Returning an array from JS to C# with COM-Interop

Question

I'm returning some data from my JavaScript code to my C# code via COM Interop and the WebBrowser WPF control. I have successfully returned the data which looks like this in Javascript:

var result = new Array(); 
result[0] = cbCamera.selectedItem; 
result[1] = cbMicrophone.selectedItem;

Now I have the object result in C# which looks like this:

result.GetType(); 
{Name = "__ComObject" FullName = "System.__ComObject"}

How can I get the javascript strings contained in this array which is in this ComObject?

Answer 1

1. Silly question, but have you tried casting the object into string[]?
2. Did you try casting into IEnumerator, or do a foreach string on it?

Answer 2

To find the underlaying type of the object contained in the rutime callable wrapper (System.__ComObject) you would use refection. You would then be able to create or cast to a managed type from this information.

For example;

string type = (string)result.GetType().InvokeMember("getType",
BindingFlags.InvokeMethod, null, result, null);

Alternatively you could use invokeMember to retrieve the values. For example you could invoke the valueOf method to convert the array to the most meaningful primitive values possible or toString to covert the array to a csv string.

string result = (string)result.GetType().InvokeMember("toString",
BindingFlags.InvokeMethod, null, result, null);
string[] jsArray = result.Split(',');
// c# jsArray[n] = js result[n] 

EDIT: A third way to do this in c# 4.0 is to use the new dynamic type. The dynamic type makes it really easy to make late-bound calls on COM objects.

string csv = ((dynamic)result).toString();