I have a visual web part (sandboxed) that visualize a form for adding sub-sites. When a sub-site is added its added in the navigation and in a DropDownlist (for delete purpose...).
My problem is that after post-back everything works fine, except i have to manually reload the page to see the new changes (both nav. and dropdownlist). Note that neither Response.Redirect or UpdatePanel will work i a sandboxed-solution.
Anyone got a solution to this problem?
When you perform a postback, your browser submits the contents of all web controls to the server. The server is stateless in this sense; the state of the control is actually stored in your browser. I would say your problem occurs because the web controls are not populated from SharePoint object model. Instead, the server uses the data received as the postback. Alternatively, the population might even happen, but the postback data will overwrite the contents of controls.
The solution is to refresh control data after the controls have been populated from the postback data. You could do this, for example, in the method OnPreRender. When OnPreRender is called, all the postback data has already been processed.
Try to add the following code in your webpart class.
protected override void OnPreRender(EventArgs args)
{
if (this.Page.IsPostBack)
{
// Repopulate controls here
}
}
The problem of this is, of course, that repopulation will kill the previous (postback) state of the controls. So, if you want to preserve the current value of a control (such as a dropdown selection), you must save it before repopulation and restore it manually.
To learn more about the page lifecycle in ASP.NET, see ASP.NET Page Life Cycle Overview.
Related
I've got an issue due to a timing issue with react-admin, that i'm looking for a little help on.
The situation is where user A creates a resource, and user B, on a different PC, then goes to list and edit that resource.
For user B, the list page loads the full dataset of 10 resources, then the edit page re-loads the single resource that is being edited.
However, the specific process on the edit page seems to be:
Render page
Render resource cached from the list page
Request the single resource from the API
Populate the edit form with the updated values from the API
Set the form to dirty
That last point is critical, since I have an action button that is only enabled if the form is pristine, so the user has to save any changes before triggering the action.
But in this case, the list view and the edit view seem to return the same data for the resource, so I'm not sure why the form is being set to dirty.
Any thoughts?
Regards,
Andy
This isn't a complete answer, but I hope it helps you save some time. I recently upgraded React Admin version from 3.5.3 to 3.6.0. I noticed that the Save button is now sometimes disabled unexpectedly, and inconsistently. For example, I may navigate to the edit view of a resource by clicking a link and the Save button is enabled, but if I refresh the page, the Save button is disabled. Apparently, the Save button is supposed to be disabled when the form is pristine. So between 3.5.3 and 3.6.0, it seems that some changes were made to either the pristine handling or the Save button's reaction to pristine, and it is not working consistently.
I see there is a new issue opened three days ago regarding overriding the Save button behavior, wrt pristine. https://github.com/marmelab/react-admin/issues/4913 . So, it seems the dust hasn't settled on this behavior. Perhaps a bug will be found.
In one of my custom application user wants to keep EditForm.aspx open once list item is created and he can keep saving the same record without redirecting user to DisplayForm.aspx page.So what I'm doing after list item creation I'm loading EditForm.aspx again.
Now the problem is when form is opened in Edit mode and if existing field is modified that doesn't gets updated in the list item but if something new added to the field then it gets saved to the list. I believe it's postback issue but not sure how to pass latest form data upon save.
If this was my task, I would create a new application page that replaces the edit page on that list.
(You can use powershell / object model to set the url of the new / edit / display pages)
Ignoring the ribbon, the edit page is actually pretty simple. It shouldn't be too difficult to create a custom one, that has the submittal behavior you are interested in. Indeed, since you are keeping the exact same field names and input types, you may be able to simply inherit the default form in yours, and simply override the post call.
I suppose it might be possible instead for you to write some javascript to hijack the submit post of the default edit page, but this seems messy to me, and I probably wouldn't go that route.
If you don't need to complete this task today, I've been meaning to push to github some code I wrote a few months ago. That code is a custom aspx edit/new/display page that is extremely easy to customize / implement. I could forward you the link tonight when I get out of work.
I am building a visual web part which has a number of user-configurable properties. The web part will display news items and, optionally, automatically switch to the next item after a defined pause.
The problem I'm having is that the user control part has a timer which fires events. These events reenter the user control (without going through the web part) and I see that when this happens the user control is in an unitialised state - i.e. the custom properties of the web part have not been applied. This causes the control to behave in it's default manner.
What am I doing wrong?
When you set property in your webPart, you need to bubble it down to the User control.
See creating custom properties for visual webparts:
http://patricklamber.blogspot.com/2010/05/how-do-i-create-custom-properties-in.html
I'm writing an intranet ASP.NET page using VB.NET. I've run into a particularly nasty problem dealing with handling file uploads. I'll do my best to explain the problem, and perhaps someone can help.
My problem is almost a duplicate of this one, or this one, except (other than the filename) I don't care about sending the file to the server until the other data has been reviewed.
Here's the situation:
Joe Q. Dataentry inputs some data into several fields. The first 3 are drop down, and when he changes the selection, a postback event is fired that queries a database for valid entries for the other drop down selections. After selecting the values, he inputs some other data, chooses a file to accompany the data and clicks the "Update" button. When he hits the button, it fires a postback event that sends the current data to the server to be validated. The data will create a change in the database, so he is presented with a view of the current state, and what it will look like when his changes are made. He can now either confirm or cancel the operation for whatever reason.
Part of the data he will see involves the extension of the file which may be a PDF, or could also be some image file or other document.
Now here's where my problem is - on each postback event, the fileupload dialog is cleared. I was getting around it by creating a temporary file on the first postback and then renaming if he clicks OK or deleting on Cancel... but I need to do a variety of things, based on the previous state of data and the filename. I've tried to keep some session variables to retain the filename, and that works OK for just renaming the file, but for what I need to do it gets unwieldy.
What I want to do is be able to have the postback event to present the changes, and then when the user clicks "OK", submit the file. Is there any possible way to do that?
One of my thoughts was to do some of the validation client-side (I'm already re-validating server side so I'm not too worried about data security there), but I don't know how I could get the information from the database query.
Thanks for any help, and reading my slightly convoluted story/situation!
EDIT:
It appears that what I want to do is prevent a certain button from firing a full postback. Is there any way to do that?
EDIT II:
I have an update panel on the page already - is there any way for the button to only post what's in the update panel?
What you might want to do is place your drop-downs inside of an ASP.NET AJAX UpdatePanel, and keep your file upload control out of that.
Your update panel will do the post backs and allow your validation logic to happen without submitting the file, then when you hit your final "Save" button (which is also outside of your UpdatePanel) the entire form will be submitted back and you can work with your file then.
We have a question regarding VB.Net 2008.
We are used control array in vb.net and third party timer controls.
When handle received from external application to timer control event procedure,
after this form becomes blank and controls disappear.
What we have to do to persist the controls.
You asked what you have to do to persist the controls. It's not clear whether you mean winforms or webforms, but I can answer for both possibilities:
If it's the former, you have it backwards. The default behavior of all controls is that they are "persisted" until you tell them otherwise. If anything disappears, it's because you have code somewhere that tells it to. That's where you need to start looking.
If it's webforms/ASP.Net, the problem is that you don't understand the page lifecycle. Everything that raises server events, including your third party timer controls, causes a post back. That's how events work - the browser posts the form back to the same url in such a way that the server knows to call a your event code at the right time. The thing here is that as far your server is concerned, it's still just a new http request, and that means you're working with a brand new instance of your page class every time this happens. If you've previously added some controls to your page, it doesn't matter. That was an old instance that was discarded and probably disposed by the time the page was visible in the user's browser. If you want to keep those controls, you need to make sure you add them to the page on every postback.