Ole对象在Access中存储为二进制文件，读取的时候需要注意转换出的文件的编码格式

1

OleDbConnection OleConn=newOleDbConnection();2OleConn.ConnectionString=@"Provider=Microsoft.Jet.OleDb.4.0;data source=D:\WorkStation\Dialy_Sol\Dialy\Dialy.mdb";3OleDbCommand OleCmd=newOleDbCommand();4OleCmd.Connection=OleConn;5OleCmd.CommandType=CommandType.Text;6OleCmd.CommandText="SELECT Dialy_Content FROM Dialy_Info WHERE Dialy_Date='2008-5-2'";7if(OleConn.State==ConnectionState.Closed)8

{9OleConn.Open();10}11stringDialyContent="";12byte[] Buff=newbyte[1000];13OleDbDataReader OleReader=OleCmd.ExecuteReader();14while(OleReader.Read())15

{16OleReader.GetBytes(0,0, Buff,0,1000);17DialyContent+=Encoding.Unicode.GetString(Buff);18}< /span>19< span style="color: #000000;">

//DialyContent就是读取出来后的中文

---------------------------下面是读取写入的示例---------------------------------

******* OleDbConnection conn;

public Form1()

{

InitializeComponent();

conn = new OleDbConnection();

conn.ConnectionString = @"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=d:\Database1.mdb";

conn.Open();

}

//it is for storing a file into database

******* void button1_Click(object sender, EventArgs e)

{

if (openFileDialog1.ShowDialog() == DialogResult.OK)

{

FileStream fs = new FileStream(openFileDialog1.FileName, FileMode.Open, FileAccess.Read);

Byte[] buff = new Byte[fs.Length];

BinaryReader rd = new BinaryReader(fs);

rd.Read(buff, 0, Convert.ToInt32(fs.Length));

OleDbCommand command = new OleDbCommand("INSERT INTO 表1 ([object], path) VALUES(@object, @path)", conn);

command.Parameters.Add("@object", OleDbType.Binary, buff.Length).Value = buff;

command.Parameters.Add("@path", OleDbType.Char, 255).Value = openFileDialog1.FileName;

command.ExecuteNonQuery();

rd.Close();

fs.Close();

}

}

******* void Form1_FormClosed(object sender, FormClosedEventArgs e)

{

conn.Close();

}

//it is for reading the data from the database and store it to a file

******* void button2_Click(object sender, EventArgs e)

{

OleDbCommand command = new OleDbCommand("SELECT [object], path FROM 表1", conn);

OleDbDataReader dr = command.ExecuteReader();

FileStream fs;

BinaryWriter writer;

int bufferSize = 100;

byte[] outByte = new byte[bufferSize];

while(dr.Read())

{

string filename = dr.GetString(1);

fs = new FileStream(filename, FileMode.OpenOrCreate, FileAccess.Write);

writer = new BinaryWriter(fs);

int startIndex = 0;

long retval = dr.GetBytes(0, startIndex, outByte, 0, bufferSize);

while (retval == bufferSize)

{

writer.Write(outByte);

writer.Flush();

startIndex += bufferSize;

retval = dr.GetBytes(0, startIndex, outByte, 0, bufferSize);

}

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

writer.Flush();

writer.Close();

fs.Close();

}

dr.Close();

}