Tevin says:
<asp:LinkButton ID=
"lnkUpdate"
Text=
"Remove"
CausesValidation=
"false"
runat=
"server"
OnClick=
"lnkUpdate_Click"
CommandName=
"DeleteRow"
CommandArgument=
Use font-awesome. Replace above with below.
<asp:LinkButton ID="lnkUpdate" CausesValidation="false" runat="server" OnClick="lnkUpdate_Click"
CommandName="DeleteRow" CommandArgument='<%# Container.ItemIndex %>' ToolTip="remove record">
<span class="glyphicon glyphicon-trash"></span>
</asp:LinkButton>
Note: Add the font-awesome library in the page.
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />