如果测试对象是在C＃字典 [英] Testing if an Object is a Dictionary in C#

问题描述

有没有一种方法来测试一个对象是否是一个字典？

Is there a way to test if an object is a dictionary?

在一个方法我试图在列表框中从选定项目得到的值。在某些情况下，列表框可​​能被绑定到一个字典，但这不是在编译时已知

In a method I'm trying to get a value from a selected item in a list box. In some circumstances, the list box might be bound to a dictionary, but this isn't known at compile time.

我愿做类似这样：

if (listBox.ItemsSource is Dictionary<??>)
{
    KeyValuePair<??> pair = (KeyValuePair<??>)listBox.SelectedItem;
    object value = pair.Value;
}

有没有办法在运行时使用反射动态地做到这一点？我知道这是可能使用反射与泛型类型，并确定键/值的参数，但我不知道是否有一种方法做检索这些值后，其余部分。

Is there a way to do this dynamically at runtime using reflection? I know it's possible to use reflection with generic types and determine the key/value parameters, but I'm not sure if there's a way to do the rest after those values are retrieved.

推荐答案

这应该是像下面这样。我写这个的答案框，以便语法可能不完全正确的，但我做了它的wiki编辑的所以任何人都可以解决了。

It should be something like the following. I wrote this in the answer box so the syntax may not be exactly right, but I've made it Wiki editable so anybody can fix up.

if (listBox.ItemsSource.IsGenericType && 
    typeof(IDictionary<,>).IsAssignableFrom(listBox.ItemsSource.GetGenericTypeDefinition()))
{
    var method = typeof(KeyValuePair<,>).GetProperty("Value").GetGetMethod();
    var item = method.Invoke(listBox.SelectedItem, null);
}

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