How do I make a DevExpress button use a callback instead of a postback?

This will will postback:

<dx:ASPxButton runat="server" ID="Button" />

 
 

This revamp can postback:

<dx:ASPxButton runat="server" ID="Button" AutoPostBack="False">
   <ClientSideEvents Click="AddEditButton_Click" />
</dx:ASPxButton>

 
 

You will need a JavaScript event like so:

function AddEditButton_Click(s, e) {
   MyCallback.PerformCallback("whatever");
}

 
 

MyCallback would be the name of a ASPxCallbackPanel wrapping all of the controls that use it. It will have a callback event.