Question

I have a number of extension methods defined in my current project. It is a VB.NET project. I have no problem using these methods inside files that are in the App_Code directory, this is the same place that I defined the methods. However, in my page.aspx.vb code behind page these methods are not showing up. I have tried including the correct namespace, with no luck.

Does anyone have an idea as to why I can’t call an extension method in a code behind file?

Defined in the App_Code folder

<Extension()> _ Public Function GetSelected(ByVal apps As List(Of Appointment)) As Appointment     Dim selected = From a In apps _                    Where a.Selected = True      Return selected.Single End Function 

Defined in the App_Code folder, inside another class(this one works just fine)

Public ReadOnly Property Selected() As Appointment     Get         Return _appointments.GetSelected()     End Get End Property 

Defined in the App Root folder, inside a code behind file(Not working)

Public ReadOnly Property Selected() As Appointment     Get         Return _appointments.GetSelected()     End Get End Property 

They are all in the same application, no external references. And When I build the project there are no errors, until I try to use the extension method in the code behind. At that point the error is ‘GetSelected’ is not a member of ‘System.Collections.Generic.List(Of Appointment)’

Answer 1

Make sure your module is marked Public.