在F＃中使用System.Reflection分配属性值

Question

我在C＃中具有以下代码行：

internal static object AssignMatchingPropertyValues(object sourceObject, object targetObject)
{
    Type sourceType = sourceObject.GetType();
    PropertyInfo[] sourcePropertyInfos = sourceType.GetProperties(BindingFlags.Public | BindingFlags.Instance);
    foreach (var sourcePropertyInfo in sourcePropertyInfos)
    {
        var targetPropertyInfo = targetObject.GetType().GetProperty(sourcePropertyInfo.Name);
        if (targetPropertyInfo != null)
        {
            targetPropertyInfo.SetValue(targetObject, sourcePropertyInfo.GetValue(sourceObject, null), null);
        }
    }
    return targetObject;
}

我想在F＃中实现等效功能，因此我做了如下操作：

member this.AssignMatchingPropertyValues(sourceObject, targetObject)=
    let sourceType = sourceObject.GetType()
    let sourcePropertyInfos = sourceType.GetProperties(BindingFlags.Instance)
    let assignedProperities = sourcePropertyInfos 
                                |> Seq.map(fun spi -> spi, targetObject.GetType().GetProperty(spi.Name))
                                |> Seq.map(fun (spi,tpi) -> tpi.SetValue(targetObject, spi.GetValue(sourceObject,null),null))        
    ()

问题是它不起作用。我认为不变性是永恒的，我正在得到一个新系列。有没有办法引用原始收藏？这是解决这个问题的正确途径吗？

Answer 1

Seq.map很懒，您没有在任何地方进行评估。您可以使用Seq.iter：

sourcePropertyInfos 
    |> Seq.map(fun spi -> spi, targetObject.GetType().GetProperty(spi.Name))
    |> Seq.iter(fun (spi,tpi) -> tpi.SetValue(targetObject, spi.GetValue(sourceObject,null),null))

Answer 2

这是C＃的直接翻译，而不是F＃代码：

let AssignMatchingPropertyValues sourceObject targetObject =
    let sourceType = sourceObject.GetType()
    let targetType = targetObject.GetType()
    let sourcePropertyInfos = sourceType.GetProperties(BindingFlags.Public ||| BindingFlags.Instance)
    for sourcePropertyInfo in sourcePropertyInfos do
        match targetType.GetProperty(sourcePropertyInfo.Name) with
        | null -> ()
        | targetPropertyInfo -> targetPropertyInfo.SetValue(targetObject, sourcePropertyInfo.GetValue(sourceObject, null), null)
    targetObject