public static void ResolveDtoMaps(this IMapperConfigurationExpression mapper)
{
var types = GetAllDtos();
foreach (var type in types)
{
var dto = Activator.CreateInstance(type);
var interfaces = type.GetInterfaces().Where(t2 => t2.IsGenericType && t2.GetGenericTypeDefinition() == typeof(IDto <,>));
foreach (var @interface in interfaces)
{
var genericBackArguments = @interface.GetGenericArguments();
var genericArguments = genericBackArguments.Reverse().ToArray();
if (genericArguments.Length < 2)
{
continue;
}
var createMaps = mapper.GetType().GetMethods().First(t => t.Name == "CreateMap" && t.IsGenericMethod);
var map = createMaps.MakeGenericMethod(genericArguments).Invoke(mapper, null);
var mapConfig = Activator.CreateInstance(typeof(Maps <,>).MakeGenericType(genericBackArguments), map);
type.GetMethod(nameof(IDto <object, object> .MapExpandables)).Invoke(dto, new[] { mapConfig });
type.GetMethod(nameof(IDto <object, object> .Map)).Invoke(dto, new[] { mapConfig });
var mapBack = createMaps.MakeGenericMethod(genericBackArguments).Invoke(mapper, null);
var mapBackConfig = Activator.CreateInstance(typeof(Maps <,>).MakeGenericType(genericArguments), mapBack);
type.GetMethod(nameof(IDto <object, object> .MapBack)).Invoke(dto, new[] { mapBackConfig });
}
}
}
public static void CreateAutoAttributeMaps(this IMapperConfigurationExpression configuration, Type type, Type[] targetTypes, MemberList memberList)
{
//获取源中具有automapkeyattribute的所有属性
var sourceKeysPropertyInfo = type.GetProperties()
.Where(w => w.GetCustomAttribute <AutoMapKeyAttribute>() != null)
.Select(s => s).ToList();
foreach (var targetType in targetTypes)
{
if (!sourceKeysPropertyInfo.Any())
{
configuration.CreateMap(type, targetType, memberList);
continue;
}
BinaryExpression equalityComparer = null;
//在lambda表达式中表示源示例：（source）=>…
ParameterExpression sourceParameterExpression = Expression.Parameter(type, "source");
//在lambda表达式中表示目标示例：（target）=>…
ParameterExpression targetParameterExpression = Expression.Parameter(targetType, "target");
//我们可以使用多个automapkey来比较
foreach (PropertyInfo propertyInfo in sourceKeysPropertyInfo)
{
//在lambda表达式中表示参数的特定属性示例：（source）=>source.id
MemberExpression sourcePropertyExpression = Expression.Property(sourceParameterExpression, propertyInfo);
//为目标查找与之比较的同名属性
//例如，如果我们在源代码中有属性id上的attribut automapkey，那么我们希望在目标中获取要比较的id，而不是
var targetPropertyInfo = targetType.GetProperty(sourcePropertyExpression.Member.Name);
//如果目标中不存在automapkeyattribute为的属性，则会发生这种情况
if (targetPropertyInfo is null)
{
continue;
}
//在lambda表达式中，表示参数的特定属性示例：（target）=>target.id
MemberExpression targetPropertyExpression = Expression.Property(targetParameterExpression, targetPropertyInfo);
//比较源中automapkey定义的属性与目标中的属性不同
//示例（source，target）=>source.id==target.id
BinaryExpression equal = Expression.Equal(sourcePropertyExpression, targetPropertyExpression);
if (equalityComparer is null)
{
equalityComparer = equal;
}
else
{
//如果我们比较多个键，我们要在
//Exemple : (source, target) => source.Email == target.Email && source.UserName == target.UserName
equalityComparer = Expression.And(equalityComparer, equal);
}
}
//如果目标中没有匹配的automapkey
//在这种情况下，我们添加默认映射
if (equalityComparer is null)
{
configuration.CreateMap(type, targetType, memberList);
continue;
}
//我们需要使func<sourcetype，targettype，bool>的泛型类型来调用后面的expression.lambda
var funcGenericType = typeof(Func <, ,>).MakeGenericType(type, targetType, typeof(bool));
//生成表达式的方法信息。lambda<func<sourceType，targetType，bool>>稍后调用
var lambdaMethodInfo = typeof(Expression).GetMethod("Lambda", 2, 1).MakeGenericMethod(funcGenericType);
//调用expression.lambda
var expressionLambdaResult = lambdaMethodInfo.Invoke(null, new object[] { equalityComparer, new ParameterExpression[] { sourceParameterExpression, targetParameterExpression } });
//获取imapperConfigurationExpression.createMap<source，target>
var createMapMethodInfo = configuration.GetType().GetMethod("CreateMap", 1, 2).MakeGenericMethod(type, targetType);
//调用configuration.createmap<source，target>（）。
var createMapResult = createMapMethodInfo.Invoke(configuration, new object[] { memberList });
var autoMapperCollectionAssembly = Assembly.Load("AutoMapper.Collection");
var autoMapperCollectionTypes = autoMapperCollectionAssembly.GetTypes();
var equalityComparisonGenericMethodInfo = autoMapperCollectionTypes
.Where(w => !w.IsGenericType && !w.IsNested)
.SelectMany(s => s.GetMethods()).Where(w => w.Name == "EqualityComparison")
.FirstOrDefault()
.MakeGenericMethod(type, targetType);
//调用EqualityComparison
//Exemple configuration.CreateMap<Source, Target>().EqualityComparison((source, target) => source.Id == target.Id)
equalityComparisonGenericMethodInfo.Invoke(createMapResult, new object[] { createMapResult, expressionLambdaResult });
}
}
/// <summary>
/// 创建映射
/// </summary>
/// <param name="configuration"></param>
/// <param name="type">原始类</param>
/// <param name="targetTypes">目标类列表</param>
/// <param name="memberList">成员类型，是Source还是Destination，用来验证字段已经全部映射完毕</param>
public static void CreateAutoAttributeMaps(this IMapperConfigurationExpression configuration, Type type, Type[] targetTypes, MemberList memberList)
{
//Get all the properties in the source that have the AutoMapKeyAttribute
var sourceKeysPropertyInfo = type.GetProperties()
.Where(w => w.GetCustomAttribute <AutoMapKeyAttribute>() != null)
.Select(s => s).ToList();
foreach (var targetType in targetTypes)
{
//这里表示，当前类打了自动映射的标签，且类里面的字段都没有打映射主键标签，那么当前类就直接进行映射
if (!sourceKeysPropertyInfo.Any())
{
configuration.CreateMap(type, targetType, memberList);
continue;
}
BinaryExpression equalityComparer = null;
//In a lambda expression represent the source example : (source) => ...
