Returns a client side Postback Event link (__doPostBack() call) that can be used to fire a server side event from client code.

A common way that this function would be called is from a Grid Column Expression. Here's an example:

<ww:wwWebDataGridColumn runat="server" ID="WwWebDataGridColumn1" 
      Expression="HREF( this.Page.GetPostbackEventReference('Page','DeleteCompany',Trans(pk),.t.) ,[Delete])" 
      HeaderText="Action" >

This code uses the HREF() expression to generate a hyperlink and the link itself is set by the GetbackEventReference method. The output from this function generates something like this:

__doPostBack('Page','DeleteCompany','10');

Actually the output in this case is used for a HyperLink so the final parameter llIsLink is passed as .T. which prefixes the javascript: text to the link so the actual output is:

javascript:__doPostBack('Page','CustomerDeleted','10');

The latter is required only if you embed the link into an HREF expression. If you call this code from elsewhere (say in a JavaScript function) the javascript prefix is not required.

Remember if you manually use __doPostback() from script code, you have to ensure that this.Page.RegisterPostbackScriptCode was called somewhere in your code to ensure the postback script is included in the page source.

Other ways to use this method

You will frequently want to assign this method dynamically for navigation expressions. For example you might do the following in a Repeater:

<ww:wwWebImageButton runat="server" ID="btnDelete" 
                    Click="btnDelete_Click"
                    ImageUrl="~/images/remove.gif"
                    UrlControlSource="this.Page.GetPostbackEventReference('Page','btnDelete_Click',TRANS(pk),.T.)"
/>

You can then handle this event as follows inside of the page:

FUNCTION btnDelete_Click()

*** Retrieve the event parameter (same as: Request.Form("__EventParameter") )
lcId = this.GetPostBackEventParameter()

*** Do something with the value
this.oEntry.Delete( VAL(lcId) )
ENDFUNC

o.GetPostbackEventReference(lcControlId,lcEvent,lcParameter,llIsLink)

Page.GetPostBackEventParameter()

javascript:__doPostBack('Page','CustomerDeleted','10');