Refresh a control on the master page after postback - asp.net

What i am trying to do here is to show a couple of validation messages in form of a bulletlist, so i have a Div on my master page containing a asp:bulletlist. Like this:
<div>
<asp:BulletedList ID="blstValidationErrorMessage" runat="server" BulletStyle="Disc">
</asp:BulletedList>
</div>
When i then click the Save button from any of my pages (inside the main contentPlaceHolder) i create a list of messages and give this list as datasouce like this:
blstValidationErrorMessage.DataSource = validationMessageCollection;
blstValidationErrorMessage.DataBind();
The save button is located inside an updatepanel:
asp:UpdatePanel runat="server" ID="UpdatePanel" ChildrenAsTriggers="true" UpdateMode="Conditional">
Nothing happens, i can see that the datasource of the bulletlist contains X items, the problems must arise because the Save button is inside an update panel and the elements outside this updatepanel (master page controls for example) is not refreshed.
So my question is, how do i make the bulletlist refresh after the postback?
Thanks in advance.

If your button is inside an UpdatePanel, you should place your BulletedList control inside an UpdatePanel too.
You can place an UpdatePanel surrounding the BulletedList in the MasterPage file. Set "UpdateMode" to "Conditional" then call the Update method of the UpdatePanel to refresh only when needed ('save button' click for example).

The Save button will only update the contents of the UpdatePanel you placed it in. Here's what I recommend doing:
Move the SaveButton outside of the UpdatePanel. Where you put it I'll leave up to you.
Put your validation div inside another UpdatePanel. Call it ValidationUpdatePanel
Add your SaveButton as an AsyncPostbackTrigger for both update panels. Since you may have each UpdatePanel separated into different controls/pages, you'll probably want to do this in the code-behind programmatically.

Related

ASP.NET webform Fileupload inside an ascx which is inside an updatepanel in the aspx

here is some code in my page :
<asp:UpdatePanel ID="UpdatePanelEQSelector" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<uc12:EQSelector ID="custEQSelector" OnEqChange="custEQSelector_OnEqChange" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
Inside my user Control, I'm asked to add a fileuploader.
After coding it simply, I tested and my fileuploader is always empty.
I've searched a while and discovered that it was a normal behavior.
The solution to make it work is to add a PostBackTrigger for the updatePanel.
When I tested it in my aspx page, I achieved to do it and my fileUploader had the file.
Then I tried to add it dynamically (to finally do it in my control), it worked with that :
PostBackTrigger trigger = new PostBackTrigger();
trigger.ControlID = this.btnTest.ID;
this._UpdatePanelEQSelector.Triggers.Add(trigger);
But I can't manage to make this code work in my control (I passed my updatePanel as a parameter to my control set in Load, the fileUpload is always empty)
Do you see a solution ?
Thanks
Does it postback, but leaves the control empty? or is it not posting back at all. If it's not posting back at all I'd add this
ScriptManager.GetCurrent(this).RegisterPostBackControl(btnTest);
to the page_load of the user control.
If it is posting back, but the control is empty, then I'd wager there is probably some dodgy html somewhere on the page and the values are getting lost.

update panel does not working for views

i am using updatepanel for a linkbutton so that it doesnot refresh the whole page . on click of that linkbutton i need to set an active view in a multiview control which is working fine without updatepanel.
but when i use updatepanel it doesnoot work. can you help me how to do this
updatepanel code
<asp:UpdatePanel ID="UpdatePanel3" runat="server">
<ContentTemplate>
<asp:LinkButton ID="changephoto" runat="server" ForeColor="Blue" OnClick="changephoto_Click">Change Photo</asp:LinkButton><br /><br />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="changephoto" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
on click event
Protected Sub changephoto_Click(ByVal sender As Object, ByVal e As System.EventArgs)
MultiView_Updates.SetActiveView(View_ChangePhoto)
'bindprofileimage()
End Sub
put the multiview inside the updatepanel.....
If you want set view on click of the linkbutton which is placed inside the update panel, then your Multiview must also be present inside the update panel. Otherwise, the control will not be refreshed.
UpdatePanel controls work by specifying regions of a page that can be updated without refreshing the whole page. An asynchronous postback behaves like a regular postback in that the resulting server page executes the complete page and control life cycle. However, with an asynchronous postback, page updates are limited to regions of the page that are enclosed in UpdatePanel controls and that are marked to be updated. The server sends HTML markup for only the affected elements to the browser.
Using Nested UpdatePanel Controls
UpdatePanel controls can be nested. If the parent panel is refreshed, all nested panels are refreshed also.
The following example shows markup that defines an UpdatePanel control inside another UpdatePanel control. A button in the parent panel triggers an update of the content in both the parent and the child panel. The button in the child panel triggers an update of only the child panel.

UpdatePanel refreshing with <input type="image"> but not type="button

I have an UpdatePanel control in my ASP.NET application (actually several, but that's not the concern).
<asp:UpdatePanel ID="UpdatePanelDetail" runat="server" UpdateMode="Conditional">
<ContentTemplate>
...More code here
Inside the panel, there exists an asp:Table object:
<asp:Table ID="tblGIFs" runat="server"></asp:table>
This table gets programmatically generated via some code from codebehind:
TableRow htr = new TableRow();
TableCell htc = new TableCell();
...<snip>
tblGIFs.Rows.Add(htr)
And that's all fine, except in one of the cells I am trying to add a button (with an image):
htc3.Text = "<input ID=\""+ii.Value+"\" OnClick = \"btnGIFSearch(this)\" type=\"image\" value=\"/Image/Fiu.png\" />";
When this image is clicked, the onclick fires fine, but the entire UpdatePanel gets refreshed (and consequentually, the asp:Table disappears).
If I use a type="button", it works completely fine and there's no issue with refreshing/losing the content in the table.
I've run the page with breakpoints on every location that I'm touching the table from codebehind to no avail, there's really nothing more that I can see that could cause the UpdatePanel to be cleared programtically.
Anyone seen similar behavior with these tags/controls and any idea of a resolution? A workaround is obviously using type=button and just styling the button, but I rather not do that if I can get type=image behaving correctly.
An input type "image" is like a submit button. It's submitting the form, because that's what they do. If your code-behind is not rebuilding the table in the case of a postback that you don't expect, the table won't be rebuilt, and hence disappear (keep in mind whenever you build controls dynamically, you must do so every request). If you don't want the button to postback, have your OnClick handler return false to cancel the post. If you DO want the button to postback, then you have a different problem, probably related to using dynamic controls incorrectly.
Solved with dynamically created controls.

ASP.NET - reload a dropdown?

I have a dropdown which shows filesnames and when the index is changed, the slected file is offered for download. I also have a button which creates new files ... now after a new file was created, the new filename should also be shown in the dropdown. It works fine, when I refresh the page, but this is not what I want.
I tried putting the dropdown in an updatepanel and giving it the file create button id, it failed ... is this the correct apporach or is there an easier way?
Thanks!
I just cant get it to work, this is my code:
<asp:UpdatePanel ID="UP_ExportInvoices" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:DropDownList ID="DDL_ExportFileDownLoad" runat="server" AutoPostBack="true"
OnSelectedIndexChanged="DDL_ExportFileDownLoad_SelectedIndexChanged">
</asp:DropDownList>
</ContentTemplate>
</asp:UpdatePanel>
I was thinking that if the UpdateMode is set to Always, that the content is always updated? I also have that button (asp:ImageButton) which resides outisde this UpdatePanel. I tried adding a Trigger fpr that button, but it did not work. What am I making wrong. So far, im only thrwoing exceptions or the dropdown is not updated.
Thanks :)
If you are creating the file in the same page, then just append the file name to the dropdown. Can you do this trick in your application?
Does you button posts back the page? If yes, then you need to rebind the drop-down again after you create the file in button click handler.
If button makes partial post-back (say it is placed within UpdatePanel) to the server then above will be still applicable but dropdown should also be in UpdatePanel.
You need to ensure that the Button is a trigger for the Update Panel, or is a child within it.
Here is a full explanation:
http://www.asp.net/ajax/tutorials/understanding-asp-net-ajax-updatepanel-triggers
You need to place the button within the UpdatePanel. This will cause a partial postback and the dropdown should re-bind, showing the new item. Alternatively you can include JavaScript in your page which adds the new item to the dropdown list on the client-side, however this can sometimes cause problems with ASP's automatic event validation.

Updating a control outside the UpdatePanel

I have the following ASPX structure:
<UpdatePanel id="OutsidePanel" UpdateMode="Conditional">
<div runat="server" id="myDiv">
<UpdatePanel id="InsidePanel" UpdateMode="Conditional">
<asp:ImageButton that causes a postback.. />
</UpdatePanel>
</div>
</UpdatePanel>
When the imageButton is clicked, on the server side, I change the class of myDiv. It's not getting updated. I assume this is because the div is outside of the Inside UpdatePanel. How would I force it to update?
Could you not just call the Update method of the "OutsidePanel" UpdatePanel on the server when the Imagebutton in "InsidePanel" causes a postback? Or alternatively, set up ImageButton click event as a trigger for "OutsidePanel"
According to MSDN
If the UpdateMode property is set to
Conditional, the UpdatePanel control's
content is updated in the following
circumstances:
When you call the Update method of the UpdatePanel control explicitly.
When the UpdatePanel control is nested inside another UpdatePanel
control, and the parent panel is
updated.
When a postback is caused by a control that is defined as a trigger
by using the Triggers property of the
UpdatePanel control. In this scenario,
the control explicitly triggers an
update of the panel content. The
control can be either inside or
outside the UpdatePanel control that
the trigger is associated with.
When the ChildrenAsTriggers property is set to true and a child
control of the UpdatePanel control
causes a postback. Child controls of
nested UpdatePanel controls do not
cause an update to the outer
UpdatePanel control unless they are
explicitly defined as triggers.
If you are updating the class server-side, then the answer is yes. The inner update panel is being rerendered and passed back to the client, but the outer update panel is not being replaced. Anything outside the actual panel being updated won't be replaced when the AJAX callback returns. You might want to consider adding some javascript that updates the div when the result is returned as a simple solution to changing the class.

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