Asp .net Linkbutton child controls dissapears on postback - c#

I have an asp .net hyperlink control declared like this:
<li runat="server" id="liveChatCtrl" Visible="false"><asp:LinkButton runat="server" ID="hlnkLiveChat" CausesValidation="false" OnClick="hlnkLiveChat_Click">Live Chat Support <i class="icon icon_next_03 fr"></i><i runat="server" id="iconChat" class="icon_chat_online"></i></asp:LinkButton></li>
My problem is that the contents of the linkbutton disappears on postback. Any ideas why this is happening?
On load I execute the following code on the linkbutton or it's children:
string absoluteURL = UtilManager.Settings.Item(Utils.BrandID, "URL:absoluteURL");
string chatLink = "StartChat.aspx";
if (HttpContext.Current.User.Identity.IsAuthenticated)
chatLink = "LiveChat.aspx";//~/
//else
// chatLink = "SalesChat.aspx";
string link = absoluteURL + chatLink;
hlnkLiveChat.Attributes["onclick"] = string.Format("javascript:window.open( '{0}', 'chat', 'status=no,toolbar=no,menubar=no,location=no,scrollbars=yes,resizable=yes,height=505,width=420,left=30,top=30');", link);//"openPopup('" + link + "','chat'); return false;";
liveChatCtrl.Visible = true;

A guess...
I believe you may have the code in your Page_Load (or Init) inside an if(!IsPostBack)
If this is the case, move it outside of this if statement as you need it to run as your default visible for your liveChatCtrl is false
Either that or re-code a little so that your default visible is true and you run a check on postback to hide it if needed.

Related

Asp.net: Response.Write OnServerClick codebehind function not working

I'm trying to make it so if your Session["LoggedIn"] is true, the wuc (Web User Control, which is the Navbar and is connected to the MasterPage which is connected to the page) prints a logout button.
so I have it like this:
Response.Write("<a runat='server' ID='lblLogout' class='nav-link' CausesValidation='False' OnServerClick='lblLogout_Click'>Logout</a>");
the CodeBehind function looks like this:
protected void lblLogout_Click(object sender, EventArgs e)
{
Session.RemoveAll();
Session["LoggedIn"] = false;
Session["IsAdmin"] = false;
Session["Username"] = "";
}
now, I've tried everything, if I use response.write like that, I can't click it, it just doesn't fire or do anything, if I don't use it inside Response.Write, it does work..
I even tried prinitng an asp:LinkButton instead to see if that works, but it doesn't print out anything when I use it like:
Response.Write("<asp:LinkButton class='nav-link' runat='server' ID='lblLogout' Text='Logout' CausesValidation='False' OnClick='lblLogout_Click' />");
Now the solution that I found was putting another page for logout and placing the function on PageLoad, which works, but I'm wondering if I can make it work so I can use the function from CodeBehind, instead of having to go to another page.
my working solution:
if ((bool)Session["LoggedIn"] == true)
{
Response.Write("<li class='nav-item'> <a runat='server' ID='lblLogout' class='nav-link' CausesValidation='False' href='../PagesForVisitor/wfLogout.aspx'>Logout</a></li><li><a class='navbar-brand' href='#'><img src='" + GetSource() + "' width = '30' height = '30' alt = ''/ ></a></li>");
}
(this one prints out a profile pic as well)
p.s using Bootstrap for styling, not sure if that matters, thanks a bunch..
You should use
<asp:Button id='' runat='server'>
tag
or use css to custom the button look depending on the style.
You can make it a hyperlink in the properties.

ASP.Net WebForms LinkButton click, open new tab, passing id through hidden html input variable

