Question

我有windows phone 8本地数据库的问题。这就是我的数据库代码的外观：

  [Table(Name = "Folders")]
    public class FolderTable : INotifyPropertyChanged, INotifyPropertyChanging, IEqualityComparer<FolderTable>
    {
        private string _folderName;
        private string _description;
        private string _password;
        private string _tileColorName;

        [Column(IsPrimaryKey = true)]
        public string FolderName
        {
            get { return _folderName; }
            set
            {
                if (_folderName != value)
                {
                    NotifyPropertyChanging();
                    _folderName = value;
                    NotifyPropertyChanged();
                }
            }
        }

        [Column(CanBeNull = false)]
        public string Description
        {
            get { return _description; }
            set
            {
                if (_description != value)
                {
                    NotifyPropertyChanging();
                    _description = value;
                    NotifyPropertyChanged();
                }
            }
        }

        [Column]
        public string Password
        {
            get { return _password; }
            set
            {
                if (_password != value)
                {
                    NotifyPropertyChanging();
                    _password = value;
                    NotifyPropertyChanged();
                }
            }
        }

        [Column]
        public string TileColorName
        {
            get { return _tileColorName; }
            set
            {
                if (_tileColorName != value)
                {
                    NotifyPropertyChanging();
                    _tileColorName = value;
                    NotifyPropertyChanged();
                }
            }
        }

        private void NotifyPropertyChanging([CallerMemberName] string propertyName = "")
        {
            if ( PropertyChanging != null)
                PropertyChanging(this, new PropertyChangingEventArgs(propertyName));
        }

        private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
        {
            if ( PropertyChanged != null )
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }


        public event PropertyChangedEventHandler PropertyChanged;
        public event PropertyChangingEventHandler PropertyChanging;


        public bool Equals(FolderTable x, FolderTable y)
        {
            return x.FolderName == y.FolderName;
        }

        public int GetHashCode(FolderTable obj)
        {
            return obj.FolderName.GetHashCode();
        }
    }

文件夹添加：

    public Task Add(Folder folder)
    {
        var folderTable = GetFolderTable(folder);

        _databaseContext.Folders.InsertOnSubmit(folderTable);

        return Task.FromResult(true);
    }

提交：

public Task Commit()
{
    try
    {
        _databaseContext.Folders.Context.SubmitChanges();
    }
    catch (DuplicateKeyException duplicateKeyException)
    {
        _databaseContext.Dispose();
        _databaseContext = new FolderDbContext(FolderDbContext.DBConnectionString);

        throw new FolderAlreadyExistsException(duplicateKeyException);
    }

    return Task.FromResult(true);
}

当我Add新文件夹（之前不存在具有此类名称的文件夹），Commit然后我尝试添加具有相同名称DuplicateKeyException的文件夹时，将被抛出并正确处理。但是，在catch部分重新创建上下文后，下一次调用具有相同名称的Add和Commit文件夹会抛出SqlCeException消息："A duplicate value cannot be inserted into a unique index. [ Table name = Folders,Constraint name = PK_Folders ]"。这是正常的行为还是我做错了什么？在什么情况下抛出DuplicateKeyException？如何抓住SqlCeException？我甚至看不到System.Data.SqlServerCe名称空间。

Answer 1

如果您希望明确捕获SqlCeException，请使用反射来获取示例的类型名称：

ex.GetType().Name == "SqlCeException"

DuplicateKeyException和SqlCeException SQL Ce WP8

1 个答案: