初学三层结构问题

private string _yusitem;

private string _yfitem;

/// <summary>

///

/// </summary>

public string curr

{

set{ _curr=value;}

get{return _curr;}

}

/// <summary>

///

/// </summary>

public string name

{

set{ _name=value;}

get{return _name;}

}

/// <summary>

///

/// </summary>

public decimal rate

{

set{ _rate=value;}

get{return _rate;}

}

/// <summary>

///

/// </summary>

public decimal rate1

{

set{ _rate1=value;}

get{return _rate1;}

}

/// <summary>

///

/// </summary>

public string ybitem

{

set{ _ybitem=value;}

get{return _ybitem;}

}

/// <summary>