I have an aspx webforms page with a repeater built through a user control. Each repeater item has a link button. What I want to happen is that when the LinkButton (in the repeater on page A's user control) is clicked, the url is opened in a new tab, and a hidden id next to that LinkButton is passed (according web development best practices for security if possible) to the aspx page (page B) in the new tab. Both pages A and page B are in the same application.The intent of what I described above is so that the user can easily return to their search results after returning from the URL opened by clicking on the LinkButton.I am open to ideas on how to do this that are closer to standard best-practice methods.
So far, I have tried:
1) cross-page posting – this worked for passing the id, but not for opening in a new tab.
2) Setting the PostBackUrl to page B's url, setting the Page.Form.Target="_blank" with OnClientClick calling javascript to set the hidden id from the user control to the value of an html hidden input on page B and also.
3) I also tried using window.open("page B url", "_newtab") in OnClientClick.
a) So far, the only method that worked correctly was the 2nd one from the 3 different methods above. However, after page B is loaded in the new tab, I don't know how to reset page A's Page.Form.Target back to what it was previously before setting it to "_blank"
b) The methods that I have tried, to no avail, to reset the Page.Form.Target have been:
1) Resetting the target in page A's Page_Load where IsPostBack == true --> that caused Page B to load with the same content as Page A.
2) Resetting the target in page A's user control's Page_Load --> same result as method 1
3) Resetting the target in page A’s user control’s LinkButton’s OnUnLoad in page A's user control --> same result as method 1
4) Resetting the target in javascript through the LinkButton’s OnClientClick --> didn’t work
5) Resetting the target in page B's Page_Load using a public variable from page A containing a reference to page A's form (similar to what can be done through cross-page posting) --> didn’t work.
What I am thinking about trying next is:
1) Wrapping another user control on page A to display page B's content, in an asp Panel (Panel B)
2) Put page B’s content into the new user control page
3) Wrapping the search results content on page A in an asp Panel (Panel A).
4) When the LinkButton in the repeater on the new user control is clicked, the search results content in Panel A will be hidden, and Panel B will be shown.
5) When the user wants to return to the search results, they will click on a ‘Return to Search’ LinkButton in Panel B’s content, and then Panel B will be hidden, then content of Panel B will be cleared, and Panel A will be shown again.
I'm not yet sure if that will work though. It doesn't seem like this should be that difficult. It is a straight-forward concept, and I would think is a fairly common situation in web development.
I feel like Wiley Coyote trying to catch the Road Runner because I come up with elaborate intelligent, thought-out plans that all completely fail. I am now holding up a little sign that says, "Help!
I had the same issue resolve by the following code you just try this in ur HTML page for a button in GRIDVIEW:
<asp:LinkButton ID="LinkButton1" runat="server" Text="View" CommandArgument='<%# Bind("ref") %>'
OnClick="LinkButton1_Click" OnClientClick="document.forms[0].target ='_blank';">View</asp:LinkButton>***
I actually got this figured out.
I figured it out through a combination of the marked-answer on this post, How to Open new tab when we click on LinkButton, and the marked-answer on this post, Is it possible add click event to hyperlink?.
My Repeater ItemTemplate in the user control's repeater looks similar to this:
<asp:HiddenField ID="hfId" runat="server"
Value='<%# Eval("Id") %>'/>
<asp:HyperLink ID="myLink" runat="server"
Text='<%# Eval("Name") %>'
NavigateUrl="/myUrl.aspx"
Target="_blank" />
<asp:Button ID="btnSubmit" runat="server"
Text="Submit"
OnClick="BtnClick"
Style="display: none;" />
This is my code in the ItemDataBound of the repeater:
protected void RptrItemDataBound(object sender, RepeaterItemEventArgs e)
{
if (e.Item.ItemType == ListItemType.Item || e.Item.ItemType == ListItemType.AlternatingItem)
{
var myId = "";
var myNameLink = e.Item.FindControl("myLink") as HyperLink;
if (myNameLink != null)
{
var submitButton = e.Item.FindControl("btnSubmit") as Button;
if (submitButton != null)
{
var submitButtonClientId = submitButton.ClientID;
myNameLink.Attributes.Add("onclick", "onNameClick('" + submitButtonClientId + "')");
}
}
}
}//end RptrItemDataBound
The javascript code:
<script type="text/javascript">
function nameClick(buttonId)
{
document.getElementById(buttonId).click();
}
</script>
And here is the BtnClick C# code:
protected void BtnClick(object sender, EventArgs e)
{
var btnSelect = sender as Button;
if (btnSelect == null)
{
return;
}
var myListItem = (RepeaterItem)btnSelect.DataItemContainer;
if (myListItem != null)
{
var hfId = myListItem.FindControl("hfId") as HiddenField;
if (hfId != null)
{
var intId = int.Parse(hfId.Value);
Session["selectedId"] = intId;
}//end if (hfId != null)
}//end if (myListItem != null)
}//end btnClick

