c# - 比较c#中的对象属性

关闭。这个问题是 opinion-based 。它目前不接受答案。




2年前关闭。










锁定。这个问题及其答案是 locked 因为这个问题是题外话但具有历史意义。它目前不接受新的答案或互动。








这就是我想出的作为我的许多其他类继承的类的方法。这个想法是它允许在相同类型的对象的属性之间进行简单的比较。

现在，这确实有效 - 但为了提高我的代码质量，我想我会把它扔掉进行审查。它如何更好/更有效/等等？

/// <summary>
/// Compare property values (as strings)
/// </summary>
/// <param name="obj"></param>
/// <returns></returns>
public bool PropertiesEqual(object comparisonObject)
{

    Type sourceType = this.GetType();
    Type destinationType = comparisonObject.GetType();

    if (sourceType == destinationType)
    {
        PropertyInfo[] sourceProperties = sourceType.GetProperties();
        foreach (PropertyInfo pi in sourceProperties)
        {
            if ((sourceType.GetProperty(pi.Name).GetValue(this, null) == null && destinationType.GetProperty(pi.Name).GetValue(comparisonObject, null) == null))
            {
                // if both are null, don't try to compare  (throws exception)
            }
            else if (!(sourceType.GetProperty(pi.Name).GetValue(this, null).ToString() == destinationType.GetProperty(pi.Name).GetValue(comparisonObject, null).ToString()))
            {
                // only need one property to be different to fail Equals.
                return false;
            }
        }
    }
    else
    {
        throw new ArgumentException("Comparison object must be of the same type.","comparisonObject");
    }

    return true;
}

最佳答案

我正在寻找一段代码来帮助编写单元测试。这是我最终使用的。

public static bool PublicInstancePropertiesEqual<T>(T self, T to, params string[] ignore) where T : class
  {
     if (self != null && to != null)
     {
        Type type = typeof(T);
        List<string> ignoreList = new List<string>(ignore);
        foreach (System.Reflection.PropertyInfo pi in type.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance))
        {
           if (!ignoreList.Contains(pi.Name))
           {
              object selfValue = type.GetProperty(pi.Name).GetValue(self, null);
              object toValue = type.GetProperty(pi.Name).GetValue(to, null);

              if (selfValue != toValue && (selfValue == null || !selfValue.Equals(toValue)))
              {
                 return false;
              }
           }
        }
        return true;
     }
     return self == to;
  }

编辑:

与上面相同的代码，但使用 LINQ 和扩展方法:

public static bool PublicInstancePropertiesEqual<T>(this T self, T to, params string[] ignore) where T : class
{
    if (self != null && to != null)
    {
        var type = typeof(T);
        var ignoreList = new List<string>(ignore);
        var unequalProperties =
            from pi in type.GetProperties(BindingFlags.Public | BindingFlags.Instance)
            where !ignoreList.Contains(pi.Name) && pi.GetUnderlyingType().IsSimpleType() && pi.GetIndexParameters().Length == 0
            let selfValue = type.GetProperty(pi.Name).GetValue(self, null)
            let toValue = type.GetProperty(pi.Name).GetValue(to, null)
            where selfValue != toValue && (selfValue == null || !selfValue.Equals(toValue))
            select selfValue;
        return !unequalProperties.Any();
    }
    return self == to;
}

public static class TypeExtensions
   {
      /// <summary>
      /// Determine whether a type is simple (String, Decimal, DateTime, etc)
      /// or complex (i.e. custom class with public properties and methods).
      /// </summary>
      /// <see cref="http://stackoverflow.com/questions/2442534/how-to-test-if-type-is-primitive"/>
      public static bool IsSimpleType(
         this Type type)
      {
         return
            type.IsValueType ||
            type.IsPrimitive ||
            new[]
            {
               typeof(String),
               typeof(Decimal),
               typeof(DateTime),
               typeof(DateTimeOffset),
               typeof(TimeSpan),
               typeof(Guid)
            }.Contains(type) ||
            (Convert.GetTypeCode(type) != TypeCode.Object);
      }

      public static Type GetUnderlyingType(this MemberInfo member)
      {
         switch (member.MemberType)
         {
            case MemberTypes.Event:
               return ((EventInfo)member).EventHandlerType;
            case MemberTypes.Field:
               return ((FieldInfo)member).FieldType;
            case MemberTypes.Method:
               return ((MethodInfo)member).ReturnType;
            case MemberTypes.Property:
               return ((PropertyInfo)member).PropertyType;
            default:
               throw new ArgumentException
               (
                  "Input MemberInfo must be if type EventInfo, FieldInfo, MethodInfo, or PropertyInfo"
               );
         }
      }
   }

关于c# - 比较c#中的对象属性，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/506096/