Firing Server Side Event from jQuery - __EVENTARGUMENT Does not Exist - asp.net

I am trying to fire a form submit via jQuery and have a particular server side event fire.
Client Side Code:
$("input[name=__EVENTARGUMENT]").val("SomeArg");
form = $("body form");
form.submit();
Server Side Code:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
if (Request["__EVENTARGUMENT"] == "SomeArg")
{
//do some stuff
}
}
}
The problem is, the "__EVENTARGUMENT" hidden input does not exist. I discovered that if I add an ASP.net server control dropdownlist with autopostback = true, the EVENTARGUMENT hidden input is created. Is there a cleaner way to have ASP.net create these hidden inputs, and allow me to get their values server side without adding controls I do not actually need on the page?

Add asp.net HiddenField control to the page
But you will have a problem which is to get this control id, which as.net generates automatically, you can solve this using the ClientID property for the hidden field like this article mentions

Related

ASP.Net web application - server side canceling Submit PostBackUrl if not(!) Page.IsValid

I have a web application, and the submit uses the PostBackUrl to display data if the form is valid.
I need to use different (server side) validation groups, depending on what radiobutton is selected. That is, manually call
Page.Validate('ValidationGroupA').
The validation itself is working fine, in terms of Page.IsValid correctly assigned true or false.
However, if the page is not valid, the page redirects to the page specified by PostBackUrl on the submit button, where the page is found not to be valid, and the client redirected back with:
if (!PreviousPage.IsValid){Response.Redirect("DataEntryPage.aspx");})
However, by getting to here and back again, all form data is lost, and the relevant validation controls and summaries are not displayed.
Is there any equivalent of JavaScripts evt.preventDefault() or some other way, once it is detected validation has failed after a manual call to Page.Validate to post the form back with appropriate validation errors displayed?
Use ASP.Net Client Side Validation.
jQuery Code (call this on onclick of submit button):
$("#SubmitButtonID").click(function (e) {
Page_ClientValidate('ValidationGroupA');
if (!Page_IsValid)
{
e.preventDefault();
}
});
I ended up removing the PostBackUrl directive, and using an onclick event for the submit button
protected void Submit_Click(object sender, EventArgs e)
{
if (chartTypeRadio.Text != "bolus") { Page.Validate("age"); }
if (Page.IsValid) { Server.Transfer("~/PatientSpecificDrugChart.aspx", true); }
}

click event for HTML dynamic button

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
}

asp.net prevent events from being raised

I have a control (.ascx) that sits on a page (.aspx). Within that control there's a asp.net update panel that encompasses everything for that control. When the control does a post back it automatically raises all the events from the control plus all the events from the page it sits on. This is causing significant performance problems.
Is there any way to stop the events from being raised that reside on the page that the control is sitting on?
Thanks
Check the ScriptManager.IsInAsyncPostBack Property.
Here is the sample code:
protected void Page_Load(object sender, EventArgs e)
{
if (Page.IsPostBack)
{
// get a reference to ScriptManager and check if we are in a partial postback
if (ScriptManager.GetCurrent(this.Page).IsInAsyncPostBack)
{
// partial (asynchronous) postback occured
// insert Ajax custom logic here
}
else
{
// regular full page postback occured
// custom logic accordingly
}
}
}

how can I reload an update panel onclient side using javascript?

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.

Hide/Show controls with AJAX

I am using an ASP.NET AJAX-Enabled Web application (ASP.NET 2.0 and AJAX Toolkit 1.0)
that contains one button and 2 UpdatePanels (UpdatePanel_1 and UpdatePanel_2)
The button is registered with RegisterAsyncPostBackControl in the ScriptManager object
UpdatePanel_1 is in "Conditional" update mode and contains a TextBox.
UpdatePanel_2 is in "Always" update mode and contains another TextBox
When the button is pressed its handler calls UpdatePanel_1.Update() that updates the value of the TextBox based on a randomly selected value in a list;
Also the UpdatePanel_2's TextBox is being updated automatically , also without page refresh
Based on the value of a boolean ViewState variable I would also like to hide/show the UpdatePanels alternatively but
I get the error :
"Sys.InvalidOperationException: COuld not find UpdatePanel with ID 'UpdatePanel_2' (or UpdatePanel_1).
If it is being updated dynamically then it must be inside another UpdatePanel"
How can it be done without adding extra wrapping UpdatePanels?
protected void Page_Load(object sender, EventArgs e)
{
ScriptManager1.RegisterAsyncPostBackControl(Button1);
if (!IsPostBack)
{
Visibility = true;
}
UpdatePanel_1.Visible = !Visibility;
UpdatePanel_2.Visible = Visibility;
Visibility = !Visibility;
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Panel1.Visible)
UpdatePanel_1.Update();
}
protected bool Visibility
{
get
{
return (bool)(ViewState["Visibility"] ?? true);
}
set
{
ViewState["Visibility"] = value;
}
}
The problem is that invisible controls aren't rendered to the client. So then trying to make them visible isn't going to work because as far as the client is concerned, they don't exist.
Try using style="display:none", or use different CSS classes and styles for visible and invisible panels, rather than setting visible=false;
You can invisible, or visible controls is child of updatepanel, not invisible, visible updatepanel, