c# - 计算对象中所有字符串属性的总长度

Question

我有一个具有 100 多个属性的对象。它们都是字符串。如何计算所有属性放在一起的总长度？

我的尝试:

    public static int GetPropertiesMaxLength(object obj)
    {
        int totalMaxLength=0;
        Type type = obj.GetType();
        PropertyInfo[] info = type.GetProperties();
        foreach (PropertyInfo property in info)
        {
           // ? 
            totalMaxLength+=??
        }
        return totalMaxLength;
    }

建议？

Answer 1

使用 LINQ Sum()和 Where()方法:

public static int GetTotalLengthOfStringProperties(object obj)
{            
    Type type = obj.GetType();
    IEnumerable<PropertyInfo> info = type.GetProperties();

    int total = info.Where(p => p.PropertyType == typeof (String))
                    .Sum(pr => (((String) pr.GetValue(obj, null)) 
                               ?? String.Empty).Length);
    return total;
}

PS:要启用 LINQ，您必须添加using System.Linq；

编辑:更通用的方法

/// <summary>
/// Gets a total length of all string-type properties
/// </summary>
/// <param name="obj">The given object</param>
/// <param name="anyAccessModifier">
/// A value which indicating whether non-public and static properties 
/// should be counted
/// </param>
/// <returns>A total length of all string-type properties</returns>
public static int GetTotalLengthOfStringProperties(
                                  object obj, 
                                  bool anyAccessModifier)
{
    Func<PropertyInfo, Object, int> resolveLength = (p, o) =>        
        ((((String) p.GetValue(o, null))) ?? String.Empty).Length;

    Type type = obj.GetType();
    IEnumerable<PropertyInfo> info = anyAccessModifier 
        ? type.GetProperties(BindingFlags.NonPublic | BindingFlags.Public | 
                             BindingFlags.Instance | BindingFlags.Static)
        : type.GetProperties();    

    int total = info.Where(p => p.PropertyType == typeof (String))
                    .Sum(pr => resolveLength(pr, obj));
    return total;
}