I've gone through many articles and question about this. But still not found the answer for my case.
The function handles event. It doesn't work at all
My code:
ASPX
<%# Page Language="C#" AutoEventWireup="true" CodeBehind="Popup.aspx.cs"
Inherits="GG.UI.Popup" %>
...
<asp:DropDownList ID="LEDropdown" runat="server" AutoPostBack="true"
OnSelectedIndexChanged="LEDropdown_Change" ></asp:DropDownList>
ASPX.CS
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
PopulateClist();
BindGrid();
}
}
protected void PopulateClist()
{
LEDropdown.Items.Clear();
LEDropdown.Items.Add(new ListItem("First Item", "First");
LEDropdown.Items.Add(new ListItem("Second Item", "Second");
LEDropdown.SelectedIndex = 0;
}
protected void LEDropdown_Change(object sender, EventArgs arg)
{
string selectedLE = ((DropDownList)(sender)).SelectedValue;
ClientScript.RegisterStartupScript(GetType(), "Alert", "alert('" + selectedLE + "');");
}
I tried using EnableViewState="true" for this page and the Masterpage as well.Didn't work.
The function LEDropdown_Change was never called.
The page is still posted back after selection.
There's another button with OnClick event and it works fine.
<asp:DropDownList ID="LEDropdown" runat="server" AutoPostBack="true" OnSelectedIndexChanged="LEDropdown_Change" ></asp:DropDownList>
Your dropdownlist is calling LEDropdown_Change
But your onchange event is called: LegalEntityDropdown_Change
Related
I've got an image button in a Repeater, which is in a User Control, and I can't get the OnItemCommand event to fire when I click it. It always gives the error: "... Invalid postback or callback argument. Event validation is enabled using ..."
When I change the image button to a link button, it doesn't give me the error, but it still doesn't fire the OnItemCommand function.
I found some other relevant answers (such as How to process events from Buttons inside Repeaters? And what's this EnableEventValidation thing?) but they all say, "Make sure you're data-binding your repeater inside of a if(!Page.IsPostBack) block." I have done that, but it didn't make a difference.
Here's the markup for the repeater:
<asp:Repeater ID="rptExpenses" OnItemDataBound="rptExpenses_ItemDataBound" OnItemCommand="Button_Command" runat="server" >
<ItemTemplate>
<asp:ImageButton ID="ibDelete" ImageUrl="~/Images/delete.png" CommandName="Delete" runat="server" />
</ItemTemplate>
</asp:Repeater>
Here's some exerpts from the code-behind
protected void Page_Load(object sender, EventArgs e) {
if (!IsPostBack) {
rptExpenses.DataSource = ExpenseIds;
rptExpenses.DataBind();
}
}
protected void rptExpenses_ItemDataBound(object sender, RepeaterItemEventArgs e) {
if ((e.Item.ItemType == ListItemType.Item) || (e.Item.ItemType == ListItemType.AlternatingItem)) {
var ibDelete = (ImageButton)e.Item.FindControl("ibDelete");
ibDelete.CommandArgument = e.Item.DataItem.ToString();
}
}
protected void Button_Command(object sender, EventArgs e) {
var btn = (IButtonControl)sender;
switch (btn.CommandName) {
case "Delete":
//delete it
break;
}
}
Try using this code instead:
<asp:Repeater ID="rptExpenses" runat="server">
<ItemTemplate>
<asp:ImageButton ID="ibRemove" ImageUrl="~/Images/delete.png" runat="server"
CommandName="Remove"
CommandArgument='<%# Container.DataItem %>'
OnCommand="ibRemove_Click"/>
</ItemTemplate>
</asp:Repeater>
And this in the code behind:
protected void Page_Load(object sender, EventArgs e) {
if (!IsPostBack) {
rptExpenses.DataSource = ExpenseIds;
rptExpenses.DataBind();
}
}
protected void ibRemove_Click(object sender, CommandEventArgs e)
{
var btn = (IButtonControl)sender;
switch (btn.CommandName)
{
case "Remove":
//delete it, use btn.CommandArgument to find id to remove
break;
}
}
If you still receive the ... Invalid postback or callback argument. Event validation is enabled using ... error, it most likely means that you are somewhere re-binding the repeater before the ibRemove_Click(...) event is raised.
