最近我不得不在我的应用程序中使用 ExpandoObject,所以我想知道如何使用我的旧映射器也从 Dynamic ExpandoOnjects 进行映射,因为它无法映射 Expando 中的字段和属性。
代码:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
public class Mapper
{
private static readonly Dictionary<KeyValuePair<Type, Type>, object> Maps = new Dictionary<KeyValuePair<Type, Type>, object>();
private static PropertyInfo[] _fromProperties;
private static PropertyInfo[] _toProperties;
private static FieldInfo[] _fromFields;
private static FieldInfo[] _toFields;
// Rules...
private static readonly Func<PropertyInfo, PropertyInfo, bool> MatchingProps = (t1, t2) => t1.Name == t2.Name && t1.PropertyType.Name == t2.PropertyType.Name;
private static readonly Func<FieldInfo, FieldInfo, bool> MatchingFields = (t1, t2) => t1.Name == t2.Name && t1.FieldType.Name == t2.FieldType.Name;
private static readonly Func<PropertyInfo, FieldInfo, bool> MatchingPropertyToField = (t1, t2) => t1.Name == t2.Name && t1.PropertyType.Name == t2.FieldType.Name;
private static readonly Func<FieldInfo, PropertyInfo, bool> MatchingFieldToProperty = (t1, t2) => t1.Name == t2.Name && t1.FieldType.Name == t2.PropertyType.Name;
public static void AddMap<TFrom, TTo>(Action<TFrom, TTo> map = null)
where TFrom : class
where TTo : class { Maps.Add(new KeyValuePair<Type, Type>(typeof(TFrom), typeof(TTo)), map); }
public static void Map<TFromType, TOType>(TFromType @from, TOType to)
{
var key = new KeyValuePair<Type, Type>(typeof(TFromType), typeof(TOType));
var map = (Action<TFromType, TOType>)Maps[key];
bool hasMapping = Maps.Any(x => x.Key.Equals(key));
if (!hasMapping)
throw new Exception(string.Format("No map defined for {0} => {1}", typeof(TFromType).Name, typeof(TOType).Name));
Type tFrom = typeof(TFromType);
Type tTo = typeof(TOType);
_fromProperties = tFrom.GetProperties();
_fromFields = tFrom.GetFields();
_toProperties = tTo.GetProperties();
_toFields = tTo.GetFields();
SyncProperties(@from, to);
SyncFields(@from, to);
if (!Equals(map, null))
map(@from, to);
}
private static void SyncProperties<TFromType, TOType>(TFromType objFrom, TOType objTo)
{
PropertyInfo[] fromProperties = _fromProperties;
PropertyInfo[] toProperties = _toProperties;
FieldInfo[] toFields = _toFields;
if (fromProperties != null && fromProperties.Any()) {
foreach (PropertyInfo fromProperty in fromProperties) {
if (toProperties.Any(x => x.Name == fromProperty.Name)) {
PropertyInfo destinationProperty = toProperties.FirstOrDefault(x => x.Name == fromProperty.Name);
if (MatchingProps(fromProperty, destinationProperty)) {
object val = fromProperty.GetValue(objFrom, null);
if (Equals(val, null)) continue;
if (!Equals(destinationProperty, null)) destinationProperty.SetValue(objTo, Convert.ChangeType(val, fromProperty.PropertyType), null);
}
}
if (toFields.Any(x => x.Name == fromProperty.Name)) {
FieldInfo destinationField = toFields.FirstOrDefault(x => x.Name == fromProperty.Name);
if (MatchingPropertyToField(fromProperty, destinationField)) {
object val = fromProperty.GetValue(objFrom, null);
if (Equals(val, null)) continue;
if (!Equals(destinationField, null)) destinationField.SetValue(objTo, val);
}
}
}
}
}
private static void SyncFields<TFromType, TOType>(TFromType objFrom, TOType objTo)
{
FieldInfo[] fromFields = _fromFields;
FieldInfo[] toFields = _toFields;
PropertyInfo[] toProperties = _toProperties;
if (fromFields != null && fromFields.Any()) {
foreach (FieldInfo fromField in fromFields) {
if (toFields.Any(x => x.Name == fromField.Name)) {
FieldInfo destinationField = toFields.FirstOrDefault(x => x.Name == fromField.Name);
if (MatchingFields(fromField, destinationField)) {
object val = fromField.GetValue(objFrom);
if (Equals(val, null)) continue;
if (!Equals(destinationField, null)) destinationField.SetValue(objTo, val);
}
}
if (toProperties.Any(x => x.Name == fromField.Name)) {
PropertyInfo destinationProperty = toProperties.FirstOrDefault(x => x.Name == fromField.Name);
if (MatchingFieldToProperty(fromField, destinationProperty)) {
object val = fromField.GetValue(objFrom);
if (Equals(val, null)) continue;
if (!Equals(destinationProperty, null)) destinationProperty.SetValue(objTo, val, null);
}
}
}
}
}
}
用法:
static void Main()
{
dynamic o = new ExpandoObject();
o.Name = "Pouce";
o.Age = 42;
o.Rank = new Rank
{
Name = Ranks.Major
};
o.Guid = new Guid();
Soldier soldier = new Soldier();
Mapper.AddMap<ExpandoObject, Soldier>();
Mapper.Map(o, soldier);
Console.ReadLine();
}
public class Soldier
{
public string Name { get; set; }
public int Age { get; set; }
public Rank Rank { get; set; }
public Guid Guid { get; set; }
}
public class Rank
{
public Ranks Name { get; set; }
}
public enum Ranks
{
Private,
Specialist,
Corporal,
Sergeant,
Captain,
Major,
Colonel,
General
}
- [Q]:我如何使用我的映射器(上面介绍的)从 动态 ExpandoObject。
- [P]:问题是它在正常情况下完美工作
<object, object>
测绘;但是,当提供<ExpandoObject, object>
时 它没有映射任何东西。
最佳答案
这是因为 ExpandoObject
的属性不是真正的 .NET 属性。通过使用ExpandoObject
与 dynamic
关键字您可以为对象赋予任意属性,这是由 DLR
处理的在运行时。
您不能使用常规静态类型的方法 GetProperties()
和GetFields()
在 ExpandoObject
的动态实例上.
延长您的Mapper
消费ExpandObject
您必须将其视为特殊情况。
查看我的回答 here它可能对你有帮助。
编辑:反射(reflection) ExpandoObject
并不难。但是,您不会获得一组 PropertyInfo
或FieldInfo
从中。您只需得到KeyValuePair<string, object>
。因此,您可能必须添加这样的数组 KeyValuePair
来存储信息。
在您的 Map()
中方法,您可以检查 ExpandoObject
作为特殊情况:
if (tFrom == typeof(ExpandoObject)) {
_fromExpandoProperties = @from.Select(kvp => kvp).ToArray();
// where _fromExpandoProperties is of type KeyValuePair<string, object>[]
} else {
_fromProperties = tFrom.GetProperties();
}
要获取属性的名称和值,您可以使用 .Key
和.Value
而不是.PropertyType.Name
和.GetValue()
.
您必须在所有代码中考虑这种特化。
关于c# - 将动态 ExpandoObject 映射到对象,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/19574374/