Develop Reference

Button created from code behind disappeared after click [duplicate]

Actually, I am Creating 1 TextBox on Pageload and adding that TextBox to Panel.
Now, I have a LinkButton like Add Another.
I am entering Text in that TextBox and if needed I need to Create New TextBox,by clicking Add Another LinkButton.
Actually, I am able to get the count and recreate the TextBoxes.
But,the Problem is that, My Entered text in the Previously Generated Textboxes is Missing.
Can Anyone,Suggest me a solution for this?
protected void Page_Load(object sender, EventArgs e)
{
try
{
if (!IsPostBack)
{
for (int i = 0; i < 5; i++)
{
TableRow row = new TableRow();
for (int j = 0; j < 5; j++)
{
TableCell cell = new TableCell();
TextBox tb = new TextBox();
tb.ID = "TextBoxRow_" + i + "Col_" + j;
cell.Controls.Add(tb);
row.Cells.Add(cell);
}
Table1.Rows.Add(row);
}
}
}
catch (Exception ex)
{
throw;
}
}
This is a Sample Code, the same code is written in Button_Click Also
protected void ASPxButton1_Click(object sender, EventArgs e)
{
int k = Table1.Controls.Count;
}
I am getting a Count=0 on Button_Click.

All you need to do is to re-instantiate / reinitialize dynamic controls before or within page load event each and every time during postback and add this control to page / forms / placeholders. Then, the posted data will automatically be assigned to the control by calling the LoadPostData method by the parent control.
check the article and how to write code for dynamic control -
How to maintain dynamic control events, data during postback in asp.net

When using dynamic controls, you must remember that they will exist only until the next postback.ASP.NET will not re-create a dynamically added control. If you need to re-create a control multiple times, you should perform the control creation in the PageLoad event handler ( As currently you are just creating only for first time the TextBox using Condition: !IsPostabck ). This has the additional benefit of allowing you to use view state with your dynamic control. Even though view state is normally restored before the Page.Load event, if you create a control in the handler for the PageLoad event, ASP.NET will apply any view state information that it has after the PageLoad event handler ends.
So, Remove the Condition: !IsPostback, So that each time the page Loads, The TextBox control is also created. You will also see the State of Text box saved after PageLoad handler completes. [ Obviously you have not disabled ViewState!!! ]
Example:
protected void Page_Load(object sender, EventArgs e)
{
TextBox txtBox = new TextBox();
// Assign some text and an ID so you can retrieve it later.
txtBox.ID = "newButton";
PlaceHolder1.Controls.Add(txtBox);
}
Now after running it, type anything in text box and see what happens when you click any button that causes postback. The Text Box still has maintained its State!!!

The dynamically generated control do not maintain state. You have to maintain it at your own. You can use some hidden field to keep the state of controls, which will be used on server side to extract the state. Asp.net uses hidden field to maintain the state between requests, you can see __VIEWSTATE in the source.
In ASP.NET pages, the view state represents the state of the page when
it was last processed on the server. It's used to build a call context
and retain values across two successive requests for the same page. By
default, the state is persisted on the client using a hidden field
added to the page and is restored on the server before the page
request is processed. The view state travels back and forth with the
page itself, but does not represent or contain any information that's
relevant to client-side page display, Reference.

Just remove this line
if (!IsPostBack)

