/// <summary>
 /// 全构造函数
 /// </summary>
 public SystemAttachmentContentEntity(int id, SystemAttachmentEntity attacmentID, byte[] fileContent)
 {
     _id          = id;
     _attacmentID = attacmentID;
     _fileContent = fileContent;
 }
 /// <summary>
 /// 默认构造函数
 /// </summary>
 public SystemAttachmentContentEntity()
 {
     _id          = 0;
     _attacmentID = null;
     _fileContent = new byte[1];
 }