CODEWITHSUNDEEP
c#
Foo
Foo

Reputation: 4596

What is the purpose of passing in a type into the TypeDescriptor.GetConverter method?

In the code below, although I am getting a typeconverter for type Person, but I could also use it for the type Dog. (The types Person and Dog have nothing to do with each other.)

    var person = new Person {Name = "Foo", Age = 99, Ssn = Guid.NewGuid()}; 
    TypeConverter converter = TypeDescriptor.GetConverter(typeof (Person));
    string str = converter.ConvertToInvariantString(new Dog());
    Console.WriteLine(str);//ConsoleApplication1.Dog

So what is the purpose of passing in a type int the GetConverter method?

Upvotes: 0

Views: 154

Answers (1)

keenthinker
keenthinker

Reputation: 7830

The TypeDescriptor.GetConverter(Type type) overload gives more options to the developer. MSDN states:

Call this version of this method only when you do not have an instance of the object.

So you should use the TypeDescriptor.GetConverter(Object o) whenever possible.

Scott Hanselmann has a good example in his blog article TypeConverters - he uses this method for a generic type identification:

public static T GetTfromString<T>(string mystring)
{
   var foo = TypeDescriptor.GetConverter(typeof(T));
   return (T)(foo.ConvertFromInvariantString(mystring));
}

The overload using Object as parameter will not work with scalar data types.

UPDATE

It will work, but you have to write one line more :-P (and add a restriction):

public static T GetTfromString<T>(string mystring) where T : new()
{
    var o = new T();
    var foo = TypeDescriptor.GetConverter(o);
    return (T)(foo.ConvertFromInvariantString(mystring));
}

GetTfromString<double>("10.5").Dump();

Upvotes: 1

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