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Problem with stream in Aspose.Words

Aspose.Words Product Family
#1

I'm having trouble opening a document with a stream using Apose.Words...

I'm creating a document and saving its contents to a column in the database. I would then like to retreive the DB column and use its content to open the document at a later date...

I'm successfully using the following code to save the document to the DB::

Document doc = new Document();

DocumentBuilder builder = new DocumentBuilder(doc);

builder.Writeln("Test");

MemoryStream ms = new MemoryStream();

doc.Save(ms, SaveFormat.FormatDocument);

string dbColumn= System.Text.Encoding.ASCII.GetString(ms.ToArray());

I'm using the following code to open the document from a stream using the column from the database:

byte[] buffer = System.Text.Encoding.ASCII.GetBytes(dbColumn);

MemoryStream ms2 = new MemoryStream(buffer);

Document doc2 = new Document(ms2, string.Empty, LoadFormat.FormatDocument, string.Empty);

Unfortunately, the call to Document() results in the following error: "This is not a structured storage file."

Any idea why this is happening? Any help would be greatly appreciated...

#2

It seems that you need to move the stream pointer to the beginning of the stream befor loading the document from it:

MemoryStream ms2 = new MemoryStream(buffer);

ms2.Seek(0, SeekOrigin.Begin);

Document doc2 = new Document(ms2);

#3

Adding the call:

ms2.Seek(0, SeekOrigin.Begin)

prior to opening the document results in the same error message. In my previous testing, I had made this call but removed it since the value of m2.Position was already 0.

If I attempt to call Document doc2 = new Document(ms2) as you suggested, I get the following error message: "Unknown file format."

I'm beginning to wonder if the following code for creating the memory stream from a string is at fault:

byte[] buffer = System.Text.Encoding.ASCII.GetBytes(rtf);

MemoryStream ms2 = new MemoryStream(buffer);

If I open the document with the original stream, as such:

Document doc2 = new Document(ms, string.Empty, LoadFormat.FormatDocument, string.Empty);

the call succeeds.

This is very strange...

#4

ASCII encoding won't work in this case because it truncates the most significant bit of the byte. Of all well-known encodings only Unicode encoding will work here but it will effectively double the size of the stored string. The other option is to convert memory stream to/from string using the following procedures:

// convert memory stream to string

StringBuilder sb = new StringBuilder((int)ms.Length);

foreach(byte b in ms.ToArray())

{

sb.Append((char)b);

}

string dbColumn = sb.ToString();

// convert string to memory stream

byte[] buffer = new byte[dbColumn.Length];

int i = 0;

foreach(char ch in dbColumn)

{

buffer[i++] = (byte)ch;

}

MemoryStream ms2 = new MemoryStream(buffer);

#5

Your procedures to convert memory stream to/from string proved useful.

My problem was compounded by the fact that the truncation of the most significant bits also happened when saving to a database column defined as a string/text type. After changing my DB column to an image/byte[] type, everything worked like a charm...

Thank you very much for your help…