Question

找到一个例子，我无法理解它的含义。

How can I read from a DataRow or a DataReader using the same code?

我不知道如何转换接口和两个类来回答C＃？

编辑：这是我要转换为C＃的代码：

Interface IIndexer
    Default ReadOnly Property Item(ByVal index As String)
End Interface

Class DataReaderWrapper
Implements IIndexer

Private ReadOnly _reader As IDataReader

Public Sub New(reader As IDataReader)
    _reader = reader
End Sub

Public ReadOnly Property Item(index As String) As Object Implements IIndexer.Item
    Get
        Return _reader(index)
    End Get
End Property
End Class

Class DataRowWrapper
Implements IIndexer

Private ReadOnly _row As DataRow

Public Sub New(row As DataRow)
    _row = row
End Sub

Public ReadOnly Property Item(index As String) As Object Implements IIndexer.Item
    Get
        Return _row(index)
    End Get
End Property
End Class

Answer 1

据我所知，没有相应的东西。有关Default关键字的详细信息，请访问MSDN。

您在这里看到的是Indexer in an Interface。

转换后的代码如下所示：

interface IIndexer
{
    object this[string index] { get; }
}

class DataReaderWrapper : IIndexer
{
    private readonly IDataReader _reader;
    public DataReaderWrapper(IDataReader reader)
    {
        _reader = reader;
    }

    public object this[string index]
    {
        get { return _reader[index]; }
    }
}

class DataRowWrapper : IIndexer
{
    private readonly DataRow _row;
    public DataRowWrapper(DataRow row)
    {
        _row = row;
    }

    public object this[string index]
    {
        get { return _row[index]; }
    }
}

Answer 2

像这样的东西会起作用，不清楚“默认属性”是什么意思：

var loadedItems = new List<Item>();
SqlDataReader dr = GetItemsDataReader();
while(dr.Read()){
  Item item = GetItemFromData(dr);
  loadedItems.Add(item);
}

private Item GetItemFromData(SqlDataReader dr){
  var loadedItem = new Item();
  loadedItem.ID = dr["ID"];
  loadedItem.Name = dr["Name"];
  'etc., etc.'
  Return loadedItem
}

什么是C＃中的VB默认属性？

2 个答案: