I'm having a FileUpload control on a aspx page inside a UpdatePanel with a button on click of which I want to set a label with the filename of the selected file.
Here is the code I have:
ASPX PAGE:
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:FileUpload runat="server" ID="fuSimple"></asp:FileUpload>
<asp:Button runat="server" Text="Button" ID="btnPostback"
onclick="btnPostback_Click" />
<br />
<asp:Label ID="lblFileName" runat="server" Text="File Name: "></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
</div>
Code Behind:
protected void btnPostback_Click(object sender, EventArgs e)
{
lblFileName.Text = "File Name: " + fuSimple.FileName;
}
Every time I hit the button, I'm getting an empty string. What am I missing?
Also, when I do this without UpdatePanel it works fine.
Comments/help appreciated.
The FileUpload control is not supported with ASP.NET AJAX and Asynchronous Postbacks. They require a full postback due to the nature of how a file upload works (multipart form data).
The following question should have useful answers: FileUpload control inside an UpdatePanel without refreshing the whole page?
Related
I am working on a C# asp.net web forms project. It has two master pages. I
have an user control which reads data from database,
creates an un-ordered list in html string and populates a placeholder with
it. This user control has to be automatically
refreshed every 2 minutes. I have included this usercontrol on the parent
master page. I have the following code to refresh the
user control, which I have obtained through another stackoverflow answer.
The problem is that the entire master page refreshes, and I am not sure why.
Is there a way to make that only the user control which has the UpdatePanel
refreshes?
Outer Master Page:
<body>
<form id="frmMain" role="form" method="post" runat="server">
<div>
<uc2:PendingOrders runat="server" ID="PendingOrders" />
</div>
<asp:ContentPlaceHolder ID="MainBodyContent" runat="server">
</asp:ContentPlaceHolder>
</form>
</body>
User Control:
<asp:ScriptManager ID="myScriptManager" runat="server"
EnablePartialRendering="True"></asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" UpdateMode = "Conditional"
runat="server">
<ContentTemplate>
<asp:Timer ID="Timer1" runat="server" Interval="20000"
OnTick="Timer1_Tick"></asp:Timer>
<asp:PlaceHolder runat="server" id="lblMyOrders"></asp:PlaceHolder>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="Timer1" EventName="Tick" />
</Triggers>
</asp:UpdatePanel>
User Control Code behind:
protected void Timer1_Tick(object sender, EventArgs e)
{
//This method creates the html string with data as an unordered list
and
//populates asp:PlaceHolder inte updatepanel
GetData();
}
UpdatePanel1's Content will be update by Timer1_Tick.
"entire master page refreshes" means master page's Page_Load will be call while Timer1 been trigger?
UpdatePanel always post entire page back server and only render UpdatePanel1's Content.
I had the same problem, but in our project the EnablePartialRendering was set to false on the Master Page, if set to true the whole project breaks.
To fix the problem, I defined another master page without ScriptManager and added the ScriptManager to the page in which I wanted to use UpdatePanels with the EnablePartialRendering attribute set to True.
This fixed the problem.
<asp:ScriptManager ID="myScriptManager" runat="server" EnablePartialRendering="True"></asp:ScriptManager>
I'm a newbie to ASP.net (vb), and i'm working with the timer controls. I've once again researched the answer to this and done as said (overloading prerender method). My problem is I have a master page which i've added a timer control, in order to update a count down field, on going to the sites index page i keep getting the error : "Script controls may not be registered before PreRender." The timer works well on other pages except the index page.
<form id="fMain" runat="server">
<div>
<asp:ScriptManager ID="ScriptManager1" runat="server"></asp:ScriptManager>
<asp:Timer ID="timer1" runat="server" Interval="1000" OnTick="timer1_tick"></asp:Timer></div>
<div>
<asp:UpdatePanel id="updPnl" runat="server" UpdateMode="Conditional">
<ContentTemplate>
<asp:Literal ID="litTimer" runat="server"></asp:Literal>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="timer1" EventName ="tick" />
</Triggers>
</asp:UpdatePanel>
</div>
The Codebehind:
Sub timer1_tick() Handles timer1.Tick
ltr1.text = "test"
End Sub`
Thank you in advance.
This is because you are using Telerik controls and have overridden the OnPreRender method.
You need to add the following to this method:
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
I have this code in form:
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:TextBox ID="Text1" runat="server"></asp:TextBox>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:TextBox ID="Text2" runat="server"></asp:TextBox>
<asp:Button ID="Submit" runat="server" OnClick="Submit_Click"
Text="Click Me"/>
</ContentTemplate>
</asp:UpdatePanel>
When I click on Submit button, the all form is posted back on server (Text1 and Text2). I want to post back only textbox in UpdatePanel (Text2). Is it possible?
Thank you for responses.
EDIT (Solution):
I think, I have solution using Javascript:
function onSubmit() {
var text1 = this.document.getElementById('<%=Text1.ClientID%>');
text1.disabled = true;
return true;
}
....
<asp:Button ID="Submit" OnClientClick="onSubmit();" ..../>
It cause that Text1 will be disabled before PostBack. It seams that ASP.NET do not post back values from disabled textboxes. Hovewer, this works only without UpdatePanel. Of course, Text1 is empty after postback.
Well, the UpdatePanel controls what get's posted back. You cannot change that behavior. It should be posting the form data for the UpdatePanel only (I believe), plus the entire ViewState. It has to post the entire ViewState for the page lifecycle to work.
I have a repeater with a RadioButtonList inside the ItemTemplate, but when the RadioButtonList.OnSelectedIndexChanged event fires it generates a full postback. What have I done wrong in my code below? How can I get the OnSelectedIndexChanged to generate an Async Postback?
<asp:UpdatePanel runat="server" ID="UpdatePanel2">
<ContentTemplate>
<asp:Repeater ID="Repeater1" runat="server" DataSourceID="sqlOptions">
<ItemTemplate>
<asp:UpdatePanel runat="server" ID="pnlA">
<ContentTemplate>
<strong>
<%# Eval("Name") %></strong><br />
<asp:RadioButtonList ID="RadioButtonList1"
DataSourceID="sqlOptionValues" runat="server"
DataTextField="id" DataValueField="Id" AutoPostBack="true"
OnSelectedIndexChanged="LoadPrice"
ValidationGroup="options" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1"
ForeColor="Red" runat="server"
ControlToValidate="RadioButtonList1"
ErrorMessage="Required Field"
ValidationGroup="options" />
<asp:SqlDataSource ID="sqlOptionValues" runat="server"
ConnectionString="<%$ ConnectionStrings:
ConnectionString6 %>"
SelectCommand='<%# "SELECT DISTINCT OptionValue.Name,
OptionValue.Id FROM CombinationDetail
INNER JOIN OptionValue
ON CombinationDetail.OptionValueId = OptionValue.Id
WHERE (OptionValue.OptionId =" +
Eval("Id") + ")" %>'>
</asp:SqlDataSource>
<br />
</ContentTemplate>
</asp:UpdatePanel>
</ItemTemplate>
</asp:Repeater>
</ContentTemplate>
</asp:UpdatePanel>
Many thanks for any help :)
This is a real-world use case. I have a page with Repeaters, Ajax Accordions inside of other Accordions, Update Panels inside other Update panels, you name it. The page works great, except when I want to update one of the Accordion panels with my RadioButtonList (RBL). Even with the RBL inside an update panel, it causes a postback of the entire page. I tried everything. I finally realized it wasn't me when I noticed my buttons would work just fine. I figure it must be a bug in either the framework or the Ajax Control Toolkit. I did find people reference this link all over the web (http://blog.smarx.com/posts/the-case-of-the-radiobuttonlist-half-trigger.aspx), but this link from 2007 is dead now and probably no longer applicable, so that's no help.
What I ended up doing was going with what works - that submit button. All I did was add an onclick attribute to the RBL to call a hidden button. Now you don't want to set the button to Visible=false because then the button won't appear in the generated markup. Instead, set the button's style to display:none; so that no one will see this hack, because yes, that's what this workaround is - it's a hack, but simple and just as effective as what you'd expect. Don't forget to remove the Autopostback="True" from your RBL.
CAVEAT: Because I'm using a hacked button for the onclick event, it's possible for the user to click in the area of the RBL, but not actually select an item. When this happens, our onclick triggers an AsyncPostBack and the codebehind logic will be processed, so please keep that in mind. To give you an idea of what I mean: all the Page_Load() events will be called, but rbl_Questions_SelectedIndexChanged() won't be if they happen to click in the area of the RBL without actually selecting an item. For my purposes this causes no issues in my logic and has no effect on the user.
Here's the Code:
Somewhere In the .Aspx Page:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:RadioButtonList ID="rbl_Questions" runat="server"
OnSelectedIndexChanged="rbl_Questions_SelectedIndexChanged">
</asp:RadioButtonList>
<asp:Button ID="btn_rbl_Questions" runat="server" style="display:none;"/>
<asp:Label ID="lbl_Result" runat="server" Text="" Visible="false">
</asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
In the Page_Load() event:
protected void Page_Load(object sender, EventArgs e)
{
if (IsPostBack == false)
{
//Instead of using the AutoPostback of the RBL, use this instead.
rbl_Questions.Attributes.Add("onclick",
"document.getElementById('"
+ btn_rbl_Questions.ClientID
+ "').click();");
//Bind your RBL to a DataSource, add items programmatically,
// or add them in the aspx markup.
}
}
In the rbl_Questions_SelectedIndexChanged() event:
protected void rbl_Questions_SelectedIndexChanged(object sender, EventArgs e)
{
//Your code here.
//My code unhid the lbl_Result control and set its text value.
}
Update 05/24/2011
The above "hack" is no longer necessary (I am leaving it above since this was marked as the answer by the author). I have found the best way to do this, thanks to this SO Answer:
Updatepanel gives full postback instead of asyncpostback
The code is much simpler now, just remove what I put in the Page_Load() method and remove the Button I used in the Aspx page and add ClientIDMode="AutoID" and AutoPostBack="True" to the control you want the UpdatePanel to capture.
Somewhere In the .Aspx Page:
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:RadioButtonList ID="rbl_Questions" runat="server"
ClientIDMode="AutoID" AutoPostBack="true"
OnSelectedIndexChanged="rbl_Questions_SelectedIndexChanged">
</asp:RadioButtonList>
<asp:Label ID="lbl_Result" runat="server" Text="" Visible="false">
</asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
MS changed how ClientID's are generated in .net 4.0 from "AutoID" to "Predictable" and I guess the ScriptManager or UpdatePanel's weren't updated correctly to use it. I can't find documentation on why that is anywhere or if it was left that way by design.
I seriously don't miss winforms.
Try this:
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="pnlA">
You'll also need to setup
<Triggers>
//radio buttons
</Triggers>
Not sure how you'll do that since it's a dynamically built list.
I'm trying to show message "Loading..." when a user select an item in the dorp down list.
Mark up:
<asp:Label ID="lbl_LoadingMessage" runat="server" ></asp:Label>
<asp:DropDownList ID="ddl_Chapter" runat="server" AutoPostBack="True">
</asp:DropDownList>
Code behind:
Protected Sub LoadMessage()
lblLoading.Text = "Loading..."
End Sub
Protected Sub ddl_Chapter_SelectedIndexChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles ddl_Chapter.SelectedIndexChanged
LoadMessage()
Dim redirectURL As String = "~/chapter.aspx?bid=" & BookId.ToString
Server.Transfer(redirectURL)
End Sub
The method I'm using above is not working. When I select a new item from the drop down list, it works as expected except the message "Loading..." is not showing at all. Any suggestion or code sample? Thank you.
You will have to do this on the client side using javascript.
At the moment, your dropdown menu is causing a postback. when the drop down menu is changed, the page post backs then the entire page life cycle is run through. When the event ddl_Chapter_SelectedIndexChanged is run, you set the text of the loading label, but you never reload the page (which would have your loading message) - instead you server.transfer to a new page.
If you use jQuery, you could set the labels text value as soon as the dropdown is changed
something like:
$('#the_full_renedered_ID_of_ddl_Chapter').change(function () {
$('#the_full_renedered_ID_of_lbl_LoadingMessage').html("Loading...")
});
Or use javascript:
<script type="text/javascript" src="http://jqueryjs.googlecode.com/files/jquery-1.3.2.min.js" /></script>
<script type="text/javascript">
$(document).ready( function() {
$("#<%= ddl_Chapter.ClientID %>").change(function()
{
window.alert("Loading");
});
});
</script>
The whole event will execute before the page re-rendering will take place.
If you are going to be doing extra processing between the LoadMessage() and the Server.Transfer try using AJAX UpdateProgress panel and adding your "loading..." message to that and add your dropDownList to a UpdatePanel.
This way depending on what code needs executing in your SelectedIndexChanged event it will show the "loading..." message before it via a partial page postback.
e.g
<asp:ScriptManager id="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdateProgress id="UpdateProgress1" runat="server" associatedUpdatePanelID="UpdatePanel1">
<ProgressTemplate>
<p>Loading....</p>
</ProgressTemplate>
</asp:UpdateProgress>
<asp:UpdatePanel id="UpdatePanel1" runat="server" childrenAsTriggers="true">
<ContentTemplate>
<asp:DropDownList id="DropDownList1" runat="server" autoPostBack="true">
<asp:ListItem selected="True" value="1">Book 1</asp:ListItem>
<asp:ListItem value="2">Book 2</asp:ListItem>
<asp:ListItem value="3">Book 3</asp:ListItem>
<asp:ListItem value="4">Book 4</asp:ListItem>
<asp:ListItem value="5">Book 5</asp:ListItem>
</asp:DropDownList>
<asp:Label id="lblSelected" runat="server"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
This way the "loading..." message will be displayed for the duration of the processing of what you are trying to achieve in your SelectedIndexChanged event. If this is simply for display reasons javaScript would be your best bet.