/// <summary>
/// 附加数据库
/// </summary>
/// <returns></returns>
private bool Attachdb()
{
 try
 { 
  string sql = string.Empty;
  if (File.Exists(sMDBFile))
  {
   sql = "EXEC sp_attach_db @dbname = '" + txtDBName.Text + 
     "', @filename1 = '" + sMDBFile+
     "',@filename2='" + sLog + "'";
   SqlConnection conn = new SqlConnection(string.Format("Data Source={0};Initial Catalog=master;User ID={1};PWD={2}","(local)","sa","pwd"));
   using (conn)
   {
    lock (conn)
    {
     conn.Open();
     SqlCommand cmd = new SqlCommand(sql, conn);
     cmd.ExecuteNonQuery();
    }
   }
  }
  return true;
 }
 catch
 {
  return false;
 }
}
//sMDBFile 为mdf文件路径
//sLog 为ldf文件路径