ASP.NET OnClick not firing in Repeater.ItemTemplate that has a custom control

Title is a bit of a mouthful, but I'm a bit stuck on this issue.
I have a search result page with has a custom control that has a Repeater. The ItemTemplate in the repeater is a PlaceHolder so I can construct the Item in a particular format; more specifically, I have a string of 'diseases' that come in the form of Disease1|disease2|disease3 and need to be given links for each disease.
Now for some code:
The following is the SearchResultControl.ascx
<asp:Panel ID="SearchResultPanel" runat="server" ScrollBars="Auto">
<asp:Repeater ID="Repeater1" runat="server"
onitemcreated="Repeater1_ItemCreated"
onitemcommand="Repeater1_ItemCommand">
<ItemTemplate>
<asp:PlaceHolder ID="ItemTemplatePlaceHolder" runat="server">
</asp:PlaceHolder>
</ItemTemplate>
<SeparatorTemplate>
<tr>
<td colspan="6"><hr /></td>
</tr>
</SeparatorTemplate>
</asp:Repeater>
</asp:Panel>
The code behind: SearchResultControl.ascx.cs
protected void Repeater1_ItemCreated(object sender, RepeaterItemEventArgs e)
{
if (e.Item.DataItem != null)
{
PlaceHolder placeHolder = e.Item.FindControl("ItemTemplatePlaceHolder") as PlaceHolder;
Control searchResultItem = Page.LoadControl("SearchResultItem.ascx");
DataRow row = (e.Item.DataItem as DataRowView).Row;
if (row != null)
{
string diseaseState = row["DiseaseStates"] as string;
searchResultItem.GetType().GetProperty("DiseaseStates").SetValue(searchResultItem, diseaseState, null);
placeHolder.Controls.Add(searchResultItem);
}
}
}
(Full disclosure, I got this idea from this question)
The SetValue calls the DiseaseStates property in SearchResultItem which in turn calls the following method to build the links, set the text, and the events:
private void BuildDiseaseStateLabels(string diseaseStates)
{
PlaceHolder placeHolder = FindControl("DiseaseStatePlaceHolder") as PlaceHolder;
string[] diseaseStateSplit = diseaseStates.Split(new char[] { '|' }, StringSplitOptions.RemoveEmptyEntries);
int count = diseaseStateSplit.Length;
foreach (string diseaseState in diseaseStateSplit)
{
LinkButton diseaseStateLink = new LinkButton();
diseaseStateLink.Text = diseaseState;
//diseaseStateLink.Click += new EventHandler(OnDiseaseStateLinkClick);
diseaseStateLink.CommandArgument = "<%# Eval(\"PatientID\")+ \";\" + Eval(\"PatientStatus\")+ \";\" + Eval(\"Age\")+ \";\" + Eval(\"DiseaseStates\")%>";
diseaseStateLink.CommandName = "OnDiseaseStateLinkClick";
//diseaseStateLink.Command += new CommandEventHandler(OnDiseaseStateLinkClick);
placeHolder.Controls.Add(diseaseStateLink);
if (count != 0)
{
Label splitLabel = new Label();
splitLabel.Text = "|";
placeHolder.Controls.Add(splitLabel);
}
}
}
This is the layout for the SearchResultItem
<div id="SearchResultItemDiv" class="MainSearchResultItem">
<asp:PlaceHolder ID="DiseaseStatePlaceHolder" runat="server">
</asp:PlaceHolder>
</div>
Initially I tried setting the Click event, but that doesn't work at all. I then set the CommandArgument and CommandName but that didn't seem to do the trick. I figured the Command event might need to be set, but again, no luck. I should note that when a link is clicked the Repeater1_ItemCreated in SearchResultControl.ascx.cs is called. But since there is no data in e.Item.DataItem is null and I lose the results.
In one of the questions regarding the same issue, it was suggested that the OnItemCommand be added, but even that doesn't get called.
I also read A Stumper of an ASP.NET Question and A Stumper of an ASP.NET Question: SOLVED!, to no avail.
What could I possibly be doing wrong? All of the correct event hookups seem there, I'm checking for IsPostBack and not doing DataBind() again. blaaargharaggh
Help is always greatly appreciate.
I believe you're running into this issue because the LinkButton controls are recreated too late in the page lifecycle. You have to remember that when the page is posted back, the control technically does not exist anymore, so the event handler cannot be fired.
If you can recreate the LinkButton controls somewhere before the Page_Load event is reached, like OnInit for example, everything should work fine.
For simple pages the above usually works very well, but there are circumstances where recreating controls during OnInit requires a lot of overhead, such as storing counters or arrays in ViewState so you can keep track of the controls that need to be recreated after postback. In these situations I would suggest taking a look at the DynamicControlsPlaceHolder by Denis Bauer. This control is capable of persisting dynamic controls without any addtional code required, which is pretty awesome.
Here's a link to the latest version:
http://www.denisbauer.com/ASPNETControls/DynamicControlsPlaceholder.aspx
The problem might be that you're not doing the DataBind() again.
Because you're building the buttons on the fly, when the page post backs, the buttons haven't been created and are unable to work out which click event it should be firing.
Try getting rid of the IsPostBack check, so each time the page loads, you're re-build the repeater.

Fetch JS return value in server side page_load event in asp.net

I have an aspx master/content page scenario. The parent page has an IFrame which points to a child.aspx. The child.aspx has a checkbox, On page_load of child.aspx, I want to show/hide the checkbox depending on the following logic:
- if the child.aspx is opened directly, then I have to show the checkbox.
- if the child.aspx is opened in the IFrame, then I have to hide the checkbox.
Basically, I want to check in child.aspx, if it contains a parent window then hide the checkbox control otherwise show it.
I will prefer the show/hide code in codebehind in Page_load event as I have to execute some more logic depending on whether the it is opened from parent window or not.
Till now I did the following:
In child.aspx
<asp:Content ID="Content1" ContentPlaceHolderID="Main" Runat="Server">
<script language="javascript" type="text/javascript">
function DoesParentExists()
{
var bool = (parent.location == window.location)? false : true;
var HClientID ='<%=hfDoesParentExist.ClientID%>';
document.getElementById(HClientID).Value = bool;
}
</script>
<div>
<h2>Content - In IFrame</h2>
<asp:HiddenField runat="server" id="hfDoesParentExist" />
<asp:CheckBox ID="chkValid" runat="server" />
<asp:ImageButton ID="ImageButton_FillW8Online" ImageUrl="~/images/expand.gif"
OnClick="btnVerify_Click" runat="server" style="height: 11px" />
</div>
</asp:Content>
in client.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "DoesParentExists", "DoesParentExists()", true);
if (hfDoesParentExist.Value == "true")
{
chkValid.Visible = false;
}
}
Using RegisterClientScriptBlock, I get error in JS. That the object hfDoesParentExist doesn't exist 'coz the control is not yet created. Right? I tried using RegisterStartupScript but in codebehind I always get null in hidden variable. I don't want to use the on button click or something like it. I need it on page_load event only. How to resolve the issue?
This line:
document.getElementById(HClientID).Value = bool;
Should be: (lower case value)
document.getElementById(HClientID).value = bool;
Also you cannot check the value of a hidden field set by javascript register callback, in the current executing context on the server side.
I would move the logic to the client side to hide or show the checkbox. If the field must indeed be removed from the page you can do that as well with javascript.
function DoesParentExists()
{
var bool = (parent.location == window.location)? false : true;
var cehckboxId ='<%=chkValid.ClientID%>';
if(bool){
document.getElementById(cehckboxId).style.display = 'none';
}
else {
document.getElementById(cehckboxId).style.display = 'block';
}
}
You may want to wrap the checkbox with a div and hide the container also to include the label.
To do it server-side, I would rely on a querystring parameter. Have the parent page load the child page by appending ?inframe=1. Then check for that value in your Page_Load.

