代码契约和接口继承的奇怪警告/错误

Question

作为主题，我遇到了代码契约和接口的严重警告/错误。 这里是我的场景

主接口

[ContractClass(typeof(DTOInfoContract))]
public interface IDTOInfo
{
    int ID { get; }
    string Description { get; }        
    string LinkText { get; }
    string Title { get; }

    void DTOInit(int id, string title, string descr, string linkText);
}

辅助接口

[ContractClass(typeof(DTONewsContract))]
public interface IDTONews : IDTOInfo
{    
}

[ContractClass(typeof(DTOPromoContract))]
public interface IDTOPromo : IDTOInfo
{                
    string Photo { get; }

    void DTOPromoInit(int id, string title, string descr, string linkText, string Photo);

然后是我的合同

[ContractClassFor(typeof(IDTOInfo))]
public abstract class DTOInfoContract : IDTOInfo
{
    int IDTOInfo.ID
    {
        get { Contract.Ensures(Contract.Result<int>() > 0, "Returned value is out of Range"); return default(int); }
    }

    string IDTOInfo.Description
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.LinkText
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.Title
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    void IDTOInfo.DTOInit(int id, string title, string descr, string linkText)
    {
        Contract.Requires<ArgumentOutOfRangeException>(id > 0, "id has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(title), "titolo has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(descr), "descr has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(linkText), "linkText has no valid value");
    }
}


}


[ContractClassFor(typeof(IDTONews))]
public abstract class DTONewsContract : IDTONews
{
    int IDTOInfo.ID
    {
        get { Contract.Ensures(Contract.Result<int>() > 0, "Returned value is out of Range"); return default(int); }
    }

    string IDTOInfo.Description
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.linkText
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.Title
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    void IDTOInfo.DTOInit(int id, string title, string descr, string linkText)
    {
        Contract.Requires<ArgumentOutOfRangeException>(id > 0, "id has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(title), "title has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(descr), "descr has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(linkText), "linkText has no valid value");
    }
}


[ContractClassFor(typeof(IDTOPromo))]
public abstract class DTOPromoContract : IDTOPromo
{        
    string IDTOPromo.Photo
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }        

    void IDTOPromo.DTOPromoInit(int id, string title, string descr, string linkText, string photo)
    {
        Contract.Requires<ArgumentOutOfRangeException>(id > 0, "id has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(title), "title has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(descr), "descr has no valid value");                  
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(linkText), "linkText has no valid value");
    }

    int IDTOInfo.ID
    {
        get { Contract.Ensures(Contract.Result<int>() > 0, "Returned value is out of Range"); return default(int); }
    }

    string IDTOInfo.Description
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.LinkText
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    string IDTOInfo.Title
    {
        get { Contract.Ensures(!String.IsNullOrEmpty(Contract.Result<string>()), "Returned value is out of Range"); return default(string); }
    }

    void IDTOInfo.DTOInit(int id, string title, string descr, string linkText)
    {
        Contract.Requires<ArgumentOutOfRangeException>(id > 0, "id has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(title), "title has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(descr), "descr has no valid value");
        Contract.Requires<ArgumentOutOfRangeException>(!String.IsNullOrEmpty(linkText), "linkText has no valid value");
    }
}

在这种情况下我只有一些警告，如下所示

warning CC1076: Contract class DTOPromoContract cannot define contract for method IDTOInfo.get_ID as its original definition is not in type IDTOPromo. Define the contract on type IDTOInfo instead.

但是，如果我尝试删除 IDTONews 和 IDTOPromo 合同类中的 IDTOInfo 方法和属性，则错误是，例如，以下

Error   40 'DTOPromoContract' does not implement the member of interface 'IDTOInfo.Description' 

是不是很奇怪的情况？ 有没有一种解决方案可以将代码契约和接口与之前的场景进行最佳组合？

谢谢你！

Answer 1

契约类应该只指定它们所附加的接口的行为，而不是任何基接口。

因此，在DTOPromoContract和DTONewsContract中，所有从IDTOInfo继承的方法都应该是abstract。 （所有接口契约类也应该是抽象的。）