lecture d'un champ BLOB

Question

Bonjour,

J'aurai aimé recuperer en C# le contenu d'un champ BLOB dans une base de donnée advantage.

Le champ BLOB est une image au format BMP dans un de mes exemples et au format XML dans un autre.

J'ai essayé ce code:

           FileStream fs;                          // Writes the BLOB to a file (*.bmp).
BinaryWriter bw;                        // Streams the BLOB to the FileStream object.
int bufferSize = 100;                   // Size of the BLOB buffer.
byte[] outbyte = new byte[bufferSize];  // The BLOB byte[] buffer to be filled by GetBytes.
long retval;                            // The bytes returned from GetBytes.
long startIndex = 0;                    // The starting position in the BLOB output.
string emp_id = "";                     // The employee id to use in the file name.

// Open the connection and read data into the DataReader.
connection.Open();
AdsDataReader myReader = dataAdapter.SelectCommand.ExecuteReader(CommandBehavior.SequentialAccess);

while (myReader.Read())
{
// Get the employee id, which must occur before getting the employee.
emp_id = myReader.GetInt32(0).ToString();

// Create a file to hold the output.
fs = new FileStream("employee" + emp_id + ".bmp",
FileMode.OpenOrCreate, FileAccess.Write);
bw = new BinaryWriter(fs);

// Reset the starting byte for the new BLOB.
startIndex = 0;

// Read the bytes into outbyte[] and retain the number of bytes returned.
retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);

// Continue reading and writing while there are bytes beyond the size of the buffer.
while (retval == bufferSize)
{
bw.Write(outbyte);
bw.Flush();

// Reposition the start index to the end of the last buffer and fill the buffer.
startIndex += bufferSize;
retval = myReader.GetBytes(1, startIndex, outbyte, 0, bufferSize);
}

// Write the remaining buffer.
bw.Write(outbyte, 0, (int)retval);
bw.Flush();

// Close the output file.
bw.Close();
fs.Close();
}

// Close the reader and the connection.
myReader.Close();
connection.Close();

}//fin du try

Quelqu'un aurai t'il une idée car la fonction ne marche pas !! la connection ce crée et la boucle est bonne mais le "emp_id = myReader.GetInt32(0).ToString();" ne charge rien du tout

:S

cs_FiSH · Answer

http://www.codeproject.com/cs/database/albumviewer.asp

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Lecture d'un champ BLOB

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