Response.Redirect to new window

I want to do a Response.Redirect("MyPage.aspx") but have it open in a new browser window. I've done this before without using the JavaScript register script method. I just can't remember how?
I just found the answer and it works :)
You need to add the following to your server side link/button:
OnClientClick="aspnetForm.target ='_blank';"
My entire button code looks something like:
<asp:LinkButton ID="myButton" runat="server" Text="Click Me!"
OnClick="myButton_Click"
OnClientClick="aspnetForm.target ='_blank';"/>
In the server side OnClick I do a Response.Redirect("MyPage.aspx"); and the page is opened in a new window.
The other part you need to add is to fix the form's target otherwise every link will open in a new window. To do so add the following in the header of your POPUP window.
<script type="text/javascript">
function fixform() {
if (opener.document.getElementById("aspnetForm").target != "_blank") return;
opener.document.getElementById("aspnetForm").target = "";
opener.document.getElementById("aspnetForm").action = opener.location.href;
}
</script>
and
<body onload="fixform()">
You can use this as extension method
public static class ResponseHelper
{
public static void Redirect(this HttpResponse response, string url, string target, string windowFeatures)
{
if ((String.IsNullOrEmpty(target) || target.Equals("_self", StringComparison.OrdinalIgnoreCase)) && String.IsNullOrEmpty(windowFeatures))
{
response.Redirect(url);
}
else
{
Page page = (Page)HttpContext.Current.Handler;
if (page == null)
{
throw new InvalidOperationException("Cannot redirect to new window outside Page context.");
}
url = page.ResolveClientUrl(url);
string script;
if (!String.IsNullOrEmpty(windowFeatures))
{
script = #"window.open(""{0}"", ""{1}"", ""{2}"");";
}
else
{
script = #"window.open(""{0}"", ""{1}"");";
}
script = String.Format(script, url, target, windowFeatures);
ScriptManager.RegisterStartupScript(page, typeof(Page), "Redirect", script, true);
}
}
}
With this you get nice override on the actual Response object
Response.Redirect(redirectURL, "_blank", "menubar=0,scrollbars=1,width=780,height=900,top=10");
Contruct your url via click event handler:
string strUrl = "/some/url/path" + myvar;
Then:
ScriptManager.RegisterStartupScript(Page, Page.GetType(), "popup", "window.open('" + strUrl + "','_blank')", true);
Because Response.Redirect is initiated on the server you can't do it using that.
If you can write directly to the Response stream you could try something like:
response.write("<script>");
response.write("window.open('page.html','_blank')");
response.write("</script>");
The fixform trick is neat, but:
You may not have access to the code
of what loads in the new window.
Even if you do, you are depending on
the fact that it always loads, error
free.
And you are depending on the fact
that the user won't click another
button before the other page gets a
chance to load and run fixform.
I would suggest doing this instead:
OnClientClick="aspnetForm.target ='_blank';setTimeout('fixform()', 500);"
And set up fixform on the same page, looking like this:
function fixform() {
document.getElementById("aspnetForm").target = '';
}
You can also use in code behind like this way
ClientScript.RegisterStartupScript(this.Page.GetType(), "",
"window.open('page.aspx','Graph','height=400,width=500');", true);
This is not possible with Response.Redirect as it happens on the server side and cannot direct your browser to take that action. What would be left in the initial window? A blank page?
popup method will give a secure question to visitor..
here is my simple solution: and working everyhere.
<script type="text/javascript">
function targetMeBlank() {
document.forms[0].target = "_blank";
}
</script>
<asp:linkbutton runat="server" ID="lnkbtn1" Text="target me to blank dude" OnClick="lnkbtn1_Click" OnClientClick="targetMeBlank();"/>
<asp:Button ID="btnNewEntry" runat="Server" CssClass="button" Text="New Entry"
OnClick="btnNewEntry_Click" OnClientClick="aspnetForm.target ='_blank';"/>
protected void btnNewEntry_Click(object sender, EventArgs e)
{
Response.Redirect("New.aspx");
}
Source: http://dotnetchris.wordpress.com/2008/11/04/c-aspnet-responseredirect-open-into-new-window/
If you can re-structure your code so that you do not need to postback, then you can use this code in the PreRender event of the button:
protected void MyButton_OnPreRender(object sender, EventArgs e)
{
string URL = "~/MyPage.aspx";
