如何显示来自Oracle Blob数据的图像 [英] how to display image from oracle blob data

问题描述

Hii，
我试图在.net Windows应用程序中显示来自oracle10g的Blob数据类型的图像.
我正在使用文件流获取图像，但是当我为显示图像设置蒸汽对象时，它显示错误(无法访问关闭的文件).

我的代码如下.

Hii,
i am trying to display image from Blob datatype of oracle10g in .net windows application.
i am using filestream to get the image but the when i set the steam object for display image it show the error (Cannot access a closed file).

My code is below.

OracleConnection con = new OracleConnection("Data Source=localhost;uid=test;pwd=test;");
            con.Open();
            try
            {
                OracleCommand cmd = new OracleCommand("Select Token_no,Photo from party_photo where token_no=8629", con);
                // Writes the BLOB to a file (*.bmp).
                FileStream stream;
                // Streams the BLOB to the FileStream object.
                BinaryWriter writer;

                // Size of the BLOB buffer.
                int bufferSize = 100;
                // The BLOB byte[] buffer to be filled by GetBytes.
                byte[] outByte = new byte[bufferSize];
                // The bytes returned from GetBytes.
                long retval;
                // The starting position in the BLOB output.
                long startIndex = 0;

                // The publisher id to use in the file name.
                string token_no = "";

                OracleDataReader reader = cmd.ExecuteReader(CommandBehavior.SequentialAccess);
                while (reader.Read())
                {
                    //token_no = reader.GetString(0);
                    token_no = Convert.ToString(reader[0]);
                    stream = new FileStream("Photo" + token_no + ".bmp", FileMode.OpenOrCreate, FileAccess.Write);
                    writer = new BinaryWriter(stream);
                    startIndex = 0;
                    retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);
                    while (retval == bufferSize)
                    {
                        writer.Write(outByte);
                        writer.Flush();

                        startIndex += bufferSize;
                        retval = reader.GetBytes(1, startIndex, outByte, 0, bufferSize);

                    }
                    writer.Write(outByte, 0, (int)retval - 1);
                    writer.Flush();

                    //stream.Write(outByte, 0, (int)retval = 1);
                    writer.Close();
                    pictureBox1.Image  = Image.FromStream(stream);
                    stream.Close();
                    
                }
                reader.Close();
                



            }
            catch (Exception error)
            {
                MessageBox.Show(error.Message, "", MessageBoxButtons.OK);
            }
            finally
            {
                con.Close();
            }

请帮助我解决这个问题.


谢谢

Please help me to short out this problem.


Thanks

推荐答案

您在这里

修复链接
无法访问已关闭的文件 [ ObjectDisposedException-无法访问关闭的文件 [ ^ ]
ObjectDisposedException-无法访问关闭的文件[已解决] [ ^ ]
无法访问已关闭的文件– ASP.NET中的FileUpload [ ^ ]

从Oracle读取BLOB或向Oracle写入BLOB
使用C#.NET DataSet和DataReader [ ^ ]
使用C#.Net将图像插入Oracle数据库的Blob字段中/从Blob字段中检索图像 [ ^ ]
Oracle BLOB数据类型和C# [ ^ ]

Here you go

Fix links
Cannot access a closed file[^]
ObjectDisposedException - Cannot Access a Closed File[^]
ObjectDisposedException - Cannot access a closed file[Solved][^]
cannot access a closed file – FileUpload in ASP.NET[^]

Read / Write BLOBs from / to Oracle
using C# .NET DataSet and DataReader[^]
Insert /retrieve an image into/ from a blob field in Oracle database using C#.Net[^]
Oracle BLOB data type and C#[^]

切换到 ODAC [ ^ ]可能一个好主意，因为MS已弃用其oracle ado.net驱动程序.

您还将获得更适合于检索oracle blob类型的功能.

最好的问候
Espen Harlinn

Switching to ODAC[^] is probably a good idea, as MS has deprecated their oracle ado.net driver.

You''ll also get access to functionality that is better suited for retreiving oracle blob types.

Best regards
Espen Harlinn

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