Lost listview datasource when button clicked - asp.net

I have radlistview. I add datasource to listview when page_load. But when I clicked I button in same page. I lost datasource of listview. Why? how can I fix it?


Try putting your listview databinding code inside something like this.
protected void Page_Load(object sender, EventArgs e)
{
if(!IsPostBack)
{
myListview.DataSource = myDatasource;
myListView.DataBind();
}
}
You may also want to consider using UpdatePanels if you wanting to only postback a part of the page, rather than the whole page.


I found the solution. I added EnableViewState="true" property and problem fixed. Like this
<telerik:RadListView ID="lvDSTableSelection" runat="server" AllowMultiItemSelection="true" OnSelectedIndexChanged="lvDSTableSelection_SelectedIndexChanged" EnableViewState="true" >

Related

Button click not firing in UserControl

I have user control deriving from BaseUserControl class and Now I need to add button in UserControl file(ascx)
I have added following code snippet in ascx:
<asp:Button ID="btnSubmit" runat="server" Text="Submit" OnClick="btnSubmit_Click"/>
Below is the code sample of ascx.cs file
public partial class MyContol : BaseUserControl
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
// code to execute after button is clicked
}
}
But here the button event is not triggering and during debug I am able to see its hitting Page_Load event, please help me to resolve on this.
Regards
Anand

I have seen this type of thing many times. Try the following.
Remove the button from the ASCX side of the page.
Remove the C# btn submit method.
Save the page.
Now go into design view...
Add the button back, assign the name in design view.
In Design View double click on the button so that it created the C# method for you.

Ajaxfileupload not working when dropdownlist is place inside an updatepanel in ASP.NET

When the page is loaded I have no problem using the ajaxfileupload and selecting files for the upload.
This works perfectly until I select a value of the first dropdownlist and the second dropdownlist inside the updatepanel gets populated via the partial postback. From this event on, the select button of the ajaxfileupload control is without function.
Is this a bug or how to overcome this issue?

set the dropdown's ID in PostBackTrigger of the update panel.
update:
<UpdatePanel ID="upd1">
<asp:DropDownList ID="ddl1" onselectedIndexChanged="ddl_changed" />
</UpdatePanel>
<UpdatePanel ID="upd2">
<Ajax:FileUploader />
</UpdatePanel>
protected void ddl1_changed(object sender, EventArgs e)
{
//your code
upd2.Update();
}
This might help you :)

Click on an 'image button' in a repeater in asp.net

I have a repeater and there is an image button in each row of this.
By clicking on each Image button ,I should get the Id of respective row but I don't Know how to manage the click event of this image button in repeater.

Try this:
ASPX
<asp:LinkButton OnCommand="lbRemove_Command" CommandArgument='<%# Eval("Key")%>' CommandName="Remove" runat="server">
Code Behind
protected void lbRemove_Command(object sender, CommandEventArgs e)
{
switch (e.CommandName)
{
case "Remove":
string ca = e.CommandArgument.ToString();
break;
}
}

You need to use ItemCommand event of repeater. You may also look in to ItemDataBound for custom actions on while binding data source.

asp.net 3.5 Treeview Empty after Postback

I have an asp.net page which has a web control.
This web control displays a Treeview, TextBox and a button.
For the treeview i do on Page_Load:
if (!Page.IsPostBack) {
BindTreeView();
}
This is my TreeView definition:
<asp:TreeView ID="TvwData" runat="server"
BackColor="White" ShowCheckBoxes="Leaf" Width="99%"
ExpandDepth="3" AutoGenerateDataBindings="false"
onselectednodechanged="TvwData_SelectedNodeChanged"
EnableViewState="true"
>
The TreeView is shown correctly.
However, when I click the submit button, the following happens:
Page reloads, textbox still displays my text which is OK.
My Treeview doesn't display any data at all.
When debugging, TvwData.CheckedNodes doesn't contain any data while I'm sure there are treeview items checked.
I really tried my best to found a solution on major ASP.NET forums, but I'm clueless at this moment.
Thanks in advance!

Try the following:
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
BindTreeView();
}
Furthermore, remove BindTreeView(); from Page_Load.

ASP.Net repeater Item Command not getting fired

OK, I've used repeaters literally hundreds of times without problems but something has gone awry today. I have a repeater and I'm subscribing to the itemCommand event, but when my command runs, the page posts back but the event isn't fired.
To get around this I'm having to do my databinding on each postback.
My repeater looks like this:
<asp:Repeater id="MyRepeater" runat="server" onitemcommand="MyRepeater_ItemCommand">
<ItemTemplate>
<li>
<asp:Label id="Label" runat="server" />
<asp:LinkButton id="LinkButton1" runat="server" commandname="Complete" commandargument='<%# Eval("MyID") %>' text='<%# Eval("Title") %>' />
</li>
</ItemTemplate>
</asp:Repeater>
and my codebehind like this:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
SetupPage();
}
}
private void SetupPage()
{
// Do other stuff
MyRepeater.DataSource = Repository.GetStuff()
MyRepeater.DataBind();
}
protected void MyRepeater_ItemCommand(object sender, RepeaterCommandEventArgs e)
{
// Do all my stuff here
}
MyRepeater_ItemCommand is not getting called unless I comment out the if (!IsPostBack) line. Once that is commented out and the repeater is getting databound on each postback it works OK. I've done this in so many other pages but on this on it just doesn't seem to work.
Anyone else come across this behaviour or have a solution?

Most likely, you have disabled ViewState for the page.
The reason is that when you execute the postback, all the controls in the repeater are rebuild from the data in the viewstate normally. Then the object that should receive the event is identified based on the ID of the control, and the event is routed.
If you disable the viewstate, the control tree is not rebuild during postback, and therefore the control that should receive the event does not exist in memory. So the event dies.
If you really want to disable the viewstate, but still want to receive the event, I have a workaround (and it's not dirty at all). I've long been thinking about writing a blog entry about it, so if you want, I can take a bit time off my normal chores, and describe it.
Edit: The workaround is described here: http://petesdotnet.blogspot.dk/2009/08/asp.html

Remove if (!IsPostBack) as this is preventing the repeater from rebinding,
and the item command event could not find the row after postback.

I have the same problem and aside from using update panel, I have a required field validator in my modal. I found out that the LinkButtons in my repeater triggers the requiredFieldValidor event and then I added CausesValidation="false" in the LinkButtons of my repeater. Works as expected.

I have this problem in a repeater when I use ImageButton ...
I have search the net for this solution when LinkButton work, but not ImageButton ...
Then I think, LinkButton work? so i will use it :)
<asp:LinkButton CommandName="Filter" CommandArgument='<%# Eval("ID") %>' Text="" runat="server" >
<asp:image imageurl='<%#Eval("Img") %>' runat="server"/>
</asp:LinkButton>
So, the image is inside the <A> tag
have fun :)

I removed PostBackUrl property in linkbutton and ItemCommand fired. I think postback runs first.

That may be you have set Validations on your page. So set an new attribute, causevaliation = "false" to Link button. M sure it will solve the problem

I had a similar issue - turned out some discreet validation controls were firing elsewhere on the page. It only took me a day to figure it out ...

I am not positive about this, but you might have to set the CommandName and optionally CommandArgument properties for the button causing the ItemCommand event. Otherwise ASP.NET would assume that there is no button on the page, which you'd like to fire the event. You can try that.
Plus, if you're not differentiating between command names, why not use each button's Click event instead? Just subscribe to those in the repeater's ItemCreated or ItemDataBound.

Try using Page_init instead of Page_load and that should fix the problem.

Try this:
protected void Page_Load(object sender, EventArgs e)
{
SetupPage();
}
If you use nested-repeater, you should rebind your inner repe

Here Is the code you have to use in code behind..
after PageLoad event,
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Page_LoadComplete(object sender, EventArgs e)
{
// Bind Your Repeater here
rptUser();
}
now you can fire your Itemcommand..if you get Output please mark answer as right thanks

One other thing that it could be (as it just happened to me): if your databind takes place when your page is prerendered, it won't process the item command. Switch it to load or init and you'll be fine.

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