Pass Text From a List View Controller to a OnClick Sub VB.Net - asp.net

Question

Is there a way to pass text from a List View controller to a OnClick Subroutine? For example, there's a label in the List View and I've attached a Button in the List View and attached an OnClick Subroutine to it. Now I want to pass the text from the Label over to the OnClick Subroutine. I hope this make sense. Down below is my code:
VB.Net Code:
Protected Sub AmButtonClick(ByVal sender As Object, ByVal e As System.EventArgs)
Dim url As String = CType(Me.AmListViewDetails.FindControl("merchantLink"), Label).Text
Dim sb As New StringBuilder()
sb.Append("<script type = 'text/javascript'>"_
sb.Append("window.open('")
sb.Append(url)
sb.Append("');")
sb.Append("</script>")
ClientScript.RegisterStartupScript(Me.GetType(), "script", sb.ToString())
End Sub
ASP.Net:
<asp:ListView runtat="server" ID="AmListViewDetails" ...>
<ItemTemplate>
<table runat="server">
<tr runat="server">
<td runat="server">
<asp:Label ID="merchantLink" runat="server" Text='<%Eval("Link")%>' />
</td>
</tr>
<tr runat="server">
<td runat="server">
<asp:Button ID="AmBtn" runat="server" Text="Checkout" OnClick="AmButtonClick"/>
</td>
</tr>
</table>
</ItemTemplate>
</asp:ListView>

Answer 1

Add a CommandArgument property to the button. That's going to be the value passed to the event handler. You don't need an OnClick property.
<asp:Button ID="AmBtn" runat="server" Text="Checkout" CommandArgument="???" />
Your event handler would be
Sub AmListViewDetails_ItemCommand(object sender, ListViewCommandEventArgs e)
Dim valuePassedFromListView = Cstr(e.CommandArgument)
End Sub