This is My final answer after working a lot with Dynamic Controls
.aspx
<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<div style="text-align: center">
<div style="background-color: Aqua; width: 250px;">
<br />
<asp:UpdatePanel ID="UpdatePanel1" runat="server">
<ContentTemplate>
<asp:PlaceHolder runat="server" ID="myPlaceHolder"></asp:PlaceHolder>
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="btnAddTextBox" EventName="Click" />
</Triggers>
</asp:UpdatePanel>
<br />
</div>
<br />
<asp:Button ID="btnAddTextBox" runat="server" Text="Add TextBox" OnClick="btnAddTextBox_Click" />
<br /><br />
<asp:UpdatePanel ID="UpdatePanel2" runat="server">
<ContentTemplate>
<asp:Button runat="server" ID="MyButton" Text="Get Values." OnClick="MyButton_Click" />
<br /><br />
<asp:Label runat="server" ID="MyLabel"></asp:Label>
</ContentTemplate>
</asp:UpdatePanel>
</div>
</form>
.aspx.cs
static int myCount = 0;
private TextBox[] dynamicTextBoxes;
protected void Page_PreInit(object sender, EventArgs e)
{
Control myControl = GetPostBackControl(this.Page);
if ((myControl != null))
{
if ((myControl.ClientID.ToString() == "btnAddTextBox"))
{
myCount = myCount + 1;
}
}
}
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
dynamicTextBoxes = new TextBox[myCount];
int i;
for (i = 0; i < myCount; i += 1)
{
TextBox textBox = new TextBox();
textBox.ID = "myTextBox" + i.ToString();
myPlaceHolder.Controls.Add(textBox);
dynamicTextBoxes[i] = textBox;
LiteralControl literalBreak = new LiteralControl("<br />");
myPlaceHolder.Controls.Add(literalBreak);
}
}
protected void btnAddTextBox_Click(object sender, EventArgs e)
{
// Handled in preInit due to event sequencing.
}
protected void MyButton_Click(object sender, EventArgs e)
{
MyLabel.Text = "";
foreach (TextBox tb in dynamicTextBoxes)
{
MyLabel.Text += tb.Text + " :: ";
}
}
public static Control GetPostBackControl(Page thePage)
{
Control myControl = null;
string ctrlName = thePage.Request.Params.Get("__EVENTTARGET");
if (((ctrlName != null) & (ctrlName != string.Empty)))
{
myControl = thePage.FindControl(ctrlName);
}
else
{
foreach (string Item in thePage.Request.Form)
{
Control c = thePage.FindControl(Item);
if (((c) is System.Web.UI.WebControls.Button))
{
myControl = c;
}
}
}
return myControl;
}

When you are working with dynamic controls they will not able to maintain its state during postback and their data lost Cause they dont have any viewstate to maintain their data.
You only need to maintain the created controls data into ViewState
dynamically and loads the data into page at the time of postback and you
done.
public Dictionary<Guid, string> UcList
{
get { return ViewState["MyUcIds"] != null ? (Dictionary<Guid, string>)ViewState["MyUcIds"] : new Dictionary<Guid, string>(); }
set { ViewState["MyUcIds"] = value; }
}
public void InitializeUC()
{
int index = 1;
foreach (var item in UcList)
{
var myUc = (UserControls_uc_MyUserControl)LoadControl("~/UserControls/uc_MyUserControl.ascx");
myUc.ID = item.Value;
pnlMyUC.Controls.AddAt(index, myUc);
index++;
}
}
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
LoadControl();
else
InitializeUC();
}

Actually, I have used Javascript for accomplishing my task.
and it goes like this :
<form id="form1" runat="server" enctype="multipart/form-data" method="post">
<span style="font-family: Arial">Click to add files</span>
<input id="Button1" type="button" value="add" onclick="AddFileUpload()" />
<br />
<br />
<div id="FileUploadContainer">
<!--FileUpload Controls will be added here -->
</div>
<asp:HiddenField ID="HdFirst1" runat="server" Value="" />
<br />
<asp:Button ID="btnUpload" runat="server" Text="Upload" OnClick="btnUpload_Click" />
</form>
Script :
<script type="text/javascript">
var counter = 0;
function AddFileUpload() {
var div = document.createElement('DIV');
div.innerHTML = '<input id="file' + counter + '"name = "file' + counter + '"type="text"/><input id="file' + counter + '" name = "file' + counter + '" type="file" /><input id="Button' + counter + '" type="button" value="Remove" onclick = "RemoveFileUpload(this)" />';
document.getElementById("FileUploadContainer").appendChild(div);
counter++;
}
function RemoveFileUpload(div) {
document.getElementById("FileUploadContainer").removeChild(div.parentNode);
}
function mydetails(div) {
var info;
for (var i = 0; i < counter; i++) {
var dd = document.getElementById('file' + i).value;
info = info + "~" + dd;
}
document.getElementById('<%= HdFirst1.ClientID %>').value = info;
}
</script>
and In the Upload_Click Button :
for (int i = 0; i < Request.Files.Count; i++)
{
string strname = HdFirst1.Value;
string[] txtval = strname.Split('~');
HttpPostedFile PostedFile = Request.Files[i];
if (PostedFile.ContentLength > 0)
{
string FileName = System.IO.Path.GetFileName(PostedFile.FileName);
// string textname=
//PostedFile.SaveAs(Server.MapPath("Files\\") + FileName);
}
}

