如何获取Oracle数据库中的CLOB字段的值,为什么我得到的是乱码一堆,不管存入表中的是中文还是英文.

[Jelly1016]

下面存入数据时的代码:
System.Text.Encoding unicode=System.Text.Encoding.UTF8;
byte[] tempbuff=unicode.GetBytes(strValue);
OracleConnection cnn=new OracleConnection(DataAccessOracle.cnnstring);
cnn.Open();
OracleTransaction tx = cnn.BeginTransaction();
OracleCommand cmd = cnn.CreateCommand();
cmd.Transaction = tx;
cmd.Connection=cnn;
cmd.CommandText = "declare xx blob; begin dbms_lob.createtemporary(xx, false, 0); :tempblob := xx; end;";
cmd.Parameters.Add(new OracleParameter("tempblob", OracleType.Blob)).Direction = ParameterDirection.Output;
cmd.ExecuteNonQuery();

OracleLob tempLob=(OracleLob)cmd.Parameters[0].Value;
tempLob.BeginBatch(OracleLobOpenMode.ReadWrite);
tempLob.Write(tempbuff,0,tempbuff.Length);
tempLob.EndBatch();

string strOracle="insert into pmis.zzzz(id,name,value1) values(4,'z',:value1)";

OracleParameter objPara=new OracleParameter("value1",OracleType.Clob);
objPara.Value=tempLob;
cmd=new OracleCommand(strOracle,cnn);
cmd.Parameters.Add(objPara);
cmd.Transaction=tx;
cmd.ExecuteNonQuery();
tx.Commit();
cnn.Close();

读取时的代码：
OracleConnection cnn=new OracleConnection(DataAccessOracle.cnnstring);
cnn.Open();
OracleTransaction tx = cnn.BeginTransaction();
OracleCommand cmd = new OracleCommand("select * from pmis.zzzz where id=4",cnn);
cmd.Transaction=tx;
OracleDataReader dr = cmd.ExecuteReader();
dr.Read();
MessageBox.Show(dr.GetOracleLob(2).Value.ToString());
tx.Commit();
dr.Close();
cnn.Close();

无论我输入时用ＧＢ２３１２还是Unicode还是UTF8显示时都是乱码，在sqlplus显示时也是乱码，请教高手如何解决这个问题，是不是存入表中的时候编码就不对？
这个问题已经折磨我好长时间了，我很急于解决，先谢了！

[jellypudding]

public static void WriteLob(string table_name,string table_id,int id,int column,string content)
{
OracleConnection myCn = new OracleConnection(cnnstring);
OracleCommand myCmd = new OracleCommand();
try
{
myCn.Open();
}
catch(System.Data.OracleClient.OracleException e)
{
throw new Exception(e.Message);
}
OracleTransaction myTrans = myCn.BeginTransaction();
try
{
myCmd.Connection = myCn;
myCmd.Transaction = myTrans;

myCmd.CommandText = "SELECT * FROM "+ table_name +" where "+ table_id +" = "+ id +" FOR UPDATE";
OracleDataReader reader = myCmd.ExecuteReader();
using(reader)
{
reader.Read();
OracleLob CLOB = reader.GetOracleLob(column);//column为lob类型所在列

Encoding unicode=Encoding.Unicode;
byte[] buffer=unicode.GetBytes(content);

if(buffer.Length % 2 ==0)
CLOB.Write(buffer, 0, buffer.Length); //这里的参数必须为偶数
else
CLOB.Write(buffer, 0, (buffer.Length - 1));
//CLOB.Position = 0;
myTrans.Commit();
}
}
catch(System.Data.OracleClient.OracleException e)
{
myTrans.Rollback();
throw new Exception(e.Message);
}
catch(Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}
public static string ReadLob(string table_name,string table_id,int id,int column)
{
OracleConnection myCn = new OracleConnection(cnnstring);
OracleCommand myCmd = new OracleCommand();
try
{
myCn.Open();
}
catch(System.Data.OracleClient.OracleException e)
{
throw new Exception(e.Message);
}
OracleTransaction myTrans = myCn.BeginTransaction();
try
{
myCmd.Connection = myCn;
myCmd.Transaction = myTrans;
myCmd.CommandText = "SELECT * FROM "+ table_name +" where "+ table_id +" = "+ id +" FOR UPDATE";
OracleDataReader reader = myCmd.ExecuteReader();
using(reader)
{
reader.Read();
OracleLob CLOB = reader.GetOracleLob(column);
int[] content = new int[(int)CLOB.Length];
byte[] buffer = new byte[(int)CLOB.Length];

CLOB.Read(buffer,0,(int)CLOB.Length);

Encoding unicode=Encoding.Unicode;
string final=unicode.GetString(buffer);

myTrans.Commit();
return final;
}
}
catch(System.Data.OracleClient.OracleException e)
{
myTrans.Rollback();
throw new Exception(e.Message);
}
finally
{
myCmd.Dispose();
myCn.Close();
}
}
}