wp8本地數據庫問題

Question

我在windows phone 8應用程序中創建了本地數據庫。我有4個領域。

userID - int 
Username - string 
FileName - string 
FileByte - byte[] 

我在做的是試圖更新FileByte列。但是，當我更新的專欄中，我得到異常SQL Server does not handle comparison of NText, Text, Xml, or Image data types.

這裏是我的DataTable

[Table] 
public class UserFilesDetailsTable : INotifyPropertyChanged, INotifyPropertyChanging 
{ 
    // Define ID: private field, public property, and database column. 
    private int _userID; 
    [Column(IsPrimaryKey = true, IsDbGenerated = true, DbType = "INT NOT NULL Identity", CanBeNull = false, AutoSync = AutoSync.OnInsert)] 
    public int userID 
    { 
     get { return _userID; } 
     set 
     { 
      if (_userID != value) 
      { 
       NotifyPropertyChanging("userID"); 
       _userID = value; 
       NotifyPropertyChanged("userID"); 
      } 
     } 
    } 

    // Define item name: private field, public property, and database column. 
    private string _Username; 
    [Column(DbType = "NVarChar(100) NOT NULL", CanBeNull = false)] 
    public string Username 
    { 
     get { return _Username; } 
     set 
     { 
      if (_Username != value) 
      { 
       NotifyPropertyChanging("Username"); 
       _Username = value; 
       NotifyPropertyChanged("Username"); 
      } 
     } 
    } 

    // Define item name: private field, public property, and database column. 
    private string _Filename; 
    [Column(DbType = "NVarChar(100) NOT NULL", CanBeNull = false)] 
    public string Filename 
    { 
     get { return _Filename; } 
     set 
     { 
      if (_Filename != value) 
      { 
       NotifyPropertyChanging("Filename"); 
       _Filename = value; 
       NotifyPropertyChanged("Filename"); 
      } 
     } 
    } 

    // Define item name: private field, public property, and database column. 
    private byte[] _Filebytes; 
    [Column(DbType = "image")] 
    public byte[] Filebytes 
    { 
     get { return _Filebytes; } 
     set 
     { 
      if (_Filebytes != value) 
      { 
       NotifyPropertyChanging("Filebytes"); 
       _Filebytes = value; 
       NotifyPropertyChanged("Filebytes"); 
      } 
     } 
    } 

    #region INotifyPropertyChanged Members 

    public event PropertyChangedEventHandler PropertyChanged; 

    // Used to notify that a property changed 
    private void NotifyPropertyChanged(string propertyName) 
    { 
     if (PropertyChanged != null) 
     { 
      PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 
     } 
    } 

    #endregion 

    #region INotifyPropertyChanging Members 

    public event PropertyChangingEventHandler PropertyChanging; 

    // Used to notify that a property is about to change 
    private void NotifyPropertyChanging(string propertyName) 
    { 
     if (PropertyChanging != null) 
     { 
      PropertyChanging(this, new PropertyChangingEventArgs(propertyName)); 
     } 
    } 

    #endregion 
} 

這裏我更新查詢

public void addFiles(int userID, string userName, string fileName, byte[] fileBytes) 
    { 
     try 
     { 
      if (!(databaseTablesDB.usersFileDetailsTable.Where(f => f.Filename == fileName).Any())) 
      { 
       databaseTablesDB.usersFileDetailsTable.InsertOnSubmit(new UserFilesDetailsTable { userID = userID, Username = userName, Filename = fileName, Filebytes = fileBytes }); 
       // Save changes to the database. 
       databaseTablesDB.SubmitChanges(); 
      } 
      else 
      { 
       var fileDetails = (from file in databaseTablesDB.usersFileDetailsTable where file.Filename == fileName && file.Username == userName select file).FirstOrDefault(); 
       if (fileDetails != null) 
       { 
        fileDetails.Filebytes = fileBytes; 
       } 
       databaseTablesDB.SubmitChanges(); 
      } 
     } 
     catch (Exception ex) 
     { 

     } 
    } 

我沒有得到哪裏是問題。有人可以幫助解決這個問題嗎？

Answer 1

看看SQL Server does not handle comparison of NText, Text, Xml, or Image data types。它建議您將FileByte列的類型更改爲VARBINARY（MAX）。