Dynamic Div creation asp.net

I am trying to create Div dynamically on the press of button click.
For that i refered this link>> http://forums.asp.net/t/1349244.aspx
and made code on server side(.cs page) as follows>>
public static int i = 0;
protected void Button1_Click(object sender, EventArgs e)
{
i++;
HtmlGenericControl newControl = new HtmlGenericControl("div");
newControl.ID = "NEWControl"+i;
newControl.InnerHtml = "This is a dynamically created HTML server control.";
PlaceHolder1.Controls.Add(newControl);
}
This code was giving me just one div each time when i press the button., I wanted to have addition of divs.
On client side using javascript also i tried>>
<body>
<form id="form1" runat="server">
<div>
<asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" OnClientClick="addDiv();" />
</div>
<asp:PlaceHolder ID="PlaceHolder1" runat="server"></asp:PlaceHolder>
</form>
</body>
</html>
<script type="text/javascript">
function addDiv() {
alert("Control comming in function");
var r = document.createElement('Div');
r.style.height = "20px";
r.style.width = "25px";
r.appendChild("div");
alert("Control going out of function");
}
</script>
Both of these didnt work.
What mistake am i making?
Is there any thing wrong?

Use this
public int Index
{
get
{
if(ViewState["Index"]==null)
{
ViewState["Index"]=0;
}
else
{
ViewState["Index"]=int.Parse(ViewState["Index"].ToString())+1;
}
return int.Parse(ViewState["Index"].ToString());
}
}
protected void Button1_Click(object sender, EventArgs e)
{
HtmlGenericControl newControl = new HtmlGenericControl("div");
newControl.ID = "NEWControl"+Index;
newControl.InnerHtml = "This is a dynamically created HTML server control.";
PlaceHolder1.Controls.Add(newControl);
}

It is giving you one div, cause you are adding one div.
Remember that asp.net needs you to create all dynamically added controls on very PostBack after that.
If you want two controls you have to add two to the PlaceHolder.

Just use one parent div with some ID(predefined lets say id="dvDynamic") and runat="server"
and then use it the dvDynamic.innerHTML = "<div> /* dynamic div contents */ </div>"
Its the simplest way, as if you are using html element in ASP.net use dom controls for better generation. Dynamic creation of control will require handled, interface and many things to co-ordinate with that control. As its not predefined by system. you have to create it.
SO choose the DOM element option. that is faster and better :)
I hope this will help :)

show list selected no of list box on each checked

I have a asp:CheckBoxList which load items from database.
I want to write a script which shows no. of checked checkbox on each check.
My aspx page is as following :
<div id="rfd-demo-zone2" class="placeholderContent accordionEmpGroup-child-subGroup-container">
<asp:CheckBoxList ID="ckbList2DesignationUc" runat="Server" RepeatLayout="Flow" RepeatDirection="Horizontal" Width="100%" ></asp:CheckBoxList>
</div>
script :
<script type="text/javascript">
$('#ckbList2DesignationUc input:checked').each(function () {
alert('hi');
});
</script>
In the above script I am trying to get an alert, but it is not showing

