急急急！怎么把数据库的img提出为string或者txt
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace GetImage
{
class Program
{
static void Main(string[] args)
{
private void GetImage()
{
string conn ="Server=(local);User id =sa;Pwd =huiheng518;dataset =test";
SqlConnection sqlCon = new Sqlconnection(conn);
string sql = "SELECT id,pic From Piclist where id=1";
SqlCommand myCommand = new SqlCommand();
myCommand.Connection = sqlCon;
myCommand.CommandType = CommandType.Text;
myCommand.CommandText = sql;
DataTable myTable = new DataTable();
SqlDataAdapter myDataAda = new SqlDataAdapter();
myDataAda.SelectCommand = myCommand;
try
{
sqlCon.Open();
myDataAda.Fill(myTable);
sqlCon.Close();
if(myTable.Rows.Count>0)
{
byte[] image = (byte[])myTable.Row[0]["ImageFile"];
string ll = Encoding.Default.GetString(image);
WriteStr(@"F:\test.txt",ll);
}
}
catch(Exception ex)
{

string err =ex.Message;
}
finally
{
sqlCon.Close();
myCommand.Dispose();
myDataAda.Dispose();
}
}
private void WriteStr(string strLogFileName,string strLogContent)
{
try
{
FileInfo objFileInfo = new FileInfo(strLogFileName);
using(FileStream objFileStream =objFileInfo.OpenWrite())
{
using (StreamWriter objStreamWriter = new StreamWrite())
{
objStreamWriter.BaseStream.Seek(0,SeekOrigin.End);
objStreamWriter.Writer("{0}",strLogContent);
}
}
}
catch
{
}
}

string ss = ReadStr(@"F:\test.txt");
byte[] b = Encoding.Default.GetBytes(ss);
string conn ="Server=(local);User id =sa;Pwd =huiheng518;dataset =test";
SqlConnection sqlCon = new SqlConnection(conn);
string sql = "update Piclist set ImageFile=@img where id = 1";
SqlCommand myCommand = new SqlCommand();
SqlParameter sp = new SqlParameter("@img",SqlDbType.Image);
myCommand.Connection = sqlCon;
myCommand.CommandType = CommandType.Text;
myCommand.CommandText = sql;
sp.Value = b;
myCommand.Parameters.Add(sp);
try

{
sqlCon.Open();
myCommand.ExecuteNonQuery();
sqlCon.Close();
}
catch(Exception eS)
{
string ee = eS.Message;
}
finally
{
sqlCon.Close();
myCommand.Dispose();

}
}
}
[解决办法]
Byte[] FileByteArray = new Byte[FileLength]; //图象文件临时储存Byte数组
Stream StreamObject = UpFile.InputStream; //建立数据流对像
//读取图象文件数据，FileByteArray为数据储存体，0为数据指针位置、FileLnegth为数据长度
StreamObject.Read(FileByteArray,0,FileLength);
//建立SQL Server链接
SqlConnection Con = new SqlConnection("Persist Security Info=False;User ID=sa;Initial Catalog=StudyTestData;Data Source=.");
String SqlCmd = "INSERT INTO ImageStore (ImageData, ImageContentType, ImageDescription, ImageSize) VALUES (@Image, @ContentType, @ImageDescription, @ImageSize)";
SqlCommand CmdObj = new SqlCommand(SqlCmd, Con);
CmdObj.Parameters.Add("@Image",SqlDbType.Binary, FileLength).Value = FileByteArray;
CmdObj.Parameters.Add("@ContentType", SqlDbType.VarChar,50).Value = UpFile.ContentType; //记录文件类型
//把其它单表数据记录上传
CmdObj.Parameters.Add("@ImageDescription", SqlDbType.VarChar,200).Value = txtDescription.Text;
//记录文件长度，读取时使用
CmdObj.Parameters.Add("@ImageSize", SqlDbType.BigInt,8).Value = UpFile.ContentLength;
Con.Open();
CmdObj.ExecuteNonQuery();
Con.Close();
txtMessage.Text = "<p><b>OK!你已经成功上传你的图片</b>";
//int ImgID = Convert.ToInt32(Request.QueryString["ImgID"]); //ImgID为图片ID
int ImgID=2;
//建立数据库链接
SqlConnection Con = new SqlConnection("Persist Security Info=False;User ID=sa;Initial Catalog=StudyTestData;Data Source=.");
String SqlCmd = "SELECT * FROM ImageStore WHERE ImageID = @ImageID";
SqlCommand CmdObj = new SqlCommand(SqlCmd, Con);
CmdObj.Parameters.Add("@ImageID", SqlDbType.Int).Value = ImgID;
Con.Open();
SqlDataReader SqlReader = CmdObj.ExecuteReader();
SqlReader.Read();
//Response.ContentType = (string)SqlReader["ImageContentType"];//设定输出文件类型
//输出图象文件二进制数制
Response.OutputStream.Write((byte[])SqlReader["ImageData"], 0, (int)SqlReader["ImageSize"]);

Response.End();
Con.Close();