Refreshing only the update with values from drop down box - c#

I have a drop down list named "DropDownList1". Any value picked from the drop down list must not refresh the page, but only refresh the panel My code is as follows.
<asp:DropDownList ID="DropDownList1" runat="server" Width="200px" autopostback="true" OnSelectedIndexChanged="DropDownList1sel">
<asp:ListItem Text="abc" Value="0"></asp:ListItem>
<asp:ListItem Text="a" Value="1"></asp:ListItem>
<asp:ListItem Text="b" Value="2"></asp:ListItem>
<asp:ListItem Text="c" Value="3"></asp:ListItem>
</asp:DropDownList>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:Label ID="Label1" runat="server" Text=""></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
When i run this code, it must call the function named "DropDownList1sel" in the ascx.cs where "Label1" is populated. Now the page is refreshed and the values are populated. I want to have the panel refreshed without the page being reloaded. Please help.


Few things to do
Set UpdateMode=conditional then add Trigger as DropDownList1
<asp:UpdatePanel ID="UpdatePanel1" UpdateMode="conditional" runat="server">
<ContentTemplate>
<asp:Label ID="Label1" runat="server" Text=""></asp:Label>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="DropDownList1"
EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>


Why not add the DropDown inside your UpdatePanel.
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server" Width="200px"
AutoPostBack="true" OnSelectedIndexChanged="DropDownList1_OnSelectedIndexChanged">
<asp:ListItem Text="abc" Value="0"></asp:ListItem>
<asp:ListItem Text="a" Value="1"></asp:ListItem>
<asp:ListItem Text="b" Value="2"></asp:ListItem>
<asp:ListItem Text="c" Value="3"></asp:ListItem>
</asp:DropDownList>
<asp:Label ID="Label1" runat="server" Text=""></asp:Label>
</ContentTemplate>
<Triggers>
<asp:PostBackTrigger ControlID="DropDownList1"/>
</Triggers>
</asp:UpdatePanel>


You must place that panel inside an update panel..
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<panel id="panel1">
</panel>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="DropDownList1" />
</Triggers>
</asp:UpdatePanel>

Related

How to use update panel in datagrid

Below is the code which i have applied, it is giving me a error.
<asp:TemplateColumn>
<HeaderTemplate >
<label>Article</label>
</HeaderTemplate>
<ItemTemplate>
<asp:DropDownList ID="DrpArticle" runat="server" TabIndex="4" CssClass="form-control" AutoPostBack="true"
OnSelectedIndexChanged = "DrpArticle_SelectedIndexChanged" AppendDataBoundItems = "true">
</asp:DropDownList>
<asp:UpdatePanel runat="server" ID="UpdatePanel1" UpdateMode="Conditional">
<Triggers><asp:AsyncPostBackTrigger ControlID="DrpArticle" EventName="OnSelectedIndexChanged" /></Triggers>
<ContentTemplate>
<asp:Label ID="LblStock" runat="server" Text="..." ForeColor="#000066"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
</ItemTemplate>
</asp:TemplateColumn>

ID not found even already declared C# ASP Update Panel Click Trigger

A control with ID 'contactButton' could not be found for the trigger in UpdatePanel 'contactUpdatePanel'.
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" />
<asp:UpdatePanel ID="contactUpdatePanel" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:ListView ID="contactList" runat="server">
<ItemTemplate>
<asp:Panel runat="server">
<asp:Label ID="contactLabel" runat="server" Text='<%# Bind("Number") %>' ></asp:Label>
<asp:Button OnClick="contactButton_Click" ID="contactButton" runat="server" Text="Assign"/>
</asp:Panel>
</ItemTemplate>
</asp:ListView>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="contactButton" EventName="Click" />
</Triggers>
</asp:UpdatePanel>

Just remove this line because Listview and button are not outside the update panel so it will work automatically.
<Triggers>
<asp:AsyncPostBackTrigger ControlID="contactButton" EventName="Click" />
</Triggers>
Your final code
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" />
<asp:UpdatePanel ID="contactUpdatePanel" runat="server" UpdateMode="Always">
<ContentTemplate>
<asp:ListView ID="contactList" runat="server">
<ItemTemplate>
<asp:Panel runat="server">
<asp:Label ID="contactLabel" runat="server" Text='<%# Bind("Number") %>' ></asp:Label>
<asp:Button OnClick="contactButton_Click" ID="contactButton" runat="server" Text="Assign"/>
</asp:Panel>
</ItemTemplate>
</asp:ListView>
</ContentTemplate>
</asp:UpdatePanel>

