How to load only one tab content of a multi tab webpage?

You could fire an event from your first user control so that the page can handle this event and tell the other usercontrol to databind.

Here is a example

 ID="TabContainer2" runat="server" CssClass="EmployeeProfile" ActiveTabIndex="0"> 
 ID="TabPanel1" runat="server" HeaderText="Datos Generales"> 
   
     /> 
     ID="EmployeeGeneralDetails2" runat="server" OnUpdated="EmployeeGeneralDetails2_OnUpdated" /> 
   
 
 ID="TabPanel2" runat="server" HeaderText="Referenias Personales"> 
   
     ID="EmployeeResumeView2" runat="server" /> 
   
 
 











Here codebehind code
protected void EmployeeGeneralDetails2_OnUpdated(object o, EventArgs e) 
{ 
  EmployeeResumeView2.DataBind(); 
}