Hi
I think you have to do the convert the parameter from object to string.
So your code need to be altered as below
<asp:GridView ID="gvSpecialist" runat="server" AutoGenerateColumns="false" Width="965px"
onpageindexchanging="gvSpecialist_PageIndexChanging" >
<columns>
<asp:TemplateField HeaderText="Doctor Name">
<itemtemplate>
<asp:LinkButton ID="lnkNames" runat="server" ForeColor="black" Text='<%#Eval("Name")%>' CommandName="Name" CommandArgument='<%# Eval("Name") %>'>
</itemtemplate>
<itemstyle width="250px" cssclass="gridcol" />
<HeaderStyle HorizontalAlign="Center" />
<asp:TemplateField >
<itemtemplate>
<asp:Image ID="Image1" runat="server" ImageUrl='<%# BindImage(Eval("online").ToString()) %>' ImageAlign="Left" />
</itemtemplate>
</columns>
<footerstyle backcolor="#D4A97F" font-bold="True" forecolor="White" />
<pagerstyle backcolor="#D4A97F" forecolor="Black" horizontalalign="Center">
Wrap="False" Font-Bold="True" />
I hope this one will help you