bytes 与 string 互转,stream to Byte[]
Using System.Text;
byte[ ] 转换为string
byte[ ] image;
string ll = Encoding.Default.GetString(image);
string 转换为byte[ ]
string ss;
byte[] b = Encoding.Default.GetBytes(ss);
数据库中image类型的字段的处理。
首先我想从数据库中读出图片(以image类型存储的), 并且写入txt文件中:
private void GetImage()
{
string conn = "Server=192.168.0.11; User id=user; Pwd=pwd; Database=database";
SqlConnection sqlCon = new SqlConnection(conn);
string sql = "SELECT ImageFile, PersonID FROM Persons where PersonID = 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.Rows[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 StreamWriter(objFileStream))
{
objStreamWriter.BaseStream.Seek(0, SeekOrigin.End);
objStreamWriter.Write("{0}", strLogContent);
}
}
}
catch
{
}
}
其次,需要把图片从txt文件中读出然后存入数据库中。
string ss = ReadStr(@"F:\test.txt");
byte[] b = Encoding.Default.GetBytes(ss);
string conn = "Server=server; User id=user; Pwd=pwd; Database=database";
SqlConnection sqlCon = new SqlConnection(conn);
string sql = "update Persons set ImageFile=@img where PersonID = 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();
}
Stream To Byte[]
public static byte[] StreamToByte(Stream Reader)
{
try
{
MemoryStream mem = new MemoryStream(1024 * 500);
byte[] buffer = new byte[1024];
int bytesRead = 0;
int TotalByteRead = 0;
while (true)
{
bytesRead = Reader.Read(buffer, 0, buffer.Length);
if (bytesRead == 0)
break;
TotalByteRead += bytesRead;
mem.Write(buffer, 0, buffer.Length);
}
if (mem.Length > 0)
{
return mem.ToArray();
}
else
{
return null;
}
}
catch (Exception ep)
{
throw ep;
}
}
posted on 2010-09-30 16:05 jianshaohui 阅读(3397) 评论(0) 编辑 收藏 举报