I have an ASP.net application with an aspx page.
In Page_Load event of the aspx page, I'm handling some code which is based on the value of a hidden variable from the javascript(assigning result of javascript to hidden variable).
I am calling the javascript in Page_Load of the child page, and in the immediate statement, I'm making use of the hidden variable value for processing. When I access hidden variable value, I'm getting default value only.
Please suggest me any of handling the scenario. I need to execute the javascript and get the result into the hidden variable. Both in need to occur in Page_Load event only.
Hidden Variable declaration:
<asp:HiddenField runat='server' ID='hdnDate' Value='0' />
Javscript:
function getCDate() {
var nowDate = new Date();
var curr_month = nowDate.getUTCMonth();
curr_month ++;
var dt = curr_month + "/" + nowDate.getUTCDate() + "/" +nowDate.getFullYear()+ " " + nowDate.getUTCHours()+":" +nowDate.getUTCMinutes()+":" +nowDate.getUTCSeconds();
document.getElementById("ctl00_ContentPlaceHolder1_hdnDate").value = dt;
return true;
}
Page_Load method in code behind file:
protected void Page_Load(object sender, EventArgs e)
{
Page.ClientScript.RegisterStartupScript(this.GetType(), "alert", "getCDate();", true);
DateTime dt=Convert.ToDateTime(hdnDate.Value);
dt.AddDays(10); //getting error here because dt contains01/01/0001
}
You cannot call javascript in Page_Load. It is client side thing so should come from browser only. You can check if page is postback using IsPostBack property of Page object like this:
if(IsPostBack)
{
//this is coming from browser so you javascript might have been
//called and proper value set in hidden field.
}
Javascript is run on the client side, so can't run in the Page_Load event on the Server.
From the looks of your code, I'm pretty sure you don't need javascript, you can just put the value into a SessionVariable as:
Session.Add("DateRendered", DateTime.Now.AddDays(10).ToString("MM/dd/YYYY"));
And then retrieve it later. ASP.net takes care of storing it in the Request/Response.
RegisterStartupScript will register your block of script for the next page load.
if you just want some value to be transferred to .cs page write a static method on the .cs and call it from javascript using PageMethods.MethodName();
Related
I am using a jQuery editor and when the user hits the submit button i put the content into asp.net Panel control as html and then when i render this Panel the html i added is not
retrieved.
function MoveData() {
var sHTML = $('#summernote_1').code();
// dvFrontPageHtml is asp.net Panel
$('[id*=dvFrontPageHtml]').html(sHTML);
setTimeout(function () {
javascript: __doPostBack('ctl00$ctl00$ContentPlaceHolderBody$ContentPlaceHolderBody$lnkSave', '');
}, 10000);
return false;
}
System.Text.StringBuilder sb = new System.Text.StringBuilder();
System.IO.StringWriter stWriter = new System.IO.StringWriter(sb);
System.Web.UI.HtmlTextWriter htmlWriter = new System.Web.UI.HtmlTextWriter(stWriter);
dvFrontPageHtml.RenderControl(htmlWriter);
string Message = sb.ToString();
The message does not returning the html added.
I dont want to use jQuery ajax call as of now.
Any suggestions
without seeing all the relevant code its hard to pinpoint the problem.
but im pretty sure you are trying to find an ASP.net control by its serverside ID from clientside.
dvFrontPageHtml is the Controls ID by which asp.net identifies it, and unless you explicitly tell ASP.Net otherwise, it will generate a different ID for the control to be used by scripts at clientside
you need to retrieve the panel's clientside ID thats being generated for it by asp.net
you do it by a preprocessor directive <%=dvFrontPageHtml.ClientID%>:
$('[id*=<%=dvFrontPageHtml.ClientID%>]').html(sHTML);
alternatively, if you want the clientside ID to be same as the serverside ID, you can set the control's attribute ClientIDMode="Static".
UPDATE:
from your comment it seems the problem is elsewhere. what comes to mind, is that RenderControl() takes the control as it was when sent to the client in the Response. but the control is not being submitted to the server in next Request, so you will not be able to retrieve its altered html.
what you can do as a workaround, is hook into ASP.NET's build in postback mechanism, and submit the panel's html as a custom event argument:
for the example, lets assume this is our html:
<asp:Panel ID="dvFrontPageHtml" runat="server" ClientIDMode="Static">test</asp:Panel>
<asp:Button ID="BT_Test" runat="server" Text="Button"></asp:Button>
this will be our javascript:
$(function(){
// add custom event handler for the submit button
$("#<%=BT_Test.ClientID%>").click(function (ev) {
//prevent the default behavior and stop it from submitting the form
ev.preventDefault();
//alter the panels html as you require
var sHTML = $('#summernote_1').code();
$('[id*=dvFrontPageHtml]').html(sHTML);
//cause a postback manually, with target = BTCLICK and argument = panel's html
__doPostBack('BTCLICK', $('[id*=dvFrontPageHtml]').outerHTML());
});
});
and here we capture the postback on serverside:
//we monitor page load
protected void Page_Load(object sender, EventArgs e)
{
string Message;
//check if its a postback
if (IsPostBack)
{
//monitor for our custom target "BTCLICK"
if (Request.Form["__EVENTTARGET"].CompareTo("BTCLICK") == 0)
{
// retrieve the panels html from the event argument
Message = Request.Form["__EVENTARGUMENT"];
}
}
}
I'm developing a C# ASP.NET application under VS2010. I want to generate a dynamic table by writing HTML text into a literal, including dynamically inserted buttons on my table. I know how to create dynamic ASP.NET controls, but I have a small problem with dynamic HTML controls. I've created an HTML button but I don't know how to give it a server-side click function.
Can I create dynamic ASP.NET controls and insert them in my literal? How can I get a dynamically created button to trigger a server-side event?
I've used OnServerClick property for defining my server side function but it has no effect, how can I use this value?
If you want post back on your button click, you will have to add __doPostBack function on it's onclick event, for this you can add a button like
StringBuilder dynamicHtml = new StringBuilder();
dynamicHtml.Append("Your Html Code");
dynamicHtml.Append("<input type='button' id='btn1' name='btn1' onclick='__doPostBack(\'btn1\',\'\')' value='Click Here' />");
when you click on it, it will post back, and you can check Request.Form["__EVENTTARGET"] to find who post back the page.
By checking Request.Form["__EVENTTARGET"] in Page_Load event handler, you can call your any server side method like
protected void Page_Load(object sender, EventArgs e)
{
var eventTarget = Request.Form["__EVENTTARGET"].ToString();
if(eventTarget == "btn1")
{
CallMethod1();
}
}
private void CallMethod1()
{
//Code which you want to run
}
Following is the scenario I am facing, I have a aspx page in which I have added my ascx user control, I also have a <a href control which call a js function to open a aspx popup.
when I open the popup, I need to send the data present in the ascx control to my popup. can you please guide me what method can I use to achieve this other than using session, as the data can be updated in many different places hence maintaining in session will be difficult.
Thanks
try with these syntaxe ( RegisterStartupScript + window.open)
ScriptManager.RegisterStartupScript(Page, Page.GetType(), "newWindow", "window.open('Test.aspx?ID=" + _cId + "','_blank','status=1,toolbar=0,menubar=0,location=1,scrollbars=1,resizable=1,width=30,height=30);", false);
You said that you are using a js function to open the aspx popup.
then it is simple.
1. Read the Data from the controls of the User control by using javascript
var variable1 = document.getElementByID("ControlId").value;
var variable2 = document.getElementByID("ControlId").value;
2. Pass this data as query string to the next page
window.open("http://www.w3schools.com?id=" + variable1 + "&name=" + variable2);
You can read this data from querystring from the next page
If you cant sent data as querystring , can try some other ways
1. Try to post the form to the other page using target="_blank".
we can dynamically change the form action if needed.
OR
2. Make use of the window.opener object from the popup to read the data from controls the opener page.
var variable1 = window.opener.getElementById("ControlId").value
Create a hidden variable in your ascx.