I found the reason why this was happening in the answer to this question: Why ItemCommand doesn't fired on My Repeater
Turns out that for some reason the Page's DataBind function was invalidating the repeater's controls without passing through the repeater's OnItemDataBound function a second time.
I have the following code in my aspx page:
<asp:Literal ID="ltPost" runat="server"></asp:Literal>
and this in my code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack) {
BindData();
}
}
protected void BindData() {
str.Append(#"<asp:Button ID=*btnEditReply* runat=*server* CssClass=*button-action m-r-5* Text=*Sửa phản hồi* ValidationGroup=*AddSave*/>");
ltPost.Text = str.ToString().TrimEnd(',').Replace('*', '"');
}
I don't understand this; Why won't the button btnEditReply display?
To add a server control, you have to use Controls.Add(). Also, you can't add a button to a literal, so it's better to use a Placeholder.
C#:
Button editButton = new Button();
editButton.ID = "btnEditReply";
editbutton.Text = "Sửa phản hồi";
// .. etc
placeHolder.Controls.Add(editButton);
HTML:
<asp:Placeholder id="placeHolder" runat="server" />
Reference: http://msdn.microsoft.com/en-us/library/kyt0fzt1(v=vs.100).aspx
I have a textbox and submit button created using the design mode.
When the submit button is pressed, it will retrieve the user input from the textbox and then make a query to my database.
It will then display a list of dynamic buttons according to the information retrieved from my database.
However, the event handler for the buttons does not fire when clicked. I guess my problem is the postback but I cannot create those buttons in page_load etc. because I need to get the user input (from the textbox when submit button is pressed) before i can load the buttons.
How can i solve this problem?
Thank you.
Edit (codes):
protected void subBtn_Click(object sender, EventArgs e)
{
//database setup codes
.......
while (reader.Read())
{
Button detailsBtn = new Button();
detailsBtn.Text = reader["fName"].ToString();
//doesn't fire
detailsBtn.Click += new EventHandler(detailsBtn_Click);
memPanel.Controls.Add(detailsBtn);
}
}
Main problem is Postback regenerate dynamic controls on each postback if those controls does not exists.
For quick demo see this code
ASPX CODE
<form id="form1" runat="server">
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" />
<asp:Panel ID="pnl" runat="server"></asp:Panel>
</form>
ASPX.CS CODE
protected void Page_Load(object sender, EventArgs e)
{
if(IsPostBack)
{
generate();
}
}
public void generate()
{
if (!pnl.HasControls())
{
for (int i = 0; i < 4; i++)
{
Button detailsBtn = new Button();
detailsBtn.Text = "fName" + i.ToString();
detailsBtn.ID = i.ToString();
detailsBtn.Click += new EventHandler(detailsBtn_Click);
pnl.Controls.Add(detailsBtn);
}
}
}
protected void Button1_Click(object sender, EventArgs e)
{
generate();
}
protected void detailsBtn_Click(object sender, EventArgs e)
{
}
Sound to me like you could easily refactor your page to use a simple <asp:Repeater runat="server" ..></asp:Repeater> instead of dynamically adding controls to a Panel.
