So, I have an event that is fired always when a text file is updated. This is the event handler:
private void FileWasChanged()
{
this.runsList.Items.Clear();
runningModels = RunsFile.ReadFile(Constants.active_runs_loc, Constants.run_file_name);
this.runsList.DataSource = runningModels;
this.runsList.DataBind();
this.updatePanel.Update();
}
Within this method I am clearing the ListView (runsList), reading the contents of the file and then binding the new data to the ListView. The updatepanel is then updated. But that does not happen, the page stays static until I press F5. Here's the layout:
<section>
<asp:ScriptManager ID="scriptManager1" runat="server" ></asp:ScriptManager>
<asp:UpdatePanel id="updatePanel" UpdateMode="Conditional" runat="server">
<ContentTemplate>
<asp:ListView ID="runsList" runat="server">
<LayoutTemplate>
<ul>
<asp:PlaceHolder ID="itemPlaceholder" runat="server" />
</ul>
</LayoutTemplate>
<ItemTemplate>
<li>
<asp:Label Text="<%# Container.DataItem %>" runat="server" />
</li>
</ItemTemplate>
</asp:ListView>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger controlid="runsList"/>
</Triggers>
</asp:UpdatePanel>
</section>
So I am trying to give the user of the web site real time information from the text file. For example, when I change a line in the text file, that line should be added to the web page. The event itself works fine (tested with break points and console project), but for some reason the async update does not do anything.
I tried to look for similar problems, but everyone is using a button for the asyncpostbacktrigger. However, I am very new to C# so I may be misunderstanding how UpdatePanel and ListView DataBind work.
Any help appreciated!
Cheers,
Tetsii
Edit: The FileWasChanged is a handler that is called from FileSystemWatcher OnChanged event. The handler updates the view if called from Page_Load or an async button trigger.
Related
ASP.NET radio button is not visible in my page. I am using it inside ASP.NET ListView. I tried putting the radio button inside ASP.NET update panel content template as well. Please tell me what has gone wrong?
<asp:UpdatePanel runat="server">
<ContentTemplate>
<asp:ListView ID="FraudCheckList_listView" runat="server">
<ItemTemplate>
<p class="fraud-step-title"><%#Eval("question")%></p>
<div class="row">
<asp:RadioButton
runat="server"
class="radio-inline col"
GroupName="govt"
Text="Low Risk"
></asp:RadioButton>
<asp:RadioButton
runat="server"
GroupName='govt'
Text="Medium Risk"
></asp:RadioButton>
<asp:RadioButton
runat="server"
GroupName='govt'
Text="High Risk"
></asp:RadioButton>
</div>
</ItemTemplate>
</asp:ListView>
</ContentTemplate>
</asp:UpdatePanel>
Since you haven't shared how your code looks like, i am just assuming certain things. Just see if you have done this or not.
void Button_Click(object sender, System.EventArgs e){RadioButton.Visible=false;}
If incase its true or something your radiobutton will not be visible. In your case it must be hidden. So, make the variable of visible as **false ** So you can just change your code to this and try it out.
This you have to do it in your main code. not in your html code.
Thank You!
I have a Listbox that exists in an UpdatePanel on an ASP.NET webform. Also inside the UpdatePanel, exists a Button that adds a bunch of ListItem's to the Listbox, this PostBackTrigger as shown below:
<asp:UpdatePanel ID="updSection6" runat="server">
<ContentTemplate>
<asp:LinkButton Text="Run Scan" ID="btnEditSectionStory6" runat="server" OnClick="btnRunScan_Click" />
<br />
<asp:ListBox ID="lbLog" runat="server" Height="263px" Width="747px"></asp:ListBox>
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="btnEditSectionStory6" />
</Triggers>
</asp:UpdatePanel>
I add items in the click event:
protected void btnRunScan_Click(object sender, EventArgs e)
{
lbLog.Items.Add("Scan Beginning...");
.....hundreds of other items
}
The items are added to the ListBox, however it is after the entire btnRunScan_Click method is run, rather than adding them as each event occurs (So the user can receive messages as the actions occur). Am I missing an attribute or something on the UpdatePanel?
