using autopostback on dropdownlist that also has submit button - c#

Have a dropdown list with autopostback set to 'yes' have another dropdown list box that will be populated based on the selection of the first dropdown. It works fine until I put a submit botton on the form. When I do it appears to not do the auto postback until the submit button is pushed. Can you have a submit button on a form that has a dropdown with autopostback active. thanks...

Sure you can.
Are you handling the autopostback event of the first dropdown in the code-behind file to populate the second dropdown? If so, your postback event should be firing when you change your selection in the first dropdown. Put a breakpoint in your code to assure that your event code is being called.

Sure you can. Are you seeing it not load the second dropdown? If so, check where you're handling that, as it may be in the wrong spot (if you're doing it with code) or you might have it wrapped in a !postback without thinking about it. Post more code and explanation for more help.

Related

Must click a button twice to fire an event

I have a data grid that is created dynamically to display information retrieved from a database. The data grid consists of multiple bound columns and two button columns for each row, a view and a delete button.
Clicking either button calls the Page_Load() method with Page.IsPostBack as false.
if (!Page.IsPostBack)
{
this.bindForm(); // Populates drop down lists that the user can select
setAccess(false); // Sets access for the page
// Stuff commented out to avoid confusion
}
else
{
bindDynamicGrids(); // Create the data grid(s) and populate them
}
So when I first click the button the above code gets called with IsPostBack false, and the dynamic grids get bound. But, the button click event does not fire. When I click the button a second time, Page_Load is called with IsPostBack false, and after executing bindDynamicGrids() the button click event is fired. I cannot understand the difference between the first and second click.
I have read a few threads;
ASP.NET C#, need to press a button twice to make something happen
http://forums.asp.net/t/1783694.aspx?ASP+NET+Button+needs+to+be+clicked+twice
To attempt to understand the issue, but I must be missing something. From what I am gathering from the second link, a session variable may be getting set in the click event, which is also being set in Page_Load, and this is all an issue with ordering. If that is the case I am not seeing where it is happening.
When it is not a post back the bindForm() method is called, which populates all drop down lists. The edit click event populates those drop downs with the values from the row, but the click event is always a post back and the form has already been bound.
I have also considered having a script automatically double click one of the buttons anytime the user single clicks, but I have not been able to find an "OnClick" property for the column button. Any help that could be provided would be phenomenal.
The thing is, that the button click event happens after the Page_Load event meaning that the filtering does not get applied on the first postback. It has been updated on the second postback and you see the filtering.
You can try to move the code of your page_load event to OnPreRender so the reload happens after the button click event.
for more information look here: Button needs to be clicked twice
and here

AutoPostBack ONCE on pageload

I have a listview with a dropdown, with autopostback enabled.
The user can select yes - which postsback and brings up loads more dropdowns, no - which brings up a textbox, and blank - which does nothing.
As the original dropdownbox is databound it displays one of those values but at the moment always acts as if it was blank ie no other controls showing..
Can I make the page do ONE autopostback as soon as it's loaded without any user input to display the correct controls if it's a yes or no as opposed to blank?
try calling dropdownbox_selectedindexchanged(null,null) after binding in page load. it is just calling selectedindexchanged event programmatically. as far as i know you want to load controls based on dropdown selection when page first load and user haven't changed dropdown value. so this code will call it from code behind.

Enable/disable TextBox on FormView.ModeChanged

I have DropDownList and a TextBox in the EditTemplate of my FormView. All I want is to enable/disable the TextBox based on whether the first entry of my DropDownList is selected:
When the FormView is switched to Edit mode by the user
When user changes the selected item of the DropDownList during Edit mode.
I have achieved the second one through JS and that's working fine, but the first one is proving too difficult. I've tried to do this in ModeChanged event of the FormView, but for some reason the following call returns null in the event:
MyFormView.FindControl("MyDropDownListID");
What am I missing here?
(I'm making sure that MyFormView.CurrentMode is FormViewMode.Edit before making the above call)
One of those times when you pull your hair for hours with a problem, then post it on SO and find the solution in the next few minutes. Anyone else trapped into this, the problem is that the controls of a databound FormView aren't created yet at the time of ModeChanged or Page_Load. You must call the above line in DataBound event and it will work fine.

How can I load data when I click in another box?

I have an autocomplete on my page where I use it as a search. I want to be able to select an item that appears in the autocomplete and then when the user clicks another box it will do a postback and if there is data for the one selected, it will populate the other fields for that chosen selection.
So what I am asking, is how would I go about doing a postback when the user clicks into another textbox on the screen?
Hi you could use event from textbox (TextChanged) inside this event put your code to verify if this data is correct. Don't forget put property AutoPostBack from textbox in True. This action only can be use if the data in textbox change if for example you put
My Dog
and data not exists if you change focus nothing will happen until you change the data for example
My Cat

TextChange in Gridview Textbox prevent button event

I have a text box on a Gridview which I'm allowing some data to be edited. When the enter key is hit, the TextChanged event happens, like I'd expect. But when i change the data and click a button, the button effect not happen. I must click the button again to fire button event. I think it happen because the grid didnot lost it focus.
How to make it possible fire the button event just in one click?
You can change your gridview element's IsTabStop property to false to gain that effect.
Also if you want to cycle with Tab you can TabNavigation="Cycle" .
Both changes are in xaml.
Not much we can do to help you here without the code itself but here are couple things you could try to debug this:
Try different browsers – it may be a browser issue
Try some client side debugging – just open console and see if anything happens when you click the button for the first time

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