URL = Page.ResolveClientUrl(URL);
MyButton.OnClientClick = "window.open('" + URL + "'); return false;";
}
You can also use the following code to open new page in new tab.
<asp:Button ID="Button1" runat="server" Text="Go"
OnClientClick="window.open('yourPage.aspx');return false;"
onclick="Button3_Click" />
And just call Response.Redirect("yourPage.aspx"); behind button event.
I always use this code...
Use this code
String clientScriptName = "ButtonClickScript";
Type clientScriptType = this.GetType ();
// Get a ClientScriptManager reference from the Page class.
ClientScriptManager clientScript = Page.ClientScript;
// Check to see if the client script is already registered.
if (!clientScript.IsClientScriptBlockRegistered (clientScriptType, clientScriptName))
{
StringBuilder sb = new StringBuilder ();
sb.Append ("<script type='text/javascript'>");
sb.Append ("window.open(' " + url + "')"); //URL = where you want to redirect.
sb.Append ("</script>");
clientScript.RegisterClientScriptBlock (clientScriptType, clientScriptName, sb.ToString ());
}
Here's a jQuery version based on the answer by #takrl and #tom above. Note: no hardcoded formid (named aspnetForm above) and also does not use direct form.target references which Firefox may find problematic:
<asp:Button ID="btnSubmit" OnClientClick="openNewWin();" Text="Submit" OnClick="btn_OnClick" runat="server"/>
Then in your js file referenced on the SAME page:
function openNewWin () {
$('form').attr('target','_blank');
setTimeout('resetFormTarget()', 500);
}
function resetFormTarget(){
$('form').attr('target','');
}
I used Hyperlink instead of LinkButton and it worked just fine, it has the Target property so it solved my problem. There was the solution with Response.Write but that was messing up my layout, and the one with ScriptManager, at every refresh or back was reopening the window. So this is how I solved it:
<asp:HyperLink CssClass="hlk11" ID="hlkLink" runat="server" Text='<%# Eval("LinkText") %>' Visible='<%# !(bool)Eval("IsDocument") %>' Target="_blank" NavigateUrl='<%# Eval("WebAddress") %>'></asp:HyperLink>
You may want to use the Page.RegisterStartupScript to ensure that the javascript fires on page load.
you can open new window from asp.net code behind using ajax like I did here
http://alexandershapovalov.com/open-new-window-from-code-behind-in-aspnet-68/
protected void Page_Load(object sender, EventArgs e)
{
Calendar1.SelectionChanged += CalendarSelectionChanged;
}
private void CalendarSelectionChanged(object sender, EventArgs e)
{
DateTime selectedDate = ((Calendar) sender).SelectedDate;
string url = "HistoryRates.aspx?date="
+ HttpUtility.UrlEncode(selectedDate.ToShortDateString());
ScriptManager.RegisterClientScriptBlock(this, GetType(),
"rates" + selectedDate, "openWindow('" + url + "');", true);
}
None of the previous examples worked for me, so I decided to post my solution. In the button click events, here is the code behind.
Dim URL As String = "http://www.google/?Search=" + txtExample.Text.ToString
URL = Page.ResolveClientUrl(URL)
btnSearch.OnClientClick = "window.open('" + URL + "'); return false;"
I was having to modify someone else's response.redirect code to open in a new browser.
I used this approach, it doesn't require you to do anything on the popup (which I didn't have access to because I was redirecting to a PDF file). It also uses classes.
$(function () {
//--- setup click event for elements that use a response.redirect in code behind but should open in a new window
$(".new-window").on("click", function () {
//--- change the form's target
$("#aspnetForm").prop("target", "_blank");
//--- change the target back after the window has opened
setTimeout(function () {
$("#aspnetForm").prop("target", "");
}, 1);
});
});
To use, add the class "new-window" to any element. You do not need to add anything to the body tag. This function sets up the new window and fixes it in the same function.
I did this by putting target="_blank" in the linkbutton
<asp:LinkButton ID="btn" runat="server" CausesValidation="false" Text="Print" Visible="false" target="_blank" />
then in the codebehind pageload just set the href attribute:
btn.Attributes("href") = String.Format(ResolveUrl("~/") + "test/TestForm.aspx?formId={0}", formId)
HTML
<asp:Button ID="Button1" runat="server" Text="Button" onclick="Button1_Click" OnClientClick = "SetTarget();" />
Javascript:
function SetTarget() {
document.forms[0].target = "_blank";}
AND codebehind:
Response.Redirect(URL);

Categories