Has anyone found a workaround the IMemoryBlobStream.LoadFromFile() error

Question

As far as I am aware, you will get an error if you try to load large file sizes using the function IMemoryBlobStream.LoadFromFile().

Has anyone found some workaround code to load a file into a IMemoryBlobStream?

What I am trying to do is just insert a PDF document file into a BLOB in an Oracle database, but I am not, and do not want to use Oracle API's. I am just using ArcOjects for this one.

My code looks like:

public void LoadReport(string fileName)
{
    try
    {
        if (File.Exists(fileName))
        {
            IMemoryBlobStream2 memoryBlobStream = new MemoryBlobStreamClass();
            memoryBlobStream.LoadFromFile(fileName);

            report = memoryBlobStream;
        }
    }
    catch (Exception ex) {
                throw ex;
    }
}

UPDATE

This is the code I have put to finally get the file in the database, now just need to check reading out the file from the BLOB - hopefully it should work.

fs = new System.IO.FileStream(fileName, FileMode.Open, FileAccess.Read);

byte[] bytes = new byte[fs.Length];

int chunkSize = 2 << 17;

int pos = 0;

for (pos = 0; pos < (fs.Length - chunkSize); pos += chunkSize)
{
    fs.Read(bytes, pos, chunkSize);
}
long modResult = (fs.Length % chunkSize);
fs.Read(bytes, pos,Convert.ToInt32(modResult));

IMemoryBlobStream2 memoryBlobStream = new MemoryBlobStreamClass();
memoryBlobStream.ImportFromMemory(ref bytes[0], (uint)bytes.Length);

fs.Close();

Answer 1

First, load the file into a regular .NET Stream (e.g. a FileStream), then convert it to IMemoryBlobStream as follows:

byte[] bytes = new byte[stream.Length]; // stream is a .NET Stream instance
stream.Read(bytes, 0, bytes.Length);

IMemoryBlobStream memoryBlobStream = new MemoryBlobStreamClass();
memoryBlobStream.ImportFromMemory(ref bytes[0], (uint)bytes.Length);

In your specific scenario you can take a handy shortcut of reading the bytes in a simpler way, by calling File.ReadAllBytes(). It opens, reads and closes a FileStream behind the scenes for you.

Any other instance of a .NET Stream will do the trick, of course.

In any case, this approach is more memory-intensive than IMemoryBlobStream.LoadFromFile() as the data will need to reside in the memory twice before the GC collects the bytes reference.