ASPX event not firing

I just want to ask what's the problem in my codes here? The OnSelectedIndexChanged event in #cbList is working fine but the ondrop event in #sortable2 is not working. I tried placing it inside and outside the update panel. The code that is being called in the ondrop is in code behind. It just change the dummyText's text.
Here's my code:
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server" ChildrenAsTriggers="true">
<ContentTemplate>
<input type="hidden" runat="server" id="hdnSelectedValue" />
<asp:CheckBoxList ID="cbList" runat="server" AutoPostBack="true" OnSelectedIndexChanged="cbList_SelectedIndexChanged">
<asp:ListItem Text="One" Value="1">
</asp:ListItem>
<asp:ListItem Text="Two" Value="2">
</asp:ListItem>
<asp:ListItem Text="Three" Value="3">
</asp:ListItem>
<asp:ListItem Text="Four" Value="4">
</asp:ListItem>
<asp:ListItem Text="Five" Value="5">
</asp:ListItem>
</asp:CheckBoxList>
<br />
<asp:Label ID="lblSelection" runat="server"></asp:Label>
<asp:Label ID="dummyText" runat="server" Text="Here"></asp:Label>
<ul id="sortable2" runat="server" class="connectedSortable" ondrop="Change_Text"></ul>
</ContentTemplate>
</asp:UpdatePanel>
</form>

ondrop="" is client side event. You cannot wired up this event in code behind.
Check this link for more information on OnDrop event

UpdatePanel Trigger Error. Could not find an event on associated control for the trigger in UpdatePanel

I am having trouble with asp:UpdatePanel and Trigger of ASP.NET WebForms. Trigger could not find the event on my UpdatePanel. I've seen a lot of examples and I copied their implementations but could not get it right. I'm totally new in WebForms. Please help. Thank you.
<tr>
<td class="label1">Will use ETL?</td>
<td>
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="updatePanel1">
<ContentTemplate>
<asp:RadioButtonList ID="useEtl" runat="server" RepeatDirection="Horizontal" Width="120" OnSelectedIndexChanged="useEtl_SelectedIndexChanged">
<asp:ListItem Text="Yes" Value="1" />
<asp:ListItem Text="No" Value="0" />
</asp:RadioButtonList>
</ContentTemplate>
</asp:UpdatePanel>
</td>
<td class="label1">ETL Box</td>
<td>
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="updatePanel2">
<ContentTemplate>
<asp:TextBox ID="etlBox" runat="server"/>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="useEtl" EventName="OnSelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
</td>
</tr>

change your code as follows:
<asp:AsyncPostBackTrigger ControlID="useEtl" EventName="SelectedIndexChanged" />
the event name you mentioned was wrong that's the reason for not working.
you can also try the following code for the same
UpdatePanel1.Triggers.Add(new AsyncPostBackTrigger()
{
ControlID = useEtl,
EventName = "SelectedIndexChanged", // this may be optional
}

td>
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="updatePanel1">
<ContentTemplate>
<asp:RadioButtonList ID="useEtl" runat="server" RepeatDirection="Horizontal" AutoPostBack="true" Width="120" OnSelectedIndexChanged="useEtl_SelectedIndexChanged">
<asp:ListItem Text="Yes" Value="1" />
<asp:ListItem Text="No" Value="0" />
</asp:RadioButtonList>
</ContentTemplate>
</asp:UpdatePanel>
</td>
<td class="label1">ETL Box</td>
<td>
<asp:UpdatePanel runat="server" UpdateMode="Conditional" ID="updatePanel2">
<ContentTemplate>
<asp:TextBox ID="etlBox" runat="server" Enabled="false"/>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="useEtl" EventName="SelectedIndexChanged" />
</Triggers>
</asp:UpdatePanel>
</td>

when I use the DropDownList1_SelectedIndexChanged to be the trigger of UpDatePanel，it dosn't work

And the tip is the “DropDownList1” didn't find “DropDownList1_SelectedIndexChanged”
</asp:ScriptManager>
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:DropDownList ID="DropDownList1" runat="server"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">
<asp:ListItem>1</asp:ListItem>
</asp:DropDownList>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="DropDownList1" EventName="DropDownList1_SelectedIndexChanged" />
</Triggers>
Please tell me How to make it work!

you need AutoPostBack=True
<asp:DropDownList ID="DropDownList1" runat="server" AutoPostBack="True"
onselectedindexchanged="DropDownList1_SelectedIndexChanged">

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