ParameterExpression sourceParameterExpression = Expression.Parameter(type, "source");
//In a lambda expression represent the target example : (target) => ...
ParameterExpression targetParameterExpression = Expression.Parameter(targetType, "target");
//We could use multiple AutoMapKey to compare the determine equality
//遍历那些打了自动映射键的字段，根据属性的键进行匹配，匹配上了的才进行赋值
foreach (PropertyInfo propertyInfo in sourceKeysPropertyInfo)
{
//In a lambda expression represent a specific property of a parameter example : (source) => source.Id
MemberExpression sourcePropertyExpression = Expression.Property(sourceParameterExpression, propertyInfo);
//Find the target a property with the same name to compare with
//Example if we have in source the attribute AutoMapKey on the Property Id we want to get Id in the target to compare against
var targetPropertyInfo = targetType.GetProperty(sourcePropertyExpression.Member.Name);
//It happen if the property with AutoMapKeyAttribute does not exist in target
if (targetPropertyInfo is null)
{
continue;
}
//In a lambda expression represent a specific property of a parameter example : (target) => target.Id
MemberExpression targetPropertyExpression = Expression.Property(targetParameterExpression, targetPropertyInfo);
//Compare the property defined by AutoMapKey in the source against the same property in the target
//Example (source, target) => source.Id == target.Id
BinaryExpression equal = Expression.Equal(sourcePropertyExpression, targetPropertyExpression);
if (equalityComparer is null)
{
equalityComparer = equal;
}
else
{
//If we compare multiple key we want to make an and condition between
//Example : (source, target) => source.Email == target.Email && source.UserName == target.UserName
equalityComparer = Expression.And(equalityComparer, equal);
}
}
//If there is not match for AutoMapKey in the target
//In this case we add the default mapping
if (equalityComparer is null)
{
configuration.CreateMap(type, targetType, memberList);
continue;
}
//We need to make a generic type of Func<SourceType, TargetType, bool> to invoke later Expression.Lambda
var funcGenericType = typeof(Func <, ,>).MakeGenericType(type, targetType, typeof(bool));
//Make a method info of Expression.Lambda<Func<SourceType, TargetType, bool>> to call later
var lambdaMethodInfo = typeof(Expression).GetMethod("Lambda", 2, 1).MakeGenericMethod(funcGenericType);
//Make the call to Expression.Lambda
var expressionLambdaResult = lambdaMethodInfo.Invoke(null, new object[] { equalityComparer, new ParameterExpression[] { sourceParameterExpression, targetParameterExpression } });
//Get the method info of IMapperConfigurationExpression.CreateMap<Source, Target>
var createMapMethodInfo = configuration.GetType().GetMethod("CreateMap", 1, 2).MakeGenericMethod(type, targetType);
//Make the call to configuration.CreateMap<Source, Target>().
var createMapResult = createMapMethodInfo.Invoke(configuration, new object[] { memberList });
var autoMapperCollectionAssembly = Assembly.Load("AutoMapper.Collection");
var autoMapperCollectionTypes = autoMapperCollectionAssembly.GetTypes();
var equalityComparisonGenericMethodInfo = autoMapperCollectionTypes
.Where(w => !w.IsGenericType && !w.IsNested)
.SelectMany(s => s.GetMethods()).Where(w => w.Name == "EqualityComparison")
.FirstOrDefault()
.MakeGenericMethod(type, targetType);
//Make the call to EqualityComparison
//Exemple configuration.CreateMap<Source, Target>().EqualityComparison((source, target) => source.Id == target.Id)
equalityComparisonGenericMethodInfo.Invoke(createMapResult, new object[] { createMapResult, expressionLambdaResult });
}
}
