My Example contains a gridview containing a boundfield and a template field

<asp:GridView ID="gvEmail" runat="server" SkinID="DefaultGVWithoutPaging" >
<Columns>
<asp:BoundField HeaderText="Title" DataField="Title" />
<asp:TemplateField>
<ItemTemplate>
<asp:ImageButton ID="ibtnEdit" SkinID="EditButtonImageSkin" CommandName="EditEmails" CommandArgument='<%#Container.DataItem("FileName") & ";" & Container.DataItem("Keywords") %>' runat="server" />
</ItemTemplate>
</asp:TemplateField>
</Columns>
</asp:GridView>

And on Server side use the split operator to split, i use the ‘;’ character as splitter

Protected Sub gvEmail_RowCommand(ByVal sender As Object, ByVal e As System.Web.UI.WebControls.GridViewCommandEventArgs) Handles gvEmail.RowCommand
If e.CommandName = "EditEmails" Then

Dim paraArray() As String
paraArray = e.CommandArgument.ToString.Split(CChar(";"))

End If
End Sub

Hope to help someone.