C# 您如何仅找到同时具有 getter 和 setter 的属性？

How do you find only properties that have both a getter and setter?

提问by Matt

C#, .NET 3.5

C#、.NET 3.5

I am trying to get all of the properties of an object that have BOTH a getter and a setter for the instance. The code I thoughtshould work is

我正在尝试获取一个对象的所有属性，这些属性同时具有实例的 getter 和 setter。我认为应该工作的代码是

PropertyInfo[] infos = source.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.GetProperty);

However, the results include a property that does not have a setter. To give you a simple idea of my inheritance structure that might be affecting this (though I don't know how):

但是，结果包括一个没有 setter 的属性。为了让您对我的可能会影响此的继承结构有一个简单的了解（尽管我不知道如何）：

public interface IModel
{
    string Name { get; }
}

public class BaseModel<TType> : IModel
{
    public virtual string Name { get { return "Foo"; } }

    public void ReflectionCopyTo(TType target)
    {
        PropertyInfo[] infos = this.GetType().GetProperties(BindingFlags.Instance | BindingFlags.Public | BindingFlags.SetProperty | BindingFlags.GetProperty);
        foreach (PropertyInfo info in infos)
            info.SetValue(target, info.GetValue(this, null), null);
    }
}

public class Child : BaseModel<Child>
{
    // I do nothing to override the Name property here
}

I end up with the following error when working with Name:

使用 Name 时，我最终遇到以下错误：

System.ArgumentException: Property set method not found.

EDIT: I would like to know why this does notwork, as well as what I should be doing to not get the error.

编辑：我想知道为什么这样做没有工作，还有什么我应该怎样做才能不出现错误。

采纳答案by Jon Skeet

Call GetGetMethodand GetSetMethodon the property - if both results are non-null, you're there :)

调用GetGetMethod和GetSetMethod属性 - 如果两个结果都不为空，你就在那里:)

(The parameterless versions only return public methods; there's an overload with a boolean parameter to specify whether or not you also want non-public methods.)

（无参数版本只返回公共方法；有一个带有布尔参数的重载来指定您是否还需要非公共方法。）

回答by Jon Skeet

This isn't supposed to work.

这不应该工作。

See definition of GetPropertieson msdnfor which is allowed:

见的定义GetProperties在MSDN对允许：

The following BindingFlagsfilter flags can be used to define which nested types to include in the search:

以下BindingFlags过滤器标志可用于定义要包含在搜索中的嵌套类型：

* You must specify either BindingFlags.Instance or BindingFlags.Static in order to get a return.
* Specify BindingFlags.Public to include public properties in the search.
* Specify BindingFlags.NonPublic to include non-public properties (that is, private and protected members) in the search.
* Specify BindingFlags.FlattenHierarchy to include static properties up the hierarchy.

Or you can see the definition of GetProperty/SetPropertyin msdn, which states that:

或者您可以在msdn 中看到GetProperty/的定义，其中指出：SetProperty

GetProperty = Specifies that the value of the specified property should be returned.

SetProperty = Specifies that the value of the specified property should be set. For COM properties, specifying this binding flag is equivalent to specifying PutDispProperty and PutRefDispProperty.

GetProperty = 指定应返回指定属性的值。

SetProperty = 指定应设置指定属性的值。对于 COM 属性，指定此绑定标志等效于指定 PutDispProperty 和 PutRefDispProperty。

回答by Tim Jarvis

how about...

怎么样...

var qry = typeof(Foo).GetProperties(BindingFlags.Instance | BindingFlags.Public)
            .Where(p => p.CanRead && p.CanWrite);

回答by Matthieu DUFOURNEAUD-RAVEL

You can check the PropertyInfo.CanReadand PropertyInfo.CanWriteproperties.

您可以检查PropertyInfo.CanRead和PropertyInfo.CanWrite属性。

回答by Herman Schoenfeld

To make it a little more generic you can inherit from 'ObjectWithDefaultValues' and/or call obj.SetDefaultValues() extension method. Both are listed below.

为了使它更通用一点，您可以从 'ObjectWithDefaultValues' 继承和/或调用 obj.SetDefaultValues() 扩展方法。下面列出了两者。

Code:

代码：

public abstract class ObjectWithDefaultValues : object {

    public ObjectWithDefaultValues () : this(true){
    }

    public ObjectWithDefaultValues (bool setDefaultValues) {
        if (setDefaultValues)
            this.SetDefaultValues();    
    }
}

public static class ObjectExtensions {

    public static void SetDefaultValues(this object obj) {
        foreach (FieldInfo f in obj.GetType().GetFields(BindingFlags.Instance | BindingFlags.FlattenHierarchy | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetField)) {
            foreach (Attribute attr in f.GetCustomAttributes(true)) {
                if (attr is DefaultValueAttribute) {
                    var dv = (DefaultValueAttribute)attr;
                    f.SetValue(obj, dv.Value);
                }
            }
        }

        foreach (var p in obj.GetType().GetProperties(BindingFlags.Instance | BindingFlags.FlattenHierarchy | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.SetProperty)) {
            if (p.GetIndexParameters().Length == 0) {
                foreach (Attribute attr in p.GetCustomAttributes(true)) {
                    if (attr is DefaultValueAttribute) {
                        var dv = (DefaultValueAttribute)attr;
                        p.SetValue(obj, dv.Value, null);
                    }
                }
            }
        }
    }
}