Get InstalledSources in vb2008

[riona26]

Hi there,

I followed the example post in Techincal Reference for InstalledSources. After i upgraded my project from VB6 to VB2008, i got the following error once VB process the code "devs = EZTwain.InstalledSources":

"Unable to cast object of type 'System.Object[*]' to type 'System.Object[]'."

i've tried to declare devs as 2 dimension array, but i still got similar error.

Please advice for solution.

Regards,
Riona

[riona26]

1 week past, any feedback?

[Spike]

Hi Riona - sorry for the long delay. I have to admit, I have no clue. Those don't even look like VB types, but then this is .NET. And I am not particularly fluent in VB.NET (slightly more in C#, but not much...)

Aha - I think maybe the problem is that InstalledSources returns a variant array with a lower-bound of 1, which is of course standard for VB. In .NET, there are no variants (System.Object plays that role, sort of), and all arrays are 0-indexed, so... MS in their collective wisdom decided this particular conversion shall not be done automatically.

How about something like this:

      Dim obj As Object() = EZTwain.InstalledSources()
      Dim strRet(obj.Length) As String

      Dim i As Integer
      For i = 0 To obj.Length - 1
         strRet(i) = Convert.ToString(obj(i+1))
      Next
      ' strRet now contains string array.

I'm not sure you even need that Convert.ToString.
Based on code by msdixon found on Experts Exchange:
http://www.experts-exchange.com/Prog..._20889243.html

[samb]

Not sure if Spikes solution worked, or if Riona found a different solution, but in case anyone else runs into this.

In C# just doing Object[] list = EZTwain.InstalledSources() will crash giving the exception that Riona reported, so I think Spike's suggestion will die on the first line.

I fought this problem for a few hours a month or so ago and never got anywhere. Finally today I got back to working on it, did a search on that exception message and found a solution that works in c#. Should be easily converted to vb.net, but I'm a bit rusty on that syntax.

Array sourceList = (Array)(EZTwainX.InstalledSources);
foreach (Object source in sourceList)
{
     MessageBox.Show((string)(source));
}

Basically instead of declaring it as an array of objects, you can just declare it as an Array without providing any element type.

[Edit]
Found out I still have a VB.Net IDE on my system, so here's the syntax:

Dim sourceList As Array
sourceList = EZTwainX.InstalledSources
Dim source as Object
For Each source In sourceList
     MsgBox(source.ToString())
Next

[/Edit]