Extracting binary file from sql database image field to disk

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G

Guest

I am trying to extract a zip file in a database image field to disk. For some
reason, the zip file is getting corrupted / truncated. I have code in ASP
which extracts the zip file no problem, so i know it is not corrupted in the
table. Any help would be appreciated.

FileStream fs = new FileStream(sFilePath + "TestFile.zip",
FileMode.CreateNew);
BinaryWriter bw = new BinaryWriter(fs);
byte[] buffer =
Encoding.ASCII.GetBytes(DataReader[sField].ToString());
bw.Write(buffer);
bw.Close();
fs.Close();
 
Scott said:
I am trying to extract a zip file in a database image field to disk. For some
reason, the zip file is getting corrupted / truncated. I have code in ASP
which extracts the zip file no problem, so i know it is not corrupted in the
table. Any help would be appreciated.

FileStream fs = new FileStream(sFilePath + "TestFile.zip",
FileMode.CreateNew);
BinaryWriter bw = new BinaryWriter(fs);
byte[] buffer =
Encoding.ASCII.GetBytes(DataReader[sField].ToString());
bw.Write(buffer);
bw.Close();
fs.Close();
Click to expand...

Don't convert the binary data to a string - that's a recipe for a
disaster.

If you look at DataReader[sField].GetType(), what does it say?
 
Matt F said:
I use the binaryformatter class for this type of thing --- MSDN example for
the binaryformatter class has a pretty good example.
Click to expand...

It's a zip file - natural binary data to start with. Serializing it
would add an extra layer for no good reason, *and* make it
hard/impossible to use from other platforms.
 
Jon Skeet said:
Scott said:
I am trying to extract a zip file in a database image field to disk. For some
reason, the zip file is getting corrupted / truncated. I have code in ASP
which extracts the zip file no problem, so i know it is not corrupted in the
table. Any help would be appreciated.

FileStream fs = new FileStream(sFilePath + "TestFile.zip",
FileMode.CreateNew);
BinaryWriter bw = new BinaryWriter(fs);
byte[] buffer =
Encoding.ASCII.GetBytes(DataReader[sField].ToString());
bw.Write(buffer);
bw.Close();
fs.Close();
Click to expand...

Don't convert the binary data to a string - that's a recipe for a
disaster.

If you look at DataReader[sField].GetType(), what does it say?
Click to expand...
The DataReader[sField].GetType() comes back as System.String
 
Scott said:
If you look at DataReader[sField].GetType(), what does it say?
Click to expand...
Click to expand...
The DataReader[sField].GetType() comes back as System.String
Click to expand...

Okay, that's a bad start. What's the data type in the database, and how
have you stored the zip file in there in the first place? Storing a
binary block of data (such as a zip file) in a text field is a really
bad move...
 
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