How to handle PostBack inside ASP.net Custom Control

Question

May be I am missing something important in order to implement CustomControl properly as per requirement or having a lack of knowledge. Actually I have Created CustomControl (.dll)for searching purpose having 3 Dropdown boxes(populating from database), 1 textbox and search button, after choosing appropriate filter criteria user clicks on Search button and simple gridview appears. My problem is I dont want to fill dropdown boxes in CustomControl on every post back(fired from page).

Do you check the IsPostback property in the control on Page_Load? — Tim
– Tim, Commented Jun 28, 2014 at 8:48
I am not getting IsPostback property, I implemented override void OnInit(EventArgs e) & override void CreateChildControls() — Vishwanath Mishra
– Vishwanath Mishra, Commented Jun 28, 2014 at 8:53

Aristos · Accepted Answer · 2014-06-28 09:50:17Z

2

When you are in a place that can not spot the Page you can use this global parameter:

System.Web.HttpContext.Current

Now from that you can get the Page if its available,

Page page = HttpContext.Current.Handler as Page;

if (page != null && page.IsPostBack)
{

}

or you can get the Form and the post back values using

System.Web.HttpContext.Current.Request.Form

and check if the Form have values, then is probably post back.

Just a note, always check if the System.Web.HttpContext.Current is not null before using it, because if you call it from a thread and there is no page available, then is null.

answered Jun 28, 2014 at 9:50

Aristos

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2 Comments

Vishwanath Mishra Over a year ago

Hi Aristos! thanks for your answer, now I am getting PostBack, but my problem was as it is, when second time CreateChildControls() calls, if doesn't load values in dropdown boxes, it gets lost.

Aristos Over a year ago

@VishwanathMishra Maybe then the viewstate for this control, when they use it, is disabled. (or you did not save on viewstate this controls)

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