I am new with ASP.NET. This is my code:
<asp:UpdatePanel runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Button Text="Change" runat="server" ID="BtnChangeText" OnClick="BtnChangeText_OnClick"/>
<asp:Label runat="server" ID="LblTest" Text="Change me!"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
This is my server code:
protected void BtnChangeText_OnClick(object sender, EventArgs e)
{
LblTest.Text = "Hello World!";
}
Why does it not work?. How can I do for this work?
Thank in advance!
Add this after your </ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Change" EventName="Click" />
</Triggers>
You have set the updateMode property to Conditional so it will the updatePanel won't be refreshed automatically (as this was default)!!
Simpel solution set it back to Always
MSDN UpdateMode
Always
The content of the UpdatePanel control is updated for all postbacks that originate from the page. This includes asynchronous postbacks.
Conditional
The content of the UpdatePanel control is updated under the following conditions:
If the Update method of the UpdatePanel control is called explicitly.
If a control is defined as a trigger by using the Triggers property of the UpdatePanel control and causes a postback. In this scenario, the control is an explicit trigger for updating the panel content. The trigger control can be either inside or outside the UpdatePanel control that defines the trigger.
If the ChildrenAsTriggers property is set to true and a child control of the UpdatePanel control causes a postback. In this scenario, child controls of the UpdatePanel control are implicit triggers for updating the panel. Child controls of nested UpdatePanel controls do not cause the outer UpdatePanel control to be updated unless they are explicitly defined as triggers.
See MSDN for further details!
Related
I need to have UpdatePanel with asyncpostback, but in my case it seems that no partial postback happens, but fullpostback. I am new to web forms, please, check the code:
<%# Register TagPrefix="Cust" TagName="CompanyInformationView" Src="~/CustomControls/CompanyInformationView.ascx" %>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="Server">
<asp:UpdatePanel runat="server" ID="UpdatePanel1" ChildrenAsTriggers="true" UpdateMode="Conditional">
<ContentTemplate>
<asp:Button ID="Button1" runat="server" OnClick= "Button1_Click" Text="test" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
<Cust:CompanyInformationView ID="CompanyInformationView" runat="server" />
</asp:Content>
So I have Test Button. OnClick it should do "nothing" for test. Also there is custom control on web form. Here is server side code for this form:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
// fill in custom control
CompanyInfo c = GetInfo();
CompanyInformationView.Company = c;
}
}
protected void Button1_Click(object sender, EventArgs e)
{
var i = 1;
}
CompanyInformationView is custom control with property "Company". There is no ViewState added for this property (so it cannot be loaded properly if postback is done). When I click on Test Button, the page fails, because "CompanyInformationView.Company" is not set (it is not set, because it cannot be loaded from ViewState, I guess).
Instead, I think that it should not work like this. AsynPostback should deal only with UpdatePanel.
Why it wants to reload custom control? Doesn't it mean that Full postback happen or maybe I do not understand Asyncpostback?
PageLoad and all other events are raised on every get\postback, no matter if it's async or full,
In asyncpostback, the response which the server renders includes only the content inside the updatepanel.
Try to Put <asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
Before
<asp:UpdatePanel runat="server" ID="UpdatePanel1" ChildrenAsTriggers="true" UpdateMode="Conditional">
Async post back in web forms still proceeds the whole page life cycle as if it's a traditional post. the difference is only the updated content inside target update panel that will be sent in response. so in this case, async post back will still give you exception unless you populate the custom control no matter get/post.
you need to also put the custom control inside another update panel or in the same update panel as the button in order see partial update to happen.
I have created a custom UserControl in Asp.Net. This user control contains an asp:ImageButton wrapped in an UpdatePanel with a ScriptManagerProxy in the UserControl and a parent ScriptManger on the main page that contains the asp:Panel these custom UserControls are added to (renders as a list like object with items). I want to suppress the click from the ImageButton (contained in the UpdatePanel) to NOT fire PostBacks that is causing the page to be refreshed. Here is a snippet of the UpdatePanel wrapped ImageControl within the custom UserControl:
<asp:ScriptManagerProxy ID="ScriptManagerProxy1" runat="server"/>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" ChildrenAsTriggers="true" UpdateMode="Conditional">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="CatImage" EventName="Click" />
</Triggers>
<ContentTemplate>
<fieldset>
<asp:ImageButton ID="CatImage" runat="server" Height="128px" Width="128px" ImageUrl="../Handlers/ImageResizer.ashx?imgpath=../PhotographicImages/noImageFound.png&w=180&h=180" OnClick="CatImage_Click"/>
</fieldset>
</ContentTemplate>
</asp:UpdatePanel>
On the top of the main page that dynamically loads these UserControls to its asp:Panel is:
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
This works ONLY for every click AFTER the first click... Meaning the first click causes a PostBack on the main page, but any subsequent click is suppressed.
When this ImageButton is clicked, i fire an event in the CodeBehind to display a "LightBox" object with a larger version of the image.
What is wrong with this code? How can i suppress this first click from causing a PostBack to my parent page?
I have the following situation:
A master page with a usercontrol inside an update panel that triggers each minute by a timer.
In a content page i have an ajaxToolkit:AjaxFileUpload which have the functionality drag and drop, at page load the upload control is working fine but after the first trigger on the update panel the control stops working.
Thanks in advance.
I was able to replicate the issue and solve it by placing the AjaxFileUpload control inside of the ContentTemplate node of an UpdatePanel.
If you place it in its own UpdatePanel, make sure the UpdateMode is set to "Always". If you want it to be "Conditional", you'll need to have it be updated with the trigger in some way.
<asp:UpdatePanel ID="UpdatePanel2" runat="server" UpdateMode="Always">
<ContentTemplate>
<ajaxToolkit:AjaxFileUpload ID="AjaxFileUpload2" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
I have a user control placed inside an update panel, ie like this.
<asp:UpdatePanel ID="testupdatepnl" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<uc1:TestControl ID="ctlTest" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
Now i got a button placed inside this user control say Click. I want to postback the whole page on the button click.
I tried to add a postback trigger like this
<Triggers>
<asp:PostBackTrigger ControlID="clickButton" />
</Triggers>
Since the button is inside the usercontrol , i got error while running like this.
Is there any way to do a postback for this button.
Remove the <Triggers> from HTML & Add this to PageLoad event
ScriptManager scriptManager = ScriptManager.GetCurrent(this.Page);
scriptManager.RegisterPostBackControl(WebUserControl11.FindControl("ButtonId"));
Note : Learned from this
Because button you are using as trigger is placed inside update panel and after render its client id gets changed.
Make the button accessable from user control and declare the trigger at server side e.g.
var ClickButton= ctlTest.FindControl("clickButton") as Button;
var trigger = new PostBackTrigger();
trigger.ControlID = ClickButton.UniqueID.ToString();
testupdatepnl.Triggers.Add(trigger);
See the following thread for more details
Trigger a button inside a UpdatePanel with a LoginView
You should also note that if you are using Ajax Control Toolkit. You can replace ScriptManager to ToolkitScriptManager.
Dim btn As Button = CType(UserControl.FindControl("ButtonID"), Button)
AjaxControlToolkit.ToolkitScriptManager.GetCurrent(Page).RegisterPostBackControl(btn)
I have an UpdatePanel with some checkboxes in it. I check them, and hit my Save button, but that causes the UpdatePanel to postback (refresh) and sets them all back to blank. The re-drawing method runs before the button code.
What is the correct way to have an UpdatePanel with checkboxes in that you can manipulate?
Example of code:
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="updatePanel1">
<ContentTemplate>
<asp:CheckBox runat="server" ID="myCheckBox" Caption="CheckBox"/>
<asp:Button runat="server" ID="saveButton"
Caption="Save" OnClick="SaveButtonClick"/>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="saveButton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
Make sure that:
UpdateMode of UpdatePanel is Conditional
SaveButton contained in Triggers-section as ControlID of AsyncPostBackTrigger
Your code behind should look like:
if(!page.ispostback)
{
re-drawing();
}
As when you hit Save button your re-drawing() method is called and it again refreshes your checkboxes. Asynchronous postback behaves and hit to page method the same as full postback, but refreshes the values in any updatepanels.
Also check this URL
http://ajax.net-tutorials.com/controls/updatepanel-control/
Make sure the Save button is inside the Update Panel, for a start, and if not, that is designated as a Trigger for the Update Panel, in the <Triggers> section of the Update Panel.
<asp:UpdatePanel ID="MyControlPanel" runat="server" UpdateMode="Conditional">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="SaveButton" />
</Triggers>
<ContentTemplate> ...
Can you show some code for your UpdatePanel?
If you use server controls to render checkboxes you should add EnableViewState="true" attribute to these controls and update panel.
If you have checkboxes that are not server controls, then remove them from update panel, include only server controls inside. This leads to keeping several updates panel on a page that's usually not a big issue.
Add a ScriptManager object to your page if you do not have one. Set EnablePartialRendering="true". Put your UpdatePanel anywhere else on the page and place the content you want ajaxified within a tag within your UpdatePanel.