When should you use Page.DataBind() versus Control.DataBind()?
In ASP.NET, you can bind controls individually (i.e. GridView1.DataBind()
) or you can call Page.DataBind()
to b开发者_开发问答ind all controls on the page.
Is there any specific difference between the two calls? Are there times when one should be preferred over the other?
Page.DataBind
is Control.DataBind
. Neither the Page
class, nor the TemplateControl
class overrides Control.DataBind
.
Control.DataBind
does little more than call OnDataBinding
for the control, then it calls DataBind
for each child control.
For choosing between Page.DataBind()
versus Control.DataBind()
, here is the Microsoft guidance :
"Both methods work similarly. The main difference is that all data sources are bound to their server controls after the
Page.DataBind
method is called. No data is rendered to the control until you explicitly call either theDataBind
method of the Web server control or until you invoke the page-levelPage.DataBind
method. Typically,Page.DataBind
(orDataBind
) is called from thePage_Load
event."
There will be cases when you want specify control databinding individually, depending on the current page scenario. For a detailed level of control over which controls are bound and when controls are bound, I opt for the control-level DataBind()
methods.
In an ASP.NET page, you can bind directly to public/protected properties of your page's code-behind class. For example:
<form id="form1" runat="server"><%#HtmlUtility.HtmlEncode(MyProperty.ToString())%></form>
In this case, there is no specific control to call .DataBind() on - the page itself is the control. It just so happens that calling Page.DataBind() will also call DataBind() on all child controls, so if you're already doing a Page.DataBind(), there's no need to data bind the controls individually.
This is not a direct answer to subtilities between the two calls, but
about DataBind()
vs Page.DataBind()
I would like to share an interesting experience which may also really guide you to chose between both :
I just spent one complete day to figure why Ajax calls and events in a huge webapplication were broken (ItemCommand
not raised on callbacks and postbacks, lost references, etc).
The reason was I had one ASCX which made a call to Page.DataBind()
rather than DataBind()
on itself.
It could seem obvious when you found it, but when you are dealing with weird behavior in a >500000 lines application and a lot of complexity in master/pages/controls, it's not.
So beware of Page.DataBind()
if you call it at the wrong place !
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