I have a strange problem. While populating formfields, the values are maintained when clicking a'submit' button that causes the page to proceed to the next stage. I try to populate a hidden field from the code behind on the event of a 'find 'button click (before clicking this 'submit' button and this works. But the value is not maintained within the hidden field when clicking the 'submit' button of that page.
Any ideas why this is?
Thanks,
(Edit to clarify) The value of form fields gets posted back to the server when the form is submitted. If you have an input that is set as type hidden and you set the value of it such that it renders in the source (look at the source after hitting your find button) then the new value will post back as well.
Check if this is the case or if you have anything else overwriting the value.
Related
I have dropdown and texboxes and one button on the form. I'm using 'autopostback=true' for all the form elements. When you fill the form you need to push 'send' button. But because of texbox.autopostback, you need to push 2 time to send form.
If you select dropdown lastly, then there is no problem. But if you're filling textboxes than you need to click 2 time to send form.
Is there any solution for it? I must use textboxes.autopostback='true' but need some solution.
Thanks,
UPDATE:
All controls stays in updatepanel element.
Set a hidden field value to "1" when textbox posts back and its value is valid, else set the hidden field value to "0"
On client-side, in pageLoad event, automatically click the button if the hidden field value is "1". So, to the user button is only clicked once and your auto submitting the form when text post back returns.
Both the above points need to be done in your code-behind.
The result of of this logic will enforce a consistent workflow, where the button can be clicked only once to submit the page.
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.
First off, I have managed to create a web application where my dynamically created user controls are recreated and repopulated with the correct information upon postback. I am not sure what my problem is, but i hope that you will be able to help me figure it out based on my situation:
On my page i enter the number of controls to be created into a hardcoded textbox (its on the aspx page) and click the okay butten. This in turn, creates the specified number of user controls dynamically using c# in the background.
So far the desired number of dynamic controls are in a table on the page.
Next...
I have 1 textbox and 4 dropboxes on each dynamic user control. When i type a company name into the textbox field and press enter or click away (on text changed event) it autoposts back and the textbox retains the company name that i have typed in.
Based on this string the dropboxes are populated from the database. Now when i select the desired items from the dropboxes and click on the save button (located outside of the dynamic controls, on the page) it does an insert to the database, but it turns out that upon this postback the indexes from the dropboxes have been reset and the wrong values get inserted.
The following pictures show firstly, how it should be and then how it is.
Basically the company name remains in the textbox of the dynamic control, but the information i choose from the dropbox resets to the first index.
It's hard to tell what happend without code, but this is a common mistake:
If you fill/create the dropdownlist controls in the page load event and you post back, the code will refill/recreate the controls. That's why you have to use something like If(!IsPostBack) in your page load event. Otherwise it will execute that code everytime you do a postback and actually just want to execute the code in your event handler for that button.
If you're dynamically creating the controls, make sure to do that in the Page_Init event. Dynamic controls have to be recreated on every postback. Their state is restored after the Page_Init (if it is a postback), so make sure to only set their values in Page_Load if you want to overwrite them.
I am dynamically generating the form based on the drop down selected.
The form consists of fields (data entry for decimal values + few text fields). Have to add all the decimal values at the end and update the Total TextBox with that value. Total Textbox is disabled.
When I click Save button on the form after the user have entered their values, whole form is persisted in viewstate except the disabled textbox. When I enable the textbox, everything works fine. Mind you, I am dynamically generating the form and updating the value of the total textbox using javascript to calculate (adding all decimal fields).
P.S. I am doing everything right for persisting the viewstate.
So what has the enabled/disabled got bearing on the viewstate
Basically, I added two statements to get it working.
txtBox.Attributes.Add("readonly", "readonly");
txtBox.Style.Add("color","gray");
When I used txtBox.Enabled = false, it didn't persist viewstate but did it alternatively using above two statements in my code-behind page
Yes, disabled form element will not send it's value to server side, you can look request header. disabled element not appeared at "get" or "post" collection.
If you want set user can't edit it, you can set it as readonly.
Add javascript on the page:
function enableTextBoxes() {
$("input[type='text'][disabled='disabled']").removeAttr("disabled");
}
And add to server code (in Page_Load, PreRender or some else method)
ClientScript.RegisterOnSubmitStatement(typeof(Page), "enableTextBoxes", "enableTextBoxes();");
If you use UpdatePanels then utilize the ScriptManager.RegisterOnSubmitStatement method
Please create custom text box rather than using actual textbox instance.
inherit textbox in your custom textbox and add this textbox in your dynamic form.
I have several "ASP:TextBox" controls on a form (about 20).
When the form loads, the text boxes are populated from a database.
The user can change the populated values, and when they submit the form, I take the values posted to the server and conditionally save them (determined by some business logic).
All but 1 of the text boxes work as intended.
The odd box out, upon postback, does not contain the updated value that the user typed into the box.
When debugging the application, it is clear that myTextBox.Text reflects the old, pre-populated value, not the new, user-supplied value.
Every other box properly shows their respective user-supplied values.
I did find a workaround.
My solution was to basically extract the text box's value out of the Request.Form object: Request.Form[myTextBox.UniqueID], which does contain the user-supplied value.
What could be going on, here?
As I mentioned, the other text boxes receive the user-supplied values just fine, and this particular problematic text box doesn't have any logic associated to it -- it just takes the value and saves it.
The main difference between this text box and the others is that this is a multi-line box (for inputting notes), which I believe is rendered as an HTML "textarea" tag instead of an "input" tag in ASP.NET.
Are you initially loading the data only when !Page.IsPostBack? Also, is view state enabled for the text box?
this happens to me all the time.
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
// populate text boxes from database
}
}
I would second Jonathan's response I would check your databinding settings.
If you do not need ViewState for the textboxes (i.e. no postback occurs until form submit) then you should disable it.
It sounds like you are not having problems saving the data (since you said you have managed to get the control to read the correct data back). Therefore, I would say the problem loads in your databinding code.
Remember the order of the page lifecycle, and where you are databinding your form.
PreInit
Init
Load
Your Control Event Handler
If you are reading the value in the Control Event handler, yet databinding in Init or Load, you'll have the old value.
The trick is to always databind in the correct event, or check for postback and don't databind then.
Are you initially loading the data only when !Page.IsPostBack? Also, is view state enabled for the text box?
I had almost forgotten to check the ViewState, but ended up remembering to verify that it wasn't disabled before making my post here on SO. I even set EnableViewState="true" to make sure.
I did find the solution, and it coincided with most of the answers here. The form was indeed loading its data more than once (which is intentional behavior). I implemented some special code for this field, and all is well.
Thanks for your replies, all!