通过反射获取C＃中的扩展方法的泛型重载

Question

I have following extensions class:

public static class KeyValueConfigurationCollectionExtensions
{
    public static string Get(this KeyValueConfigurationCollection collection, string key)
    {
        return collection[key].Value;
    }
    public static T Get<T>(this KeyValueConfigurationCollection collection, string key)
    {
        return (T)Convert.ChangeType(collection[key].Value, typeof(T));
    }
}

Could someone tell me how can I get overload for generic method (the 2nd one from the above example) by reflection? There is AmbiguousMatchException thrown at runtime for this line of code:

MethodInfo method = typeof(KeyValueConfigurationCollectionExtensions).GetMethod("Get");

I know that there is an overload for GetMethod function where I can specify parameters but in that case those are the same for both methods. It would be great to solve that as I need it for my acceptance tests.

---

Update

The simplest solution for me was:

MethodInfo methodInfo = typeof(KeyValueConfigurationCollectionExtensions)
    .GetMethods().Single(method => method.Name == "Get" && method.IsGenericMethod);

Thanks guys for quick answers and wish you nice day :)

Answer 1

There´s also IsGenericMethod defined on MethodInfo :

MethodInfo method = typeof(KeyValueConfigurationCollectionExtensions).GetMethods()
    .FirstOrDefault(x => g.Name == "Get" && x.IsGenericMethod);

Answer 2

You need to get the method that has generic arguments by calling GetGenericArguments() , as in this example Linqpad:

void Main()
{
    var method = typeof(KeyValueConfigurationCollectionExtensions)
        .GetMethods()
        .Where(m => m.Name == "Get")
        .Where(m => m.GetGenericArguments().Any())
        .Single()
        .Dump();

}

// Define other methods and classes here
public static class KeyValueConfigurationCollectionExtensions
{
    public static string Get(this KeyValueConfigurationCollection collection, string key)
    {
        return collection[key].Value;
    }
    public static T Get<T>(this KeyValueConfigurationCollection collection, string key)
    {
        return (T)Convert.ChangeType(collection[key].Value, typeof(T));
    }
}

public class KeyValueConfigurationCollection
{
    public KeyValuePair<string, string> this [string key]
    {
        get
        {
            return new KeyValuePair<string, string>("KEY: " + key, "VALUE: Hi!");
        }
    }
}

Answer 3

如果您有重载的方法，则必须对linq使用GetMethods方法：

MethodInfo method = typeof(KeyValueConfigurationCollectionExtensions).GetMethods().FirstOrDefault(m=>m.Name=="Get"&&m.ContainsGenericParameters==true).MakeGenericMethod(new Type[]{yourtype});