我想通過指定點(diǎn)分隔路徑來更新任何公共屬性中的值。但是每當(dāng)我調(diào)用我的方法時(shí)，我都會(huì)收到一條錯(cuò)誤消息：pi.SetValue(instance, value1, null);錯(cuò)誤信息：對(duì)象與目標(biāo)類型不匹配。我的方法：private void SetPathValue(object instance, string path, object value){ string[] pp = path.Split('.'); Type t = instance.GetType(); for (int i = 0; i < pp.Length; i++) { PropertyInfo pi = t.GetProperty(pp[i]); if (pi == null) { throw new ArgumentException("Properties path is not correct"); } else { instance = pi.GetValue(instance, null); t = pi.PropertyType; if (i == pp.Length - 1)//last { // Type targetType = IsNullableType(pi.PropertyType) ? Nullable.GetUnderlyingType(pi.PropertyType) : pi.PropertyType; var value1 = Convert.ChangeType(value, instance.GetType()); pi.SetValue(instance, value1, null);//ERROR } } }}private static bool IsNullableType(Type type){ return type.IsGenericType && type.GetGenericTypeDefinition().Equals(typeof(Nullable<>));}
2 回答
慕蓋茨4494581
TA貢獻(xiàn)1850條經(jīng)驗(yàn) 獲得超11個(gè)贊
我認(rèn)為您的原始版本最終會(huì)將值設(shè)置為“太深一層”。
我認(rèn)為遞歸模式更容易遵循，并且需要更少的代碼。這是我整理的一個(gè)快速版本，適用于簡(jiǎn)單的測(cè)試用例。
有幾個(gè)優(yōu)化機(jī)會(huì)（在遞歸調(diào)用中重建字符串）和邊緣情況（如null檢查），我現(xiàn)在沒有時(shí)間處理，但我認(rèn)為它們不會(huì)太難添加。
public void SetProperty(object target, string property, object setTo)
{
var parts = property.Split('.');
var prop = target.GetType().GetProperty(parts[0]);
if (parts.Length == 1)
{
// last property
prop.SetValue(target, setTo, null);
}
else
{
// Not at the end, go recursive
var value = prop.GetValue(target);
SetProperty(value, string.Join(".", parts.Skip(1)), setTo);
}
}
這是一個(gè) LINQPad 演示，展示了它的實(shí)際效果：
void Main()
{
var value = new A();
Debug.WriteLine("Original value:");
value.Dump();
Debug.WriteLine("Changed value:");
SetProperty(value, "B.C.D","changed!");
value.Dump();
}
public void SetProperty(object target, string property, object setTo)
{...}
public class A
{
public B B { get; set; } = new B();
}
public class B
{
public C C { get; set; } = new C();
}
public class C
{
public string D { get; set; } = "test";
}
它產(chǎn)生以下結(jié)果：
手掌心
TA貢獻(xiàn)1942條經(jīng)驗(yàn) 獲得超3個(gè)贊
我想完成答案Bradley Uffner
public void SetProperty (object target, string property, object setTo)
{
var parts = property.Split ('.');
// if target object is List and target object no end target -
// we need cast to IList and get value by index
if (target.GetType ().Namespace == "System.Collections.Generic"
&& parts.Length != 1)
{
var targetList = (IList) target;
var value = targetList[int.Parse (parts.First ())];
SetProperty (value, string.Join (".", parts.Skip (1)), setTo);
}
else
{
var prop = target.GetType ().GetProperty (parts[0]);
if (parts.Length == 1)
{
// last property
prop.SetValue (target, setTo, null);
}
else
{
// Not at the end, go recursive
var value = prop.GetValue (target);
SetProperty (value, string.Join (".", parts.Skip (1)), setTo);
}
}
}
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