Put script in document.ready to ensure the availability of html elements to script and use attribute contains selector to find the checkboxes of the checkboxlist.
<script type="text/javascript">
$(document).ready(function(){
$('[id*=ckbList2DesignationUc]:checked').each(function () {
alert('hi');
});
});
</script>
To fire event on change of checkbox
<script type="text/javascript">
$(document).ready(function(){
$('[id*=ckbList2DesignationUc]').change(function () {
alert(this.id);
});
});
</script>

Client side:
$('.CheckBoxList').each(function () {
var items = new Array();
$(this).find("input:checkbox").each(function () {
if ($(this).attr("checked") == true) {
items[items.length] = $(this).next().html();
}
});
$(this).parent().find('.txtList').val(items.toString());
});
Html MarkUp:
<asp:TextBox runat="server" ID="txtabc" CssClass="txtList txtformatcss" Width="160px" ViewStateMode="Disabled"></asp:TextBox>
<asp:CheckBoxList ID="chkabc" runat="server"
RepeatLayout="Flow" CssClass="CheckBoxList">
</asp:CheckBoxList>
Here CheckBoxList is class name which have given in checkboxlist control

Possible solution:
<div id="rfd-demo-zone2" class="placeholderContent accordionEmpGroup-child-subGroup-container">
<asp:CheckBoxList ID="ckbList2DesignationUc" runat="Server" RepeatLayout="Flow" RepeatDirection="Horizontal" Width="100%" >
</asp:CheckBoxList>
</div>
and access it:
$("#<%=ckbList2DesignationUc.ClientID %> input[type=checkbox]:checked").each(function() {
alert('checked');
});

Try below code :
Solution-1
Whenever you will check checkbox an alert will show you the values of checked items in checkboxes.
Javascript code :
< script type="text/javascript">
function itemClick(radioButton) {
var Control;
var selectedItems;
selectedItems = '';
Control = document.getElementById("<%=ckbList2DesignationUc.ClientID %>").getElementsByTagName("input");
for (var i = 0; i < Control.length; i++) {
if (Control[i].checked == true)
selectedItems += i.toString()+',';
}
alert(selectedItems);
}
</script>
ASPX Code :
protected void Page_Load(object sender, EventArgs e)
{
for (int index = 0; index < 10; index++)
{
ckbList2DesignationUc.Items.Add(new ListItem("Item" + index, index.ToString()));
}
foreach (ListItem Li in ckbList2DesignationUc.Items)
{
Li.Attributes.Add("onclick", "return itemClick()");
}
}
Required solution by using Jquery :
Solution -2
< script type="text/javascript">
$(document).ready(function () {
var selectedCheckBoxes = '';
$('#ckbList2DesignationUc').each(function () {
var items = new Array();
$(this).find("input:checkbox").each(function () {
$(this).click(function () {
selectedCheckBoxes += $(this).val() + ",";
alert(selectedCheckBoxes);
});
});
});
});
< /script>
< asp:CheckBoxList ID="ckbList2DesignationUc" runat="Server" RepeatLayout="Flow" RepeatDirection="Horizontal" Width="100%">
< /asp:CheckBoxList>

This may help you: you can use it in code behind file as well as inside the script tag enable AutoPostBack property of checkboxlist to true
protected void CheckBoxList1_SelectedIndexChanged(object sender, EventArgs e)
{
int i=0;
foreach (ListItem li in CheckBoxList1.Items)
{
if (li.Selected)
i++;
}
Response.Write(i);
}

