Question

I’m trying to implement generating PDF using a library iTextSharp to an old project we have at the company, everything is working great, except for when adding the Imports to a form that is using RadioButtonList, it treats this RadioButtonList as an iTextSharp object not System.Web.UI.WebControls and gives me the following error

Overload resolution failed because no accessible ‘Add’ can be called with these arguments:

'Public Sub Add(item As System.Web.UI.WebControls.ListItem)': Value of type 'iTextSharp.text.ListItem' cannot be converted to 'System.Web.UI.WebControls.ListItem'.
'Public Sub Add(item As String)': Value of type 'iTextSharp.text.ListItem' cannot be converted to 'String'

This control is defined as follows :

<asp:RadioButtonList ID="rblChargeOrNot" runat="server" AutoPostBack="True" RepeatDirection="Horizontal" Width="60%"></asp:RadioButtonList>

and the same for

 <asp:DropDownList ID="ddlnumber" runat="server"></asp:DropDownList>

Tech in use is vb.net framework 3.5

Answer 1

No, it’s treating something that you’ve declared as ListItem as iTestSharp.text.ListItem rather than System.Web.UI.WebControls.ListItem.

You’ve not shown the code where you construct this ListItem object – but you need to either fully qualify the name, or consider changing your Imports for this class so that it won’t assume you mean iTextSharp.text.ListItem when you declare this object.

I.e. you probably have code that looks like this:

Import System
Import System.Web.UI
Import iTextSharp.text

...

Dim li as ListItem

Note that the iTextSharp.text namespace is imported, but System.Web.UI.WebControls isn’t. VB decides that the ListItem object belongs to iTextSharp.text. If you had imported System.Web.UI.WebControls, you’d get an error message on that declaration being ambiguous. You can fix it with:

Dim li as System.Web.UI.WebControls.ListItem