c# - 比较两个对象的值而不列出每一列

Question

Web 服务导入数据并存储在业务逻辑 Graph.AddressList 中。如果找到匹配项，则添加到 keepList。问题是数据完全相同，但没有添加到保留列表中。例如，数据库中记录中的 ENTITYKEY 会被填充，但不会在 Xml 中填充，而无需写出数据库中的每一列以匹配 xmlRecord 中的每一列。有解决办法吗？

// Fetch List Of Addresses
List<Address> updateAddressList = DbContext.GraphAddressList.Where<Address>(p => p.PersonnelNo == action.PersonnelNo).ToList<Address>();

////IF ADDRESS EXISTS IN THE DB, BUT NOT IN THE XML FILE, REMOVE FROM DB
List<Address> keepList = new List<Address>();
foreach (Address recordInDB in updateAddressList)
{
    foreach (Address_0006 recordInXML in Graph.AddressList)
    {
        if (recordInDB == recordInXML)
        {                                                        
            keepList.Add(recordInDB);
        }
    }
}

List<Address> removeList = updateAddressList.Except(keepList).ToList();
foreach (Address record in removeList)
{                                           
    DbContext.AddressList.DeleteObject(record);
}

感谢您的回复，所以我真的需要创建一个类

 public override bool Equals(object obj)
{
    var item = obj as RecommendationDTO;

    if (item == null)
    {
        return false;
    }

    return this.RecommendationId.Equals(item.RecommendationId);
}

public override int GetHashCode()
{
    return this.RecommendationId.GetHashCode();
}

Answer 1

recordInDB和 recordInXML是自定义对象，要检查它们是否相等，您必须:

1. 覆盖 Equals和 GetHashCode对于他们:Correct way to override Equals() and GetHashCode()
2. 实现 IEqualityComparer : How to use the IEqualityComparer
3. 让你的一个类(class)实现IEquatable<T>其中 T是其他类的类型

这样做，对象将根据它们具有的属性进行比较。目前 ( x == y ) 检查的是引用是否相等——这是两个不同的实例意味着 false .这样做之后，比较时你也应该使用 recordInDB.Equals(recordInXML)

实现之后你还可以重构一下:

var keepList = recordInDB.Where(record => Graph.AddressList.Contains(record));
var removeList = updateAddressList.Except(keepList).ToList();
foreach (Address record in removeList)
{                                           
    DbContext.AddressList.DeleteObject(record);
}

---

然后在您的 Address_0006 中选择选项 3实现IEquatable<Address> :

public class Address_0006 : IEquatable<Address>
{
    public bool Equals(Address other)
    {
        // Compare here that each of the relevant properties in this (Address_0006) 
        // equals the corresponding property in other (Address)
    }
}