Here is a very simple complete sample:
RepeaterTest.aspx
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent" runat="Server">
<asp:TextBox ID="theTextBox" runat="server"></asp:TextBox>
<asp:Button ID="theButton" runat="server" OnClick="theButton_Click" Text="Click me" />
<asp:Repeater ID="test" runat="server">
<ItemTemplate>
<asp:Button ID="theRepeaterButton" runat="server" Text='<%# Eval("fName") %>' OnClick="theRepeaterButton_Click" />
</ItemTemplate>
</asp:Repeater>
</asp:Content>
RepeaterTest.aspx.cs
public partial class RepeaterTest : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void theButton_Click(object sender, EventArgs e)
{
string filter = theTextBox.Text;
// below row simulates fetching data using the filter text in the text box
var data = Enumerable.Range(0, 20).Select(i => new { fName = filter + " " + i });
test.DataSource = data;
test.DataBind();
}
protected void theRepeaterButton_Click(object sender, EventArgs e)
{
var button = (Button)sender;
// do something here based on text/commandname/commandargument etc of the button
}
}
I have a ListView that has a FileUpload control and a button in each ListViewItem.
I have an OnClick event on my button where i try and pull information from the FileUpload control, but when I try to access the control all of the values that were set are gone (FileName etc).
What do I need to do differently here to access the information I just entered?
<asp:ListView ID="lv_Uploads" runat="server" OnItemDataBound="GetThumbs" EnableViewState="true" >
<LayoutTemplate>
<div id="itemPlaceholder" runat="server" />
</LayoutTemplate>
<ItemTemplate>
<div style="width:500px;>
<asp:FileUpload runat="server" ID="fu_Upload" />
<asp:Button ID="btn_Save" runat="server" Text="Save File" OnClick="SaveFile" />
<br />
</div>
</ItemTemplate>
</asp:ListView>
Code behind:
protected void SaveFile(object sender, EventArgs e)
{
//This always evaluates to an empty string...
string myFile = ((FileUpload)((Button)sender).Parent.FindControl("fu_Upload")).FileName;
}
I tested the code you provided for the aspx and the following as the code behind:
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
lv_Uploads.DataSource = data;
lv_Uploads.DataBind();
}
}
protected void SaveFile(object sender, EventArgs e)
{
//This always evaluates to an empty string...
string myFile = ((FileUpload)((Button)sender).Parent.FindControl("fu_Upload")).FileName;
}
protected void GetThumbs(object sender, ListViewItemEventArgs e)
{
}
protected IEnumerable<string> data = new string[] { "test1", "test2", "test3" };
The FileUpload control had data for me on PostBack.
Are you using an UpdatePanel around the ListView? FileUpload controls are not compatible with UpdatePanels.
See:
FileUpload control inside an UpdatePanel without refreshing the whole page?
and
http://msdn.microsoft.com/en-us/library/bb386454.aspx#UpdatePanelCompatibleControls
Is the ListView control being rebound before SaveFile is fired on PostBack? If so, it would wipe out any values the user entered.
I am trying to set a ViewState-variable when a button is pressed, but it only works the second time I click the button. Here is the code-behind:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
lblInfo.InnerText = String.Format("Hello {0} at {1}!", YourName, DateTime.Now.ToLongTimeString());
}
}
private string YourName
{
get { return (string)ViewState["YourName"]; }
set { ViewState["YourName"] = value; }
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
YourName = txtName.Text;
}
Is there something I am missing? Here is the form-part of the design-file, very basic just as a POC:
<form id="form1" runat="server">
<div>
Enter your name: <asp:TextBox runat="server" ID="txtName"></asp:TextBox>
<asp:Button runat="server" ID="btnSubmit" Text="OK" onclick="btnSubmit_Click" />
<hr />
<label id="lblInfo" runat="server"></label>
</div>
</form>
PS: The sample is very simplified, "use txtName.Text instead of ViewState" is not the correct answer, I need the info to be in ViewState.
Page_Load fires before btnSubmit_Click.
If you want to do something after your postback events have fired use Page_PreRender.
//this will work because YourName has now been set by the click event
protected void Page_PreRender(object sender, EventArgs e)
{
if (Page.IsPostBack)
lblInfo.InnerText = String.Format("Hello {0} at {1}!", YourName, DateTime.Now.ToLongTimeString());
}
The basic order goes:
Page init fires (init cannot access ViewState)
ViewState is read
Page load fires
Any events fire
PreRender fires
Page renders