如何使用C＃反射获取对象属性？

要在C#中使用反射获取对象属性，首先调用GetType()方法获取类型信息，再使用GetProperties()获取属性数组。1. 使用prop.GetValue(obj)获取属性值并遍历输出可用于调试或序列化；2. 要访问非公共属性，需指定BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance；3. 可通过GetProperty("PropertyName")获取特定属性，或按类型、特性过滤属性；4. 处理索引器时检查GetIndexParameters()长度，并用try-catch包裹GetValue()防止异常；反射功能强大但性能较低，应谨慎使用。

To get object properties in C# using reflection, you typically use the GetType() method on the object, then call GetProperties() to retrieve an array of PropertyInfo objects. From there, you can access each property’s name, value, and other metadata.

Getting Started: Accessing All Public Properties

The most straightforward way to retrieve properties is by using GetProperties() on a type. This method returns all public properties of the object by default.

MyClass obj = new MyClass();
Type type = obj.GetType();
PropertyInfo[] properties = type.GetProperties();

Each PropertyInfo object contains information like the property name, type, and whether it has a getter or setter.

If you want to print out the names and values of all public properties:

foreach (var prop in properties)
{
    object value = prop.GetValue(obj);
    Console.WriteLine($"{prop.Name}: {value}");
}

This is useful for debugging, serialization, or dynamically inspecting an object’s structure.

Accessing Non-Public Properties

By default, GetProperties() only returns public members. If you need to access private or protected properties, you must specify BindingFlags.

Here’s how you can get all properties, including non-public ones:

PropertyInfo[] properties = type.GetProperties(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);

This can be handy when you're working with third-party libraries or sealed classes where you don’t have control over access modifiers.

Just keep in mind that accessing non-public members may be restricted in some environments (like partial trust scenarios), and it’s generally better to use public APIs when available.

Filtering or Working with Specific Properties

Sometimes you only need to work with a specific property, not all of them. You can use GetProperty() to get a single property by name:

PropertyInfo prop = type.GetProperty("PropertyName");
if (prop != null)
{
    object value = prop.GetValue(obj);
    Console.WriteLine(value);
}

You can also filter properties based on criteria like type or custom attributes. For example, if you want to get only string properties:

var stringProps = properties.Where(p => p.PropertyType == typeof(string));

This is useful in scenarios like model validation or data mapping, where you might want to process only certain types of properties.

Handling Indexers and Special Cases

Some classes have indexed properties (like Item in a collection), which show up in GetProperties(). You can identify them by checking the GetIndexParameters() method:

foreach (var prop in properties)
{
    if (prop.GetIndexParameters().Length > 0)
    {
        Console.WriteLine($"{prop.Name} is an indexer.");
    }
}

Also, be aware that some properties may throw exceptions when accessed via reflection — especially if they rely on internal state or require parameters.

In such cases, wrap the GetValue() call in a try-catch block:

try
{
    object value = prop.GetValue(obj);
}
catch (Exception ex)
{
    Console.WriteLine($"Error getting {prop.Name}: {ex.Message}");
}

This helps avoid runtime crashes when inspecting unknown or complex types.

基本上就这些。 Reflection is powerful but should be used carefully — especially in performance-sensitive code — since it's slower than direct property access.

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