由于某些原因，我想将一个GUID作为ID写入一个文件进行保存，并在打开文件之前删除该ID。
static void Main(string[] args)
{
string id = "b669fd8c904d48e0945c16cac1dc5ed9";
byte[] idbyte = UnicodeEncoding.Default.GetBytes(id);
FileStream input = new FileStream(@"C:\test.xlsx", FileMode.Open, FileAccess.Read);
FileStream output = new FileStream(@"C:\test1.xlsx", FileMode.OpenOrCreate, FileAccess.Write);
CopyStream(input, output);
// add id with byte[] at the end of the file
output.Write(idbyte, 0, idbyte.Length);
output.Close();
input.Close();
FileStream input1 = new FileStream(@"C:\test1.xlsx", FileMode.Open, FileAccess.Read);
FileStream output1 = new FileStream(@"C:\test2.xlsx", FileMode.OpenOrCreate, FileAccess.Write);
int SizeOfBuffer = 1024 * 16;
try
{
byte[] buffer = new byte[SizeOfBuffer];
byte[] bufferLast = new byte[SizeOfBuffer];
int read;
int Nextread;
while ((read = input1.Read(buffer, 0, buffer.Length)) > 0)
{
if ((Nextread = input1.Read(bufferLast, 0, buffer.Length)) > 0)
{
output1.Write(buffer, 0, read);
output1.Write(bufferLast, 0, Nextread);
}
else // delete id with byte[]
{
byte[] buffer2 = new byte[SizeOfBuffer];
for (int i = 0; i < read - idbyte.Length; i++)
{
buffer2[i] = buffer[i];
}
output1.Write(buffer2, 0, buffer2.Length);
break;
}
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
output1.Close();
input1.Close();
Console.ReadLine();
}
private static void CopyStream(Stream input, Stream output)
{
int SizeOfBuffer = 1024 * 16;
try
{
byte[] buffer = new byte[SizeOfBuffer];
int read;
while ((read = input.Read(buffer, 0, buffer.Length)) > 0)
{
output.Write(buffer, 0, read);
}
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
但是当我打开C：\ test2.xlsx时，excel显示错误：“Excel在'test2.xlsx'中找到了不可读的内容”！
如何解决这个问题？
答案 0 :(得分：0)
以下适用于我。正如您所看到的，我做了一些重组，因此我可以更轻松地告诉我正在做什么并简化测试。如果您有任何问题，请告诉我。
class Program
{
private const int SIZE_OF_BUFFER = 1024 * 16;
private const string FILE_PATH_ORIGINAL = @"C:\test.xlsx",
FILE_PATH_WithId = @"C:\test1.xlsx",
FILE_PATH_IdRemoved = @"C:\test2.xlsx";
private static readonly byte[] idbyte = UnicodeEncoding.Default.GetBytes("b669fd8c904d48e0945c16cac1dc5ed9");
static void Main(string[] args)
{
AddGuidToFile(FILE_PATH_ORIGINAL, FILE_PATH_WithId);
RemoveGuidToFile(FILE_PATH_WithId, FILE_PATH_IdRemoved);
CompairFiles(FILE_PATH_ORIGINAL, FILE_PATH_IdRemoved);
Console.ReadLine();
}
private static void AddGuidToFile(string sourceFilePath, string destinationFilePath)
{
byte[] buffer = new byte[SIZE_OF_BUFFER];
FileStream input = new FileStream(sourceFilePath, FileMode.Open, FileAccess.Read),
output = new FileStream(destinationFilePath, FileMode.OpenOrCreate, FileAccess.Write);
int read;
try
{
while ((read = input.Read(buffer, 0, buffer.Length)) > 0) //Copy source file to destination file.
{
output.Write(buffer, 0, read);
}
output.Write(idbyte, 0, idbyte.Length); //Add guid to the end of the destination file.
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
finally
{
//Close files
input.Close();
output.Close();
}
}
private static void RemoveGuidToFile(string sourceFilePath, string destinationFilePath)
{
byte[] currentBuffer = new byte[SIZE_OF_BUFFER],
nextBuffer = new byte[SIZE_OF_BUFFER],
tempBuffer;
FileStream input = new FileStream(sourceFilePath, FileMode.Open, FileAccess.Read),
output = new FileStream(destinationFilePath, FileMode.OpenOrCreate, FileAccess.Write);
int currentRead,
nextRead = 0; //Initialize to 0 incase file's lenght is less then SizeOfBuffer.
try
{
currentRead = input.Read(currentBuffer, 0, currentBuffer.Length); //Get first chunk.
if (currentRead == currentBuffer.Length) //If first chunck is a full buffer then loop until it is not.
{
nextRead = input.Read(nextBuffer, 0, nextBuffer.Length);
while (nextRead > idbyte.Length)
{
output.Write(currentBuffer, 0, currentRead); //Since nextBuffer is large enough to contain the ID, write the current buffer out.
//Swap buffers.
tempBuffer = currentBuffer;
currentBuffer = nextBuffer;
nextBuffer = tempBuffer;
//Update counts and fill next buffer.
currentRead = nextRead;
nextRead = input.Read(nextBuffer, 0, nextBuffer.Length);
}
}
currentRead += nextRead - idbyte.Length; //Update currentRead to be the number of bytes in the buffer which are not part of the ID.
output.Write(currentBuffer, 0, currentRead);
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
finally
{
//Close files
input.Close();
output.Close();
}
}
private static void CompairFiles(string originalFilePath, string idRemovedFilePath)
{
byte[] originalBuffer = new byte[SIZE_OF_BUFFER],
idRemovedBuffer = new byte[SIZE_OF_BUFFER];
FileStream original = new FileStream(originalFilePath, FileMode.Open, FileAccess.Read),
idRemoved = new FileStream(idRemovedFilePath, FileMode.Open, FileAccess.Read);
int originalRead,
idRemovedRead;
try
{
do
{
originalRead = original.Read(originalBuffer, 0, originalBuffer.Length);
idRemovedRead = idRemoved.Read(idRemovedBuffer, 0, idRemovedBuffer.Length);
if (originalRead != idRemovedRead) { throw new Exception("Error: file sizes do not match. originalRead = " + originalRead + ", idRemovedRead = " + idRemovedRead + ", SIZE_OF_BUFFER = " + SIZE_OF_BUFFER); }
for (int i = 0; i < originalRead; i++)
{
if (originalBuffer[i] != idRemovedBuffer[i]) { throw new Exception("Error: file contents do not match. i = " + i + ",inputBuffer[i] = " + originalBuffer[i] + ", idRemovedBuffer[i] = " + idRemovedBuffer[i]); }
}
}
while (originalRead == idRemovedRead && originalRead > 0);
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
finally
{
//Close files
original.Close();
idRemoved.Close();
}
}
}
答案 1 :(得分：0)
扩展名为xlsx的Excel文件（请注意末尾的“x”）实际上是zip个文件，其中包含xml个文档。如果将数据添加到文件末尾，则会使zip无效，因此Excel无法打开它。
看起来您的功能可能无法正确删除添加的文本。您可以尝试在十六进制比较程序中打开原始文件和新文件，以查看它们的不同之处。此外，您可以将文件重命名为“.zip”以查看它是否以zip程序打开。