Como chamar uma tela pop-up a partir de um LinkButton

 

<ajax:UpdatePanel ID="updClientesEncontrados" runat="server">
<ContentTemplate>
<Controles:GridView ID="gdvClientesEncontrados" runat="server" 
AutoGenerateColumns="False" CellPadding="3" CssClass="tabela_03" AllowPaging="True" AllowSorting="True" 
OnRowDataBound="gdvClientesEncontrados_RowDataBound" DataKeyNames="UnificaPessoaGrupoPK" Width="100%" PageSize="5"
onselectedindexchanging="gdvClientesEncontrados_SelectedIndexChanging" 
ControleAcesso="False" meta:resourcekey="gdvClientesEncontradosResource1">
<SelectedRowStyle Font-Bold="True" Font-Italic="False" Font-Overline="False" Font-Strikeout="False"
Font-Underline="False" />
<AlternatingRowStyle BackColor="#DFF0F9" Font-Bold="False" Font-Italic="False" Font-Overline="False"
Font-Strikeout="False" Font-Underline="False" />
<RowStyle BackColor="#B5DAEE" Font-Bold="False" Font-Italic="False" Font-Overline="False"
Font-Strikeout="False" Font-Underline="False" Wrap="False" />
<HeaderStyle CssClass="aba_on" Font-Bold="True" HorizontalAlign="Center" ForeColor="Desktop" />
<Columns>

<asp:TemplateField ShowHeader="False">
<ItemTemplate>
<asp:CheckBox ID="chkSelecionar" runat="server" Checked="false" AutoPostBack="true" OnCheckedChanged="chkSelecionar_CheckedChanged"/>
</ItemTemplate>

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<ControlStyle Width="5px" />
</asp:TemplateField>

<asp:BoundField HeaderText="Nome Completo" DataField= "NomePessoaCandidata" meta:resourcekey="BoundFieldResource1">
<headerstyle font-bold="True" horizontalalign="Left" verticalalign="Middle" width="350px"></headerstyle>
<itemstyle font-bold="True" horizontalalign="Left" verticalalign="Middle" width="350px"></itemstyle>
</asp:BoundField>




<%-- LinkButton que deve chamar a pop-up--%>
<asp:TemplateField headertext="Grupo Situa‡Æo">
<ItemTemplate>
<Controles:LinkButton ID="lkbGrupoSituacao" target="_blank" Text='<%#Eval("Status")%>' runat="server">
</Controles:LinkButton>
</ItemTemplate>
<ItemStyle Font-Bold="True" Font-Underline="True" HorizontalAlign="Center" />
</asp:TemplateField> 

<%-- LinkButton que deve chamar a pop-up--%>

</Columns>
<PagerSettings Mode="NumericFirstLast" PageButtonCount="5" Position="Top" />
<PagerStyle HorizontalAlign="Right" CssClass="innerTable"/>
</Controles:GridView>
</ContentTemplate>
<Triggers>
<ajax:AsyncPostBackTrigger ControlID="imbVoltar" EventName="Click" />
<ajax:AsyncPostBackTrigger ControlID="imbLimpar" EventName="Click" />
<ajax:AsyncPostBackTrigger ControlID="imbBuscar" EventName="Click" />
</Triggers>
</ajax:UpdatePanel>