
        private static bool ThumbnailCallback()
        {
            return false;
        }

Answer 9

按你的试了下，好像还是有问题，报错 System.IO.IOException文件"D:\pic\Creek.jpg"正在由另一进程使用，因此该进程无法访问该文件。