How can I get an instance of a static class with a string?
Example:
class Apple : IFruit
{
public static Apple GetInstance() { ... }
private Apple() { }
// other stuff
}
class Banana : IFruit
{
public static Banana GetInstance() { ... }
private Banana() { }
// other stuff
}
// Elsewhere in the code...
string fruitIWant = "Apple";
IFruit myFruitInstance = [What goes here using "fruitIWant"?].GetInstance();
Type appleType = Type.GetType("Apple");
MethodInfo methodInfo = appleType.GetMethod(
"GetInstance",
BindingFlags.Public | BindingFlags.Static
);
object appleInstance = methodInfo.Invoke(null, null);
Note that in Type.GetType you need to use the assembly-qualified name.
Here is a complete example. Just pass in the name of the type you want to load and the name of the method to invoke:
namespace Test
{
class Program
{
const string format = @"hh\:mm\:ss\,fff";
static void Main(string[] args)
{
Console.WriteLine(Invoke("Test.Apple", "GetInstance"));
Console.WriteLine(Invoke("Test.Banana", "GetInstance"));
}
public static object Invoke(string type, string method)
{
Type t = Type.GetType(type);
object o = t.InvokeMember(method, BindingFlags.InvokeMethod, null, t, new object[0]);
return o;
}
}
class Apple
{
public static Apple GetInstance() { return new Apple(); }
private Apple() { }
// other stuff
}
class Banana
{
public static Banana GetInstance() { return new Banana(); }
private Banana() { }
// other stuff
}
}
You do like this:
string fruitIWant = "ApplicationName.Apple";
IFruit a = Type.GetType(fruitIWant).GetMethod("GetInstance").Invoke(null, null) as IFruit;
For ApplicationName you substitute the namespace where the class is declared.
(Tested and working.)
OK, may be I got your question. A pseudocode
EDIT
foreach (var type in System.Reflection.Assembly.GetExecutingAssembly().GetTypes())
{
if (type.Name.Equals("MyClass"))
{
MethodInfo mi = type.GetMethod("GetInstance", BindingFlags.Static);
object o = mi.Invoke(t, null);
break;
}
}
Should work..
typeof(Apple) but I need this to be figured out using a string. You can never type Apple by itself, you need to use the string variable. Additionally, this can be condensed into one line - no need to declare an additional MethodInfo that you'll never use.
While the others give you what you asked for, this is probably what you want:
IFriut GetFruit(string fruitName)
{
switch(fruitName)
{
case "Apple":
return Apple.GetInstance();
case "Banana":
return Banana.GetInstance();
default:
throw new ArgumentOutOfRangeException();
}
}
IFruit, which I don't want to do (and which defeats the purpose of having an interface in the first place), especially if I'm dynamically loading assemblies. This code's maintainability is very poor.