Question

I’m currently writing a HMI for an automated machine in VB.Net 2010. I have a custom class that turns a Border green or red depending on the value of an input on a remote I/O module.

The connection to the remote I/O module is through a COM object provided by the manufacturer. I have three remote connections, lets’ call them g1, g2, and g3. They’re of type Manufacturer.ConnectionObject.

I would like to specify, using a property that I can set in XAML, that instances of MyCustomBorder use g1, g2, or g3. Unfortunately, setting up a Property called g and typing ‘g1’ into the property field results in the message “Property value is not valid. Details: Property ‘g’ does not support String to Value conversion.”

So, instead, I am left to manually set (during program startup), every single instance of MyCustomBorder:

CustomBorder1.g = g1
CustomBorder2.g = g3
CustomBorder73.g = g1

… and so on.

I am told I need to implement a converter between String and the custom class, Manufacturer.ConnectionObject, but I have no idea how to accomplish this, especially since Manufacturer.ConnectionObject is part of a closed-to-me COM object.

Help, anyone? Thanks!

Answer 1

Trying to directly bind a COM object into WPF is likely just going to cause you a lot of headaches. As a first step I would define a WPF friendly class which wraps instances of Manufacturer.ConnectionObject and bind that instead to WPF

Class MyConnectionObject 
  Public Manufacturer.ConnectionObject _connection

  Public Property Value As String 
    Get
      ' Return _connection as a String
    End Get
  End Property
End Class