反射 - 如何获取参数指定索引处的值
我正在尝试使用反射获取属性的指定索引的值。
此答案适用于List<> 类型的标准属性例如，但在我的例子中，我尝试使用的集合具有不同的格式：
public class NumberCollection : List<int>
{
public NumberCollection()
{
nums = new List<int>();
nums.Add(10);
}
public new int this[int i]
{
get { return (int) nums[i]; }
}
private List<int> nums;
}
public class TestClass
{
public NumberCollection Values { get; private set; }
public TestClass()
{
Values = new NumberCollection();
Values.Add(23);
}
}
class Program
{
static void Main(string[] args)
{
TestClass tc = new TestClass();
PropertyInfo pi1 = tc.GetType().GetProperty("Values");
Object collection = pi1.GetValue(tc, null);
// note that there's no checking here that the object really
// is a collection and thus really has the attribute
String indexerName = ((DefaultMemberAttribute)collection.GetType()
.GetCustomAttributes(typeof(DefaultMemberAttribute),
true)[0]).MemberName;
// Code will ERROR on the next line...
PropertyInfo pi2 = collection.GetType().GetProperty(indexerName);
Object value = pi2.GetValue(collection, new Object[] { 0 });
Console.Out.WriteLine("tc.Values[0]: " + value);
Console.In.ReadLine();
}
}
此代码给出 AmbigouslyMatchException（“发现不明确的匹配。”）。我知道我的收藏类有点做作，但有人可以帮忙吗？
I'm trying to get the value of a specified index of a property using reflection.
This answer works for standard properties that are of type List<> for example, but in my case, the collection I am trying to work with is of a different format:
public class NumberCollection : List<int>
{
public NumberCollection()
{
nums = new List<int>();
nums.Add(10);
}
public new int this[int i]
{
get { return (int) nums[i]; }
}
private List<int> nums;
}
public class TestClass
{
public NumberCollection Values { get; private set; }
public TestClass()
{
Values = new NumberCollection();
Values.Add(23);
}
}
class Program
{
static void Main(string[] args)
{
TestClass tc = new TestClass();
PropertyInfo pi1 = tc.GetType().GetProperty("Values");
Object collection = pi1.GetValue(tc, null);
// note that there's no checking here that the object really
// is a collection and thus really has the attribute
String indexerName = ((DefaultMemberAttribute)collection.GetType()
.GetCustomAttributes(typeof(DefaultMemberAttribute),
true)[0]).MemberName;
// Code will ERROR on the next line...
PropertyInfo pi2 = collection.GetType().GetProperty(indexerName);
Object value = pi2.GetValue(collection, new Object[] { 0 });
Console.Out.WriteLine("tc.Values[0]: " + value);
Console.In.ReadLine();
}
}
This code gives an AmbiguousMatchException ("Ambiguous match found."). I know my collection class is somewhat contrived, but can anyone help with this?
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评论（2）
一种选择是根据需要
将
Collection.GetType()更改为另一种类型。但基本上：循环属性而不是使用 Type.GetProperty 。One option is to use
Change
Collection.GetType()to another type if you want. But basically: loop over the properties instead of usingType.GetProperty.如果您要查找所有默认成员，可以询问 Type.GetDefaultMembers()，然后检查成员以找到您要查找的成员。
或者，如果您知道索引器的数据类型，则可以调用 GetPropertyInfo 与类型数组说明符。
If you are looking for all of the default members, you can ask for Type.GetDefaultMembers(), then examine the members to find the one that you are looking for.
Alternatively, if you know the data type of the indexer, you can call GetPropertyInfo with the type array specifier.