I need to assign a value via PropertyInfo.
I'm having some problems when the type of the property is my custom class (a wrapper around a dictionary, designed to contain multiple language versions of the same text).
It looks like that:
public class MultilingualString
{ 开发者_如何学Python
Dictionary<string, string> Versions;
public string this[string languageCode]
{
get
{
if (Versions.Keys.Contains(languageCode))
{
return Versions[languageCode];
}
return null;
}
set
{
if (Versions.Keys.Contains(languageCode))
{
Versions[languageCode] = value;
}
else
{
Versions.Add(languageCode, value);
}
}
// [blah blah other stuff...]
}
So; now I have this PropertyInfo object - and a string value I would like to assign with a default language code.
certainPropertyInfo.SetValue(
instance, // an instance of some class exposing a MultilingualString type property
someString,
new[] { "eng" }); // some default language code
This throws an exception.
I guess the last argument of SetValue is meant to be a collection index and it doesn't work with a custom indexer.
Effectively what I'm trying to do is, obviously:
instance.msProperty["eng"] = someString;
But I am only given the name of msProperty, that's why I'm using reflection.
So far I have thought about implementing an implicit operator (within the MultilingualString class), allowing to convert string values to MultilingualString... but I can see some problems with that approach eg. this static operator would hardly have a way of "knowing" what the default language code is.
Can I achieve my goal via reflection?
The indexer is a property of its own. You need to get the indexer property of the instance in that certain property of yours:
var multilingualString = certainPropertyInfo.GetValue(instance, null);
multilingualString.GetType().GetProperty("Item").SetValue(multilingualString,
someString,
new object[]{ "eng" });
Item
is the default name for the indexer property.
If you are using .NET 4.0, you can use the new dynamic
type:
dynamic multilingualString = certainPropertyInfo.GetValue(instance, null);
multilingualString["eng"] = someString;
精彩评论