<asp:HiddenField runat="server" ID="hdnId" />
On page load of ascx set the value to be sent to the hidden variable
protected void Page_Load(object sender, EventArgs e){
hdnId.Value = <value to be sent to pop-up>;
}
Register a ajax manager in the code behind.
protected override void OnInit(EventArgs e)
{
RadAjaxManager.GetCurrent(this.Page).ClientEvents.OnRequestStart = "ajaxMngr_RequestStart;";
base.OnInit(e);
}
In the ajaxMngr_RequestStart() JS
function ajaxMngr_SA_RequestStart(sender, args) {
var oPatId = "<%=hdnSendPatId.Value %>";
//add code to open the pop-up, add oPatId as part of the URL
}
}
I use Telerik, which makes helps a lot in managing pop-ups. Let me know, if this helps.
Cheers!
I have a gridview button that I programmatically created and I want to load an update panel on the client side with the sent data. I have a hidden value field that gets its data on the click of the gridview button and the dropdownlist in my updatepanel depends on that value.
while calling __doPostBack directly will work, it's not a perfect solution because the name of that function is strictly speaking an implementation detail of the .Net framework.
A better solution is to use ClientScriptManager.GetPostBackEventReference, which gives you a more resilient interface to the same functionality. Do note that GetPostBackEventReference and GetCallBackEventReference are not the same thing - the former causes a page reload (partial or full, depending on how your UpdatePanels are set up), while the latter doesn't.
The easiest way to do this is to call __doPostBack from client side.
On client side button1_onclick method, calls:
__doPostBack('<%=UpdatePanel1.ClientID %>','Refresh:0,1,2'); //refresh update panel
On page behind add the following event handler to capture the post back call:
protected void UpdatePanel1_Load(object sender, EventArgs e)
{
string arg = Request.Form["__EVENTARGUMENT"];
if (string.IsNullOrEmpty(arg)) return;
if (arg.StartWith("Refresh")
{
//parse data first then do your thing here...
}
}
And of course don't forget to wire event to the above method:
protected void Page_Init(object sender, EventArgs e)
{
UpdatePanel1.Load += new EventHandler(UpdatePanel1_Load);
}
we use the __dopostback() method which simulates a postback and causes the updatepanel to refresh
__doPostBack('controlName','');
Don't forget that the control name is it's HTML ID (which may well contain dollars etc) and not just it's ASP.NET ID.
As far as I know you can either call this method and pass in the hidden value field, or the div that it is in.
I have a LinkButton that has to postback to perform some logic.
Once it is finished, instead of loading the page back up in the browser, I want to leave it alone and pop open a new window.
So far, the best idea I've had is to put the LinkButton in an UpdatePanel, and have it render some JavaScript out when it reloads, yet I think that is totally hacky. Also, if I recall right, JavaScript within a update panel won't run anyways.
Any other ideas?
Use LinkButton.PostBackUrl to set a different page to POST to, and some client script to get a new window (and the old target restored so that future postbacks work normally). The 2nd page can use PreviousPage to get access to any needed state from the original page.
<script runat="server">
void lnk_Click(object sender, EventArgs e) {
// Do work
}
</script>
<script type="text/javascript">
var oldTarget, oldAction;
function newWindowClick(target) {
var form = document.forms[0];
oldTarget = form.target;
oldAction = form.action;
form.target = target;
window.setTimeout(
"document.forms[0].target=oldTarget;"
+ "document.forms[0].action=oldAction;",
200
);
}
</script>
<asp:LinkButton runat="server" PostBackUrl="Details.aspx" Text="Click Me"
OnClick="lnk_Click"
OnClientClick="newWindowClick('details');" />
Here is the code:
protected void Button1_Click(object sender, EventArgs e)
{
// Do some server side work
string script = "window.open('http://www.yahoo.com','Yahoo')";
if (!ClientScript.IsClientScriptBlockRegistered("NewWindow"))
{
ClientScript.RegisterClientScriptBlock(this.GetType(),"NewWindow",script, true);
}
}
One thing you could try is to have your LinkButton OnClick event do its processing, then register a Page.ClientScript.RegisterStartupScript with the popup code, which will put some Javascript into the tag to fire off after the page loads. This should launch your new window after the processing completes.
EDIT: Reading your comment, I believe you can still use this approach, have your results stored in a session variable, and then have the popup page pull the results from there.