使用C＃从BLOB Oracle下载文件

Question

i have created simple project in c# to save file data into Oracle Database using BLOB data type and it worked. i used devexpress gridcontrol to show the data. This is the sample data that i have created.

in the btnDownload will download data from blob oracle that i selected row. here is my code:

var rowHandle = gridView1.FocusedRowHandle;
var obj = gridView1.GetRowCellValue(rowHandle, "FILENAME");

if(koneksidb.con.State == ConnectionState.Open)
{
    koneksidb.con.Close();
}
koneksidb.con.Open();
OracleCommand cmd = new OracleCommand();
OracleDataReader dr;
cmd.CommandText = @"SELECT * FROM LATIHANFILEMANAGER WHERE FILENAME='"+ obj +"'";
cmd.Connection = koneksidb.con;
dr = cmd.ExecuteReader();
while(dr.Read())
{
    UInt32 FileSize = Convert.ToUInt32(dr.GetInt32(dr.GetOrdinal("FILESIZE"))); //get file size from table LATIHANFILEMANAGER
    rawData = new byte[FileSize];
    var nilai = dr.GetBytes(dr.GetOrdinal("FILEDATA"), 0, rawData, 0, (int)FileSize); //this file that i wanna download
    FileStream fls = new FileStream(@"D:\newfile.png", FileMode.OpenOrCreate, FileAccess.Write);
    fls.Write(rawData, 0, (int)FileSize);
    fls.Close();
}
dr.Close();

when i run this project and download the image, i got a file and file size but it cannot be opened.

here is the file that i captured:

this tutorial i got from this link: https://docs.oracle.com/cd/E17952_01/connector-net-en/connector-net-programming-blob-reading.html

any suggest?

Answer 1

first, you show your Image(BLOB) from database to PictureBox, than use SaveFileDialog. for more information visit How to use saveFileDialog for saving images in C#?