Dynamic dropdownlist control doesn't fire Selectedindexchanged event

I need to fire the Selectedindexchanged event of a dynamically created dropdownlist. I've no code in aspx page. All code are in codebehind.

DropDownList objdropDown = new Dr开发者_如何转开发opDownList();
objdropDown.EnableViewState = true;
objdropDown.AutoPostBack = true;                                
//objdropDown.AutoPostBack = true;
//objdropDown.SelectedIndexChanged += new EventHandler(objdropDown_SelectedIndexChanged);

protected void objdropDown_SelectedIndexChanged(object sender, EventArgs e)
{
    //My code here
}

After selecting a random item drom Dropdownlist, it postbacks but the dropdown control is not visible. What am I doing wrong here? Code would be helpful. Thanks!

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Because the code is generated in the code behind it will not be persisted between postbacks, except you explicitly recreate it each time (probably in Page_Load). But then you might have to track the item you selected and set that as selected after each regeneration on postback.

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You need to create the drop-down list & bind the event early, in pageInit. It will be then be aware that be able to participate in the postback process & raise events for selectedindexchange.

PageLoad is to late as postback processing has already occurred. Have a look at this: http://msdn.microsoft.com/en-us/library/ms178472.aspx

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Did you add the newly created DropDownList to it's parent Container on the Page and set its Visibility to visible?

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I have the same issue as this and just wanted to share my resolution for others. Please make sure

• The drop down control ID is the same across all the post backs (better set this to be on the safe side)
• Create the dynamic drop down in the page_Init event.

My issue is relating to the dynamic control ID being changed after post back. My issue is resolved after I make sure that the control ID the same across all post backs.