Yet another viewstate dropdownlist issue

I have the following code in the Page_Load method of a web form:
protected void Page_Load(object sender, EventArgs e)
{
CountrySelectButton.Click += new EventHandler(CountrySelectButton_Click);
if (HomePage.EnableCountrySelector) //always true in in this case
{
if(!IsPostBack)
BindCountrySelectorList();
}
}
The BindCountrySelectorList method looks like this:
private void BindCountrySelectorList()
{
NameValueCollection nvc = HttpUtility.ParseQueryString(HomePage.CountryList);
var ds = nvc.AllKeys.Select(k => new { Text = k, Value = nvc[k] });
CountrySelector.DataSource = ds;
CountrySelector.DataTextField = "Text";
CountrySelector.DataValueField = "Value";
CountrySelector.DataBind();
}
And I have a LinkButton click event handler which gets the SelectedValue from the SelectList as so:
void CountrySelectButton_Click(object sender, EventArgs e)
{
//get selected
string selectedMarket = CountrySelector.SelectedValue; //this is always the first item...
//set cookie
if (RememberSelection.Checked)
Response.Cookies.Add(new HttpCookie("blah_cookie", selectedMarket) { Expires = DateTime.MaxValue });
//redirect
Response.Redirect(selectedMarket, false);
}
EDIT:
This is the DDL and LinkButton definition:
<asp:DropDownList runat="server" ID="CountrySelector" />
<asp:LinkButton runat="server" ID="CountrySelectButton" Text="Go" />
Resulting markup:
<select name="CountrySelector" id="CountrySelector">
<option value="http://google.com">UK</option>
<option value="http://microsoft.com">US</option>
<option value="http://apple.com">FR</option>
</select>
<a id="CountrySelectButton" href="javascript:__doPostBack('CountrySelectButton','')">Go</a>
END EDIT
ViewState is enabled but the SelectedValue property only ever returns the first item in the list regardless of which item is actually selected. I'm certain I'm missing something obvious but I can't find the problem; any help is much appreciated.
Thanks in advance.
Dave

You are correct that your issue stems from the jquery ui dialog... you can get around this by using a hidden field to record the value of the dropdownlist. Then in your code, reference the hidden field.
Front end could look like:
<div id="myModal" style="display: none;">
<asp:DropDownList runat="server" ID="SelectList" />
<asp:LinkButton runat="server" ID="MyButton" Text="Go" />
</div>
<input type="hidden" id="countryVal" runat="server" />
<a id="choose" href="#">Choose</a>
<script type="text/javascript">
$(document).ready(function () {
$('#choose').click(function () {
$('#myModal').dialog({
});
return false;
});
$('#<%= SelectList.ClientID %>').change(function () {
var country = $(this).val();
$('#<%= countryVal.ClientID %>').val(country);
});
});
</script>
Then your code behind:
var selected = countryVal.Value;

Wrap the MyButton.Click+=... statement inside (!IsPostBack) like
if(!IsPostBack)
{
MyButton.Click += new EventHandler(MyButton_Click);
BindSelectList();
}

How to open Telerik Rad Pop Up window Asynchronously?

I am opening a Telerik RadWindowManager Pop up.
There is a long Database operation to be performed.
During loading i.e. approximately for 35-40 seconds, for the moment, I keep on waiting until the process will come to an end.
Is there any way to load the design first and show a Loader / progress bar to inform the user to wait...Actually the problem gets worse when the Internet speed is slow...
Any suggestion....

