Unable to make value fields editable after clicking on a link button

Question

I've created a link button and made a event handler for it. But still unable to make the values editable.

This is the link button:

<FooterTemplate>
<asp:LinkButton ID="lbEdit" runat="server" OnClick="lbEdit_Click">Edit</asp:LinkButton>
</FooterTemplate>

Here is the code behind:

protected void lbEdit_Click(object sender, EventArgs e)
{
    dvEAEdit.DefaultMode = DetailsViewMode.Edit;
}

Any help is appreciated!