鉴于这个班
class Foo
{
// Want to find _bar with reflection
[SomeAttribute]
private string _bar;
public string BigBar
{
get { return this._bar; }
}
}我想找到要用属性标记的私人物品_bar。那可能吗？
我已经在寻找属性的属性中做到了这一点，但是从来没有一个私有成员字段。
我需要设置哪些绑定标志才能获取私有字段？
Answers:
使用BindingFlags.NonPublic和BindingFlags.Instance标志
FieldInfo[] fields = myType.GetFields(
BindingFlags.NonPublic |
BindingFlags.Instance);使用反射获取私有变量的值：
var _barVariable = typeof(Foo).GetField("_bar", BindingFlags.NonPublic | BindingFlags.Instance).GetValue(objectForFooClass);使用反射设置私有变量的值：
typeof(Foo).GetField("_bar", BindingFlags.NonPublic | BindingFlags.Instance).SetValue(objectForFoocClass, "newValue");其中objectForFooClass是类类型Foo的非null实例。
GetInstanceField(typeof(YourClass), instance, "someString") as string 如何在C＃中获取私有字段的值？
在考虑私有成员时，需要注意的一件事是，如果您的应用程序以中等信任度运行（例如，当您在共享托管环境中运行时），它将找不到它们- BindingFlags.NonPublic选项将被忽略。
typeof(MyType).GetField("fieldName", BindingFlags.NonPublic | BindingFlags.Instance)您可以使用以下代码访问任意类型的任何私有字段：
Foo foo = new Foo();
string c = foo.GetFieldValue<string>("_bar");为此，您需要定义一个扩展方法来为您完成工作：
public static class ReflectionExtensions {
public static T GetFieldValue<T>(this object obj, string name) {
// Set the flags so that private and public fields from instances will be found
var bindingFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance;
var field = obj.GetType().GetField(name, bindingFlags);
return (T)field?.GetValue(obj);
}
}我个人使用这种方法
if (typeof(Foo).GetFields(BindingFlags.NonPublic | BindingFlags.Instance).Any(c => c.GetCustomAttributes(typeof(SomeAttribute), false).Any()))
{
// do stuff
}这是一些用于简单获取和设置私有字段和属性（带有setter的属性）的扩展方法：
用法示例：
public class Foo { private int Bar = 5; } var targetObject = new Foo(); var barValue = targetObject.GetMemberValue("Bar");//Result is 5 targetObject.SetMemberValue("Bar", 10);//Sets Bar to 10
码：
/// <summary>
/// Extensions methos for using reflection to get / set member values
/// </summary>
public static class ReflectionExtensions
{
/// <summary>
/// Gets the public or private member using reflection.
/// </summary>
/// <param name="obj">The source target.</param>
/// <param name="memberName">Name of the field or property.</param>
/// <returns>the value of member</returns>
public static object GetMemberValue(this object obj, string memberName)
{
var memInf = GetMemberInfo(obj, memberName);
if (memInf == null)
throw new System.Exception("memberName");
if (memInf is System.Reflection.PropertyInfo)
return memInf.As<System.Reflection.PropertyInfo>().GetValue(obj, null);
if (memInf is System.Reflection.FieldInfo)
return memInf.As<System.Reflection.FieldInfo>().GetValue(obj);
throw new System.Exception();
}
/// <summary>
/// Gets the public or private member using reflection.
/// </summary>
/// <param name="obj">The target object.</param>
/// <param name="memberName">Name of the field or property.</param>
/// <returns>Old Value</returns>
public static object SetMemberValue(this object obj, string memberName, object newValue)
{
var memInf = GetMemberInfo(obj, memberName);
if (memInf == null)
throw new System.Exception("memberName");
var oldValue = obj.GetMemberValue(memberName);
if (memInf is System.Reflection.PropertyInfo)
memInf.As<System.Reflection.PropertyInfo>().SetValue(obj, newValue, null);
else if (memInf is System.Reflection.FieldInfo)
memInf.As<System.Reflection.FieldInfo>().SetValue(obj, newValue);
else
throw new System.Exception();
return oldValue;
}
/// <summary>
/// Gets the member info
/// </summary>
/// <param name="obj">source object</param>
/// <param name="memberName">name of member</param>
/// <returns>instanse of MemberInfo corresponsing to member</returns>
private static System.Reflection.MemberInfo GetMemberInfo(object obj, string memberName)
{
var prps = new System.Collections.Generic.List<System.Reflection.PropertyInfo>();
prps.Add(obj.GetType().GetProperty(memberName,
System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance |
System.Reflection.BindingFlags.FlattenHierarchy));
prps = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where( prps,i => !ReferenceEquals(i, null)));
if (prps.Count != 0)
return prps[0];
var flds = new System.Collections.Generic.List<System.Reflection.FieldInfo>();
flds.Add(obj.GetType().GetField(memberName,
System.Reflection.BindingFlags.NonPublic | System.Reflection.BindingFlags.Instance |
System.Reflection.BindingFlags.FlattenHierarchy));
//to add more types of properties
flds = System.Linq.Enumerable.ToList(System.Linq.Enumerable.Where(flds, i => !ReferenceEquals(i, null)));
if (flds.Count != 0)
return flds[0];
return null;
}
[System.Diagnostics.DebuggerHidden]
private static T As<T>(this object obj)
{
return (T)obj;
}
}