Here I have a good example. See here for demo.
aspx file:
<telerik:RadScriptManager id="ScriptManager1" runat="server" />
<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server" OnAjaxRequest="RadAjaxManager1_AjaxRequest"/>
<p>
Press the submit button in order to start monitoring custom progress
</p>
<asp:button ID="buttonSubmit" runat="server" Text="Submit" OnClick="buttonSubmit_Click" CssClass="RadUploadButton" />
<telerik:RadProgressManager id="Radprogressmanager1" runat="server" />
<telerik:RadProgressArea id="RadProgressArea1" runat="server" />
aspx.cs file:
protected void Page_Load(object sender, System.EventArgs e)
{
if (!IsPostBack)
{
//Do not display SelectedFilesCount progress indicator.
RadProgressArea1.ProgressIndicators &= ~ProgressIndicators.SelectedFilesCount;
}
RadProgressArea1.Localization.Uploaded = "Total Progress";
RadProgressArea1.Localization.UploadedFiles = "Progress";
RadProgressArea1.Localization.CurrentFileName = "Custom progress in action: ";
}
protected void buttonSubmit_Click(object sender, System.EventArgs e)
{
UpdateProgressContext();
}
private void UpdateProgressContext()
{
const int total = 100;
RadProgressContext progress = RadProgressContext.Current;
progress.Speed = "N/A";
for (int i = 0; i < total; i++)
{
progress.PrimaryTotal = 1;
progress.PrimaryValue = 1;
progress.PrimaryPercent = 100;
progress.SecondaryTotal = total;
progress.SecondaryValue = i;
progress.SecondaryPercent = i;
progress.CurrentOperationText = "Step " + i.ToString();
if (!Response.IsClientConnected)
{
//Cancel button was clicked or the browser was closed, so stop processing
break;
}
progress.TimeEstimated = (total - i) * 100;
//Stall the current thread for 0.1 seconds
System.Threading.Thread.Sleep(100);
}
}
Now it should be easier to integrate your code.
EDIT: To trigger your Database operation after setting up your RadProgressArea in the PageLoad, you'll need some ajax call to be made after first page load (So I just added the RadAjaxManager to the ascx file upper). Use this code to trigger your DataBase call:
javascript:
function pageLoad(sender, eventArgs) {
if (!eventArgs.get_isPartialLoad()) {
$find("<%= RadAjaxManager1.ClientID %>").ajaxRequest("StartDBOperation");
}
}
ascx.cs file:
protected void RadAjaxManager1_AjaxRequest(object sender, Telerik.Web.UI.AjaxRequestEventArgs e)
{
if (e.Argument == "StartDBOperation")
{
// Start DB operation here..
}
}

Still an Alternative below... But not a solution
I can show a loading panel as follows while the content loads
Mark Up
<div id="loading" style=" width: 100px; height: 50px; display: none;
text-align: center; margin: auto;">
loading...
</div>
<asp:Button ID="RadButton1" runat="server"
Text="RadButton1" OnClientClick="openRadWnd(); return false;" />
<telerik:RadWindowManager ID="RadWindowManager1" runat="server">
<Windows>
<telerik:RadWindow ID="RadWindow1" runat="server"
NavigateUrl="url" ShowContentDuringLoad="false"
OnClientShow="OnClientShow" OnClientPageLoad="OnClientPageLoad">
</telerik:RadWindow>
</Windows>
</telerik:RadWindowManager>
JavaScript
<script type="text/javascript">
var loadingSign = null;
var contentCell = null;
function openRadWnd() {
$find("<%=RadWindow1.ClientID %>").show();
}
function OnClientShow(sender, args) {
loadingSign = $get("loading");
contentCell = sender._contentCell;
if (contentCell && loadingSign) {
contentCell.appendChild(loadingSign);
contentCell.style.verticalAlign = "middle";
loadingSign.style.display = "";
}
}
function OnClientPageLoad(sender, args) {
if (contentCell && loadingSign) {
contentCell.removeChild(loadingSign);
contentCell.style.verticalAlign = "";
loadingSign.style.display = "none";
}
}
</script>

Open the RadWindow with JavaScript on the client, set the desired URL through JavaScript. Performa partial postbacks that do not dispose the RadWindow. If you obtain the URL on the server only - use the same logic, but show the loading sign initially, when the response is done call a script to change the URL of the RadWIndow again.
http://www.telerik.com/help/aspnet-ajax/window-programming-opening.html
http://www.telerik.com/help/aspnet-ajax/window-troubleshooting-javascript-from-server-side.html
http://www.telerik.com/help/aspnet-ajax/window-programming-radwindow-methods.html