C# 读取文件后删除提示被占用但是我已经释放了资源啊？

Question

DirectoryInfo dir = new DirectoryInfo(@"FingerImage");
try
{
foreach (FileInfo fileInfo in dir.GetFiles("*.bmp"))
{
MessageBox.Show(fileInfo.Name,"INFO");
byte[] nameTemp = Encoding.Default.GetBytes(Path.GetFileName(fileInfo.FullName));
byte[] recvBuf = new byte[32];

                using (FileStream picture = fileInfo.OpenRead())
                {
                    byte[] picsize = new byte[fileInfo.Length + 4096];
                    picture.Read(picsize, 0, picsize.Length - 1);
                    picture.Dispose();
                    picture.Close();
                    GC.ReRegisterForFinalize(picture);
                    GC.ReRegisterForFinalize(fileInfo);

                    string nameStr = "IMAGE<#>" + Encoding.UTF8.GetString(nameTemp).Length + "<#>" + Encoding.UTF8.GetString(nameTemp) + "<#>" + picsize.Length + "<#>|END|";
                    byte[] name = Encoding.UTF8.GetBytes(nameStr);
                    //发送图片名
                    sockClient.Send(name);
                    //接受反馈
                    int iRet = sockClient.Receive(recvBuf);
                    if (iRet == 0)
                    {
                        MessageBox.Show("服务器异常", "提示：");
                        flag = false;
                    }
                    else
                    {
                        if (String.Compare(Encoding.Default.GetString(recvBuf), "YES") == 0)
                        {
                            sockClient.Send(picsize);
                            //发送图片
                            iRet = sockClient.Receive(recvBuf);
                            if (iRet == 0)
                            {
                                MessageBox.Show("服务器异常", "提示：");
                                flag = false;
                            }
                            else
                            {
                                if (String.Compare(Encoding.Default.GetString(recvBuf), "YES") == 0)
                                {
                                    MessageBox.Show("上传成功", "提示：");
                                }
                                else
                                {
                                    lab_msg.Text = Encoding.Default.GetString(recvBuf);
                                    flag = false;
                                }
                            }
                        }
                        else
                        {
                            MessageBox.Show(Encoding.Default.GetString(recvBuf), "提示：");
                            flag = false;
                        }
                    }
                }
                //if (File.Exists(fileInfo.FullName))
                //{
                //    File.Delete(fileInfo.FullName);
                //}提示被占用
                //FileStream picture = new FileStream(fileInfo.FullName, FileMode.Open, FileAccess.Read);

            }
            Directory.Delete(dir.FullName,true);//可以删除，但是最后一张提示被占用，无法删除
        }
        catch (Exception e)
        {
            MessageBox.Show(this, e.Message, "客户端异常");
        }

Answer 1

 string[] fileNames = Directory.GetFiles(@"FingerImage","*.bmp");
            try
            {
                foreach (string item in fileNames)
                {
                    MessageBox.Show(item, "INFO");
                    byte[] recvBuf = new byte[32];
                    FileStream picture = new FileStream(item, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
                    int index = item.LastIndexOf(@"\");
                    string filename = item.Substring(index + 1, item.Length - index - 1);
                    MessageBox.Show(filename, "INFO");
                    byte[] picsize = new byte[picture.Length + 4096];
                    picture.Read(picsize, 0, picsize.Length - 1);
                    picture.Dispose();
                    picture.Close();
                    GC.ReRegisterForFinalize(picture);

                    string nameStr = "IMAGE<#>" + filename.Length + "<#>" + filename + "<#>" + picsize.Length + "<#>|END|";
                    byte[] name = Encoding.UTF8.GetBytes(nameStr);
                    //发送图片名
                    sockClient.Send(name);
                    //接受反馈
                    int iRet = sockClient.Receive(recvBuf);
                    if (iRet == 0)
                    {
                        MessageBox.Show("服务器异常", "提示：");
                        flag = false;
                    }
                    else
                    {
                        if (String.Compare(Encoding.Default.GetString(recvBuf), "YES") == 0)
                        {
                            sockClient.Send(picsize);
                            //发送图片
                            iRet = sockClient.Receive(recvBuf);
                            if (iRet == 0)
                            {
                                MessageBox.Show("服务器异常", "提示：");
                                flag = false;
                            }
                            else
                            {
                                if (String.Compare(Encoding.Default.GetString(recvBuf), "YES") == 0)
                                {
                                    MessageBox.Show("上传成功", "提示：");
                                }
                                else
                                {
                                    lab_msg.Text = Encoding.Default.GetString(recvBuf);
                                    flag = false;
                                }
                            }
                        }
                        else
                        {
                            MessageBox.Show(Encoding.Default.GetString(recvBuf), "提示：");
                            flag = false;
                        }
                    }
                    File.Delete(item);
                }
            }
            catch (Exception e)
            {
                MessageBox.Show(this, e.Message, "客户端异常");
            }

我尝试改了代码，但是还是不行，删除单个文件时报异常被占用，删除整个目录最后一个无法删除