文件操作问题,The process cannot access the file "E:\1.jpg" because it is being used by anther process

Question

FileStream fs = new (3个参数)我估计是后两个参数的问题

Answer 1

1.drag图片时： 
 private void panel1_DragDrop(object sender, DragEventArgs e)
        {
            try
            {
                new FileIOPermission(PermissionState.Unrestricted).Assert();
                //   StringBuilder fileTable = new StringBuilder();
                foreach (string fileListItem in (e.Data.GetData(DataFormats.FileDrop) as string[]))
                {
                    Bitmap bm = new Bitmap(fileListItem);
                    //get image name
                    int pos = fileListItem.LastIndexOf(@"\") + 1;
                    string name = fileListItem.Substring(pos); ;
                    str = str + 1;
                    Drag darg = new Drag(bm, name, str-2, ds);
                    darg.Left = x * 175 + 15 * (x + 1) + panel1.AutoScrollPosition.X;
                    darg.Top = y * 150 + 10 * (y + 1) + panel1.AutoScrollPosition.Y;
                    darg.Width = 175;
                    darg.Height = 150;
                    //imgList[x] = fileListItem;
                    
                    dr = ds.Tables[0].NewRow();
                    dr[0] = x;
                    dr[1] = fileListItem;
                    ds.Tables[0].Rows.Add(dr);
                 
                    this.panel1.Controls.Add(darg);                    x += 1;
                    if (x % 3 == 0)
                    {
                        x = 0;
                        y += 1;                    }                }              
                CodeAccessPermission.RevertAssert();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }2。上传图片时
   private void CopyWithProgress(string[] filenames)
        {
            
         
            // Display the ProgressBar control.
            this.progressBar1.Visible = true;
            // Set Minimum to 1 to represent the first file being copied.
            progressBar1.Minimum = 1;
            // Set Maximum to the total number of files to copy.
            progressBar1.Maximum = filenames.Length;
          //  MessageBox.Show(filenames.Length.ToString());
            // Set the initial value of the ProgressBar.
            progressBar1.Value = 1;
            // Set the Step property to a value of 1 to represent each file being copied.
            progressBar1.Step = 1;
           
            for (int x = 0; x < filenames.Length; x++)
            {
               
                int pos = filenames[x].LastIndexOf(@"\") + 1;
                
                string filename = filenames[x].Substring(pos); 
                this.labFilename.Text = filenames[x];
               //这里出现了问题,
                FileStream fs = File.Create(filename[x].ToString());
//这里出现了问题
                byte[] info=new byte[fs.Length];
                fs.Close();
                if (uploadService.UploadFiles(info, @"img\" + filename))
                {
                   // MessageBox.Show("Upload Images");
                }
                else
                {
                    MessageBox.Show("No Upload Images");                }
              
             
                progressBar1.PerformStep();
                Bitmap bm = new Bitmap(filenames[x]);
                this.pictureBox1.Image = bm;
            }        }

Answer 2

请问 new FileIOPermission(PermissionState.Unrestricted).Assert();这行是什么作用？而这里未指明要访问哪个路径啊？
我写了个类，将文件上传到服务器上，在本机上可以正常，但服务器上则不行，提示错误：
Request for the permission of type 'System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.网上找了关于安全的资料，没找到相关的说法，有没有高手这方面的资料？

Answer 3

 Bitmap   bm   =   new   Bitmap(fileListItem); 
这一句从文件创建位图实际已经独占了了文件。
可以改成这样。
using (Bitmap bit = new Bitmap(fileListItem))
{ this.panel1.BackgroundImage = bit.GetThumbnailImage(panel1.Width, panel1.Height, null, IntPtr.Zero);
}
另外你的文件上传代码中
FileStream   fs   =   File.Create(filename[x].ToString()); 
//这里出现了问题 
                                byte[]   info=new   byte[fs.Length]; 
                             fs.Close(); 
这几句似乎逻辑就有问题。文件已经存在了，为什么又要新建文件而不是打开读取，那文件长度字节不是成为0了吗？