Partial postback with Javascript
You can use an AsyncPostBackTrigger with the UpdatePanel to do this. Because you need something that can fire an event, using a button is fairly simple and when hidden works nicely.
If this is your markup:
<asp:UpdatePanel ID="UpdatePanel1" runat="server" OnLoad="UpdatePanel1_Load"> <ContentTemplate> <!-- Contents... --> </ContentTemplate> <Triggers> <asp:AsyncPostBackTrigger ControlID="ReloadThePanel" EventName="Click" /> </Triggers></asp:UpdatePanel><asp:Button ID="ReloadThePanel" runat="server" style="display:none;" />
When you want the panel to be updated, you just need to call:
__doPostBack('<%=ReloadThePanel.ClientID %>', null);
This will make ASP.NET think that ReloadThePanel was clicked and the JavaScript auto-generated due to the trigger will handle the rest.
EDIT
You can do a pure JavaScript update of the UpdatePanel without any triggers or hidden buttons. You just need to invoke __doPostBack
with the client-side ID as the first argument.
__doPostBack('<%=UpdatePanel1.ClientID %>', null);
I used @MatthewJacobs' answer but I found that the call to __doPostBack
caused a runtime exception on IE11. I found that the call to __doPostBack
can be replaced by the following JavaScript call, which worked on both browsers I tested (IE11 and Chrome 52).
Sys.WebForms.PageRequestManager.getInstance().beginAsyncPostBack( [ '<%=UpdatePanel1.ClientID %>' ], '<%=UpdatePanel1.ClientID %>', null);
See Sys.WebForms.PageRequestManager.beginAsyncPostBack Method for more details.
The solution that worked for me
ASPX
<script> function myfunc(){ __doPostBack('<%=UpdatePanel2.ClientID%>', ""); }</script><asp:UpdatePanel ID="UpdatePanel2" runat="server" OnLoad="UpdatePanel1_Load"> </asp:UpdatePanel>
.cs
protected void UpdatePanel1_Load(object sender, EventArgs e){ if (IsPostBack) { //your code } }