Retrieve string array from COM object using Classic ASP

I have a .NET class which holds a simple array of strings avail开发者_如何学Goable via an accessor method, which looks like this;

namespace Foo.Bar {
    [ComVisible(true)]
    [Guid("642279A0-85D4-4c7a-AEF5-A9FAA4BE85E5")]
    public class MyClass {
        private string[] _myArray;
        public MyClass() { }

        public MyClass(string[] myArray) {
            _myArray = myArray;
        }

        public string[] MyArray {
            get { return _myArray; }
        }
    }
}

I consume this class using Classic ASP;

Dim foo 
Set foo = Server.CreateObject("Foo.Bar.MyClass")

if IsArray(foo.MyArray) then Response.Write("IsArray") & "<br />"
Response.Write(typename(foo.MyArray)) & "<br />"
Response.Write(UBound(foo.MyArray)) & "<br />"

This results in;

IsArray
String()
1

However, when I try to access the contents of the array using;

Response.Write(foo.MyArray(0)) & "<br />"

I get;

Microsoft VBScript runtime (0x800A01C2) Wrong number of arguments or invalid property assignment: 'MyArray'

Any help is much appreciated.

Edit This is to provide more information after digesting the answers given (thanks)

When changing the implementation of the MyArray property to;

public object[] MyArray {
    get { return (object[])_myArray; }
}

I then get the following error,

Microsoft VBScript runtime (0x800A000D) Type mismatch: 'MyArray'

So I tried individually casting each string to an object;

public object[] MyArray {
    get {
        object[] tmp = new object[_myArray.Count()];
        for (int x = 0; x < _myArray.Count(); x++) {
            tmp[x] = (object)_myArray[x];
        }
        return tmp;
    }
}

Then I'm back to,

Microsoft VBScript runtime (0x800A01C2) Wrong number of arguments or invalid property assignment: 'MyArray'

Edit Final solution with help from How to correctly marshal VB-Script arrays to and from a COM component written in C#

C#

public object MyArray {
    get { return _myArray.Cast<object>().ToArray(); }
}

VBScript

Dim foo 
Set foo = Server.CreateObject("Foo.Bar.MyClass")

bar = foo.MyArray
Response.Write bar(0)

The key was to expose object rather than object[] and as AnthonyWJones suggested, assign the array to a variable before using it.

Thanks again.

---

The problem is VBScript cannot actually use an array of String. It can only use an array of Variant.

Try changing MyClass to expose an object[] instead.

---

In addition to Anthony's suggestion

I'm not sure is it the best way but in the past I used a code similar to the following to handle one dimensional arrays.

public object MyArray(int ix = -1){
    string[] tmp = new string[] {"one", "two", "3", "4"};
    return (ix == -1) ? (object)tmp : tmp[ix];
}

In ASP:

Response.Write(TypeName(foo.MyArray)) 'string()
Response.Write(TypeName(foo.MyArray(0))) 'string

---

VBScript doesn't understand generic collections such as List<string> and it doesn't understand string arrays either.

I wrote a public function into my Interface class to convert any generic collections into an ArrayList

public ArrayList toArrayList(IEnumerable collection)
{
        var arrayList = new ArrayList();
        foreach (object element in collection)
        {
            arrayList.Add(element);
        }
        return arrayList;
}

This code can then be used in VBScript like this

 dim connector
 set connector = model.getRelationByID(connectorID)
 'get the related elements
 dim relatedElements
 set relatedElements = model.toArrayList(connector.relatedElements)
 addRelatedElementoAutoDiagram relatedElements(0), relatedElements(1), model

The advantage of this approach is that I don't need to change the signature of any of the methods or properties in C#, but I can still use them in VBScript

---

This code demonstrates how to handle arrays between COM and ASP:

<% @Language="VBScript" %>
<% Option Explicit %>
<%
Dim tcs
Dim rc
Dim vntInput(0,4)
Dim i

vntInput(0,0) = Request.QueryString("strUser")
vntInput(0,1) = Request.QueryString("intCreate")
vntInput(0,2) = Request.QueryString("intDelete")
vntInput(0,3) = Request.QueryString("intModify")
vntInput(0,4) = Request.QueryString("intView") 

Set tcs = Server.CreateObject("TestCases.ArrayFailure")
rc = tcs.AcceptArray(vntInput)

For i = 0 to UBound(vntInput, 2)
    Response.write "Loop Count " & i & " " & vntInput(0,i) & "<BR>"
Next

%>

Here's a link to the article where I found this code:
http://202.102.233.250/b2000/ASP/articles/component/pv990826.htm