我正在开发一个C＃工具，用于从未格式化的SD卡读取8 gb十六进制数据。
它能够这样做，但它会随机抛出File Not Found Exception。例如，它会读取一两千兆字节，然后抛出它。其他时候它会连续几次读取所有8 gbs，然后抛出异常。换句话说，它似乎完全随机弹出。
我不知道是什么原因造成的。
编辑：我使用反馈来调整一些事情。下面粘贴的是更新的代码。它仍会随机抛出filenotfoundexception，但它现在总是在尝试读取gig 8的mb 432时抛出一个参数异常（如果它在没有随机抛出filenotfound的情况下得到那么远）。
错误抱怨文件句柄不支持同步操作。
class Program
{
[DllImport("kernel32.dll", SetLastError = true, CharSet = CharSet.Unicode)]
static extern SafeFileHandle CreateFile(string lpFileName, uint dwDesiredAccess,
uint dwShareMode, IntPtr lpSecurityAttributes, uint dwCreationDisposition,
uint dwFlagsAndAttributes, IntPtr hTemplateFile);
static void Main(string[] args)
{
string testOutputDirectory = @"C:\\Users\\aiovanna\\Desktop\\out1.txt"; //Specifies where to write the results of the read.
try
{
SafeFileHandle fileHandle = CreateFile("\\\\.\\E:", 0x80000000, 0, IntPtr.Zero, 3, 0, IntPtr.Zero);
FileStream readStream = new FileStream(fileHandle, FileAccess.Read); //The stream to be read. Is converted to binary.
BufferedStream bufStream = new BufferedStream(readStream, 1048576);
FileStream writeStream = File.OpenWrite(testOutputDirectory); //Writing stream opened at the specified directory of output.
//BinaryReader reader = new BinaryReader(readStream); //Changes the read stream to binary. Has more powerful methods.
long gigsRead; //Loop counter that specifies the number of gigabytes read thus far.
long megsRead; //Loop counter that specifies the number of megabytes read thus far within the current gigabyte.
Stopwatch totalStopwatch = new Stopwatch(); //Stopwatch to time the total execution of the card read.
Stopwatch megStopwatch = new Stopwatch(); //Stopwatch to time the execution of reading the current megabyte.
Stopwatch gigStopwatch = new Stopwatch(); //Stopwatch to time the executation of reading the current gigabyte.
totalStopwatch.Start(); //Start timing the program.
int bytesRead;
for (gigsRead = 0; gigsRead < 8; gigsRead++) //Gigabyte loop
{
gigStopwatch.Start(); //Start timer for current gigabyte.
for (megsRead = 0; megsRead < 1024; megsRead++) //Megabyte loop
{
megStopwatch.Start(); //Start timer for current megabyte.
try
{
byte[] buffer = new byte[1048576]; //Buffer to be read into from card
long test = gigsRead * 1073741824 + megsRead * 1048576;
bufStream.Position = test;
bytesRead = bufStream.Read(buffer, 0, 1048576); //Read from SD card to buffer
if (bytesRead < 1048576)
{
Console.WriteLine("Didn't read whole chunk!");
}
writeStream.Write(buffer, 0, 1048576); //Write from buffer to output text file.
megStopwatch.Stop(); //Stop timer for current megabyte.
Console.WriteLine("Finished mb {0} of gig {1} in {2}", megsRead + 1, gigsRead + 1, megStopwatch.Elapsed);
megStopwatch.Reset(); //Reset for next megabyte.
}
catch (System.IO.FileNotFoundException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace: {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
System.Console.WriteLine(ex.ToString());
writeStream.Close(); //Close writing stream.
//reader.Close(); //Close the binary reader stream.
bufStream.Close();
fileHandle.Close(); //Close the SD card file.
readStream.Close(); //Close the filestream reader.
System.Console.WriteLine("You will need to turn off your computer, take out the card, turn the computer back on, put the SD card back in, and re-run the program.");
System.Console.WriteLine("Press any key to terminate.");
System.Console.ReadKey();
System.Environment.Exit(1);
}
catch (System.ArgumentException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Param Name: {0}", ex.ParamName);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace: {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
System.Console.WriteLine(ex.ToString());
writeStream.Close(); //Close writing stream.
//reader.Close(); //Close the binary reader stream.
fileHandle.Close(); //Close the SD card file.
readStream.Close(); //Close the filestream reader.
System.Console.WriteLine("You will need to turn off your computer, take out the card, turn the computer back on, put the SD card back in, and re-run the program.");
System.Console.WriteLine("Press any key to terminate.");
System.Console.ReadKey();
System.Environment.Exit(1);
}
}
gigStopwatch.Stop(); //Stop timer for current gigabyte.
Console.WriteLine("Finished gig {0} in {1}", gigsRead + 1, gigStopwatch.Elapsed);
gigStopwatch.Reset(); //Reset for next gigabyte.
}
totalStopwatch.Stop(); //Stop total execution timer.
Console.WriteLine(totalStopwatch.Elapsed); //Print total execution timer.
writeStream.Close(); //Close writing stream.
//reader.Close(); //Close the binary reader stream.
writeStream.Close(); //Close writing stream.
fileHandle.Close(); //Close the SD card file.
readStream.Close(); //Close the filestream reader.
bufStream.Close();
}
catch (System.IO.IsolatedStorage.IsolatedStorageException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Isolated Storage Exception");
System.Console.WriteLine("Data: {0}", ex.Data);
System.Console.WriteLine("Help Link: {0}", ex.HelpLink);
System.Console.WriteLine("Inner Exception: {0}", ex.InnerException);
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
Console.ReadKey();
}
catch (System.ArgumentException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Argument Exception");
System.Console.WriteLine("Data: {0}", ex.Data);
System.Console.WriteLine("Help Link: {0}", ex.HelpLink);
System.Console.WriteLine("Inner Exception: {0}", ex.InnerException);
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Param Name: {0}", ex.ParamName);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
Console.ReadKey();
}
catch (System.IO.DirectoryNotFoundException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Directory Not Found Exception");
System.Console.WriteLine("Data: {0}", ex.Data);
System.Console.WriteLine("Help Link: {0}", ex.HelpLink);
System.Console.WriteLine("Inner Exception: {0}", ex.InnerException);
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
System.Console.ReadKey();
}
catch (System.ObjectDisposedException ex)
{
System.Console.WriteLine("The error was: {0}", Marshal.GetLastWin32Error());
System.Console.WriteLine("Object Disposed Exception");
System.Console.WriteLine("Data: {0}", ex.Data);
System.Console.WriteLine("Help Link: {0}", ex.HelpLink);
System.Console.WriteLine("Inner Exception: {0}", ex.InnerException);
System.Console.WriteLine("Message: {0}", ex.Message);
System.Console.WriteLine("Object Name {0}", ex.ObjectName);
System.Console.WriteLine("Source: {0}", ex.Source);
System.Console.WriteLine("Stack Trace {0}", ex.StackTrace);
System.Console.WriteLine("Target Site: {0}", ex.TargetSite);
Console.ReadKey();
}
}
}
下面我重新编写了filenotfoundexception显示的错误：
消息：无法找到指定的文件。 资料来源：mscorlib 堆栈跟踪：在System.IO .__ Error.WinIOError（int32 errorcode，String maybeFullPath） 在System.IO.FileStream.ReadCore（Byte []缓冲区，int32偏移量，int32计数） 在System.IO.FileStream.Read（Byte []数组，Int32偏移量，Int32计数） 在System.IO.BinaryReader.Read（Byte []缓冲区，Int32索引，Int32计数） 在RawSDAccessTest.Program.Main（String {} args）在C：\ Users \ etc ...在第67行 目标站点：无效WinIOError（Int32，System.String） System.IO.FileNotFoundException：无法找到指定的文件。 第67行是： reader.Read（buffer，0,1048576）;
我觉得这里真的很奇怪，程序完全没问题，第65行也使用了读者对象。不知何故，在执行第65行和第67行之间，它决定该文件不再存在。我把等待放在两者之间，看看是否会解决它。它没有。
关于什么可能导致它随机抛出此异常或如何解决它的任何想法？
编辑：进程监视器显示以下内容
8：40：26.1077157 AM SDCardReadAttempt3.vshost.exe 2432 ReadFile E：SUCCESS Offset：3,228,565,504，Length：1,048,576，I / O标志：非缓存，优先级：正常
8：40：26.1745974 AM SDCardReadAttempt3.vshost.exe 2432 ReadFile E：NO SUCH DEVICE Offset：3,229,614,080，Length：131,072，I / O标志：非缓存，优先级：正常
因此，在读取之间，设备不再存在。我将文件创建和删除移动到内部循环，以便每次尝试从中读取时都会创建文件。问题依然存在。闻起来像硬件给我。
编辑2：现在它偶尔会抛出一个异步读取异常。
9：16：16.1129926 AM SDCardReadAttempt3.vshost.exe 3752 ReadFile E：INVALID PARAMETER Offset：7,969,177,600，Length：1,048,576，I / O标志：非缓存，优先级：正常
我不知道.net如何深入工作。当文件未打开以供多个线程读取时，它可能会将其变为线程化进程。我会把等待放回去看看是否能消除这个错误，所以我可以回到原来的错误。
答案 0 :(得分：1)
我从扫描仪上读到了类似的问题。我最终不得不抓住异常，等待一段时间（250毫秒适合我的目的），然后尝试重新读取相同的数据。我定义了一个阈值（6对我来说效果很好），此时我放弃并向用户提出错误。
在大多数情况下，这似乎给硬件足够的时间来追赶。
另外，请尝试阅读给您带来麻烦的区块。如果您在读取特定块时始终遇到错误，那么您显然遇到了硬件问题。
答案 1 :(得分：0)
这可能是一个很长的镜头，但你尝试过ReadAsync方法吗？
http://msdn.microsoft.com/en-us/library/hh137813.aspx