TIA
To Add Items without refreshing page or prevent from calling the cyclic events use following code and eliminate postBackTrigger inside the Trigger.Use following code that is tested working for me.Also use the scriptManager to prevent from exception over to use the updatePanel
.aspx design file
<asp:ScriptManager runat="server"></asp:ScriptManager>
<asp:UpdatePanel ID="updSection6" runat="server">
<Triggers>
</Triggers>
<ContentTemplate>
<asp:LinkButton Text="Run Scan" ID="btnEditSectionStory6" runat="server" OnClick="btnRunScan_Click" />
<br />
<asp:ListBox ID="lbLog" runat="server" Height="263px" Width="747px"></asp:ListBox>
</ContentTemplate>
</asp:UpdatePanel>
.cs file
protected void btnRunScan_Click(object sender, EventArgs e)
{
lbLog.Items.Add("Scan Beginning...");
}
As other also mention you can also use jquery with ajax to code over the client side to do this one.
Basically I have this situation
Page >
Update Panel >
User Control >
List View >
User Control (Within item template) >
Update Panel
When I click on a button within the inner most update panel, I want the content of the update panel to update. This isn't happening. However, the click handler is being hit fine asynchronously. The update panel just doesn't want to update.
Code - I've created a simple test web app that replicates the problem, and shared it on my google drive: UpdatePanelInListViewTest.zip, but here's the markup:
Page:
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="ajaxParent" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<uc1:ListUserControl ID="ListUserControl1" runat="server" />
</ContentTemplate>
</asp:UpdatePanel>
List User Control:
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="ListUserControl.ascx.cs" Inherits="UpdatePanelInListViewTest.ListUserControl" %>
<%# Register src="MiniWidget.ascx" tagname="MiniWidget" tagprefix="uc1" %>
<asp:ListView ID="lstTest" runat="server">
<ItemTemplate>
Item
<uc1:MiniWidget ID="MiniWidget1" runat="server" />
</ItemTemplate>
</asp:ListView>
Mini Widget User Control
<%# Control Language="C#" AutoEventWireup="true" CodeBehind="MiniWidget.ascx.cs" Inherits="UpdatePanelInListViewTest.MiniWidget" %>
<asp:UpdatePanel ID="ajaxWidget" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:LinkButton ID="lnkTest" runat="server" onclick="lnkTest_Click">Test</asp:LinkButton>
<asp:Label ID="lblTest" runat="server" Text=""></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
I've tried different permutations of this; i.e. having the button outside the panel and adding a trigger etc but I just cannot get it to update.
It appears that because the user control is within an item template of the parent list view it causes the update panel to not update for some reason...
The problem is to do with when you call the databind method within ListUserControl.
Moving lstTest.DataBind(); so that it executes within the Page_Load rather than the Page_PreRender fixes the issue for your simple test web app.
have u tried:
<asp:UpdatePanel ID="ajaxPanel" runat="server" ChildrenAsTriggers="true" UpdateMode="Conditional">
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnTest" />
</Triggers>
<ContentTemplate>
<asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
<asp:Button ID="btnTest" runat="server" Text="Test" onclick="btnTest_Click" />
</ContentTemplate>
</asp:UpdatePanel>
I have an update panel that has UpdateMode of Conditional and ChildrenAsTriggers set to false. I only want a few controls to cause an asynchronous postback:
<asp:UpdatePanel ID="updPnlMain" runat="server" UpdateMode="Conditional" ChildrenAsTriggers="false">
<ContentTemplate>
// ...
<asp:Repeater ID="rptListData" runat="server">
<ItemTemplate>
<asp:Button ID="btnAddSomething" runat="server" OnClick="btnAddSomething_Click" />
</ItemTemplate>
</asp:Repeater>
// ...
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnAddSomething" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
I am getting the following error when I try and load this page:
A control with ID 'btnAddSomething' could not be found for the trigger in UpdatePanel 'updPnlMain'.
Since my btnAddSomething control is in a repeater and might not be there right away it acts like it is nonexistent. How can I get around this?
Because your control is in the repeater control and it is out of scope to the Trigger collection. By the way you don't need to add trigger because your button control is already in the UpdatePanel, it will update when you click the button.
Edit: There is a solution if you really want to update your updPnlMain updatepanel. You can put in another updatepanel and put your button in that panel. e.g.
<asp:UpdatePanel ID="updButton" runat="server" UpdateMode="Conditional">
<asp:Button ID="btnAddSomething" runat="server" OnClick="btnAddSomething_Click" />
</ContentTemplate>
and then simply call the updPnlMain.Update(); method in btnAddSomething_Click event.
It will actually do what you are looking for :)
My content page
<asp:updatePanel id="Panel1" runat="server" Visible="true">
<ContentTemplate>
<div>
blah blah
</div>
</ContentTemplate>
</asp:updatePanel>
<asp:updatePanel id="Panel2" runat="server" Visible="false">
<ContentTemplate>
<div>
yada yada
</div>
</ContentTemplate>
</asp:updatePanel>
Code file ..The following code is at the end of Submit button click event :-
Panel1.Visible = false;
Panel2.Visible = true;
Now earlier I was using asp:Panel..then it was working fine..like Panel 1 would hide and Panel 2 would show up instead..it was AFTER I changed asp:Panel to asp:updatePanel that things got screwed up...now the Submit button just won't work !!
What's gone wrong suddenly ?? I changed it to updatePanel so the page doesn't refresh..isn't this how we implement this thing ???
<asp:updatePanel id="Panel1" runat="server">
<ContentTemplate>
<div>
<p>
Type ur name
<asp:TextBox ID="name" runat="server">
</asp:TextBox>
</p>
<asp:Button ID="btn" OnClick="btn_Click" runat="server"
Text="Submit" />
</div>
</ContentTemplate>
</asp:updatePanel>
<asp:updatePanel id="Panel2" runat="server" Visible="false">
<ContentTemplate>
<div>
Thank You!
</div>
</ContentTemplate>
</asp:updatePanel>
At http://msdn.microsoft.com/en-us/magazine/cc163413.aspx#S3 , you can read
Multiple UpdatePanels
A page can host several UpdatePanels. By default, when one UpdatePanel on a page updates, the other UpdatePanels on the page also update. Sometimes that’s what you want, but more often than not, you don’t need every UpdatePanel updating in response to other UpdatePanels.
You can be selective about which UpdatePanel instances update (and when) by setting the UpdateMode property of each UpdatePanel control on the page to "Conditional." Then, when one UpdatePanel updates and calls a server-side event handler, call UpdatePanel.Update on the other panels you want to update. This reduces the load on the server by reducing the number of controls that render, and it reduces the volume of data in the response because UpdatePanels that don’t update don’t add anything to the response.
If you set Visible="false" on an UpdatePanel, it won't be rendered to the client at all. Therefore, if you're doing an Ajax postback, the client isn't going to be able to make the invisible UpdatePanel visible, because it just isn't there.
Think of UpdatePanels just as markers, showing which bits of your page you want to update on an Ajax postback. For your scenario, I think the easiest solution would be to use both UpdatePanels and Panels. Also, because the two things you're updating (the two Panels) are right next to each other, there's no need for two separate UpdatePanels:
<asp:updatePanel id="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Panel id="Panel1" Visible="true" runat="server">
blah blah
</asp:Panel>
<asp:Panel id="Panel2" Visible="false" runat="server">
yada yada
</asp:Panel>
</ContentTemplate>
</asp:updatePanel>
Then in the code-behind, change the Visible property on the Panel controls.
I do not know where your Submit button is, but maybe try updating those panels with:
Panel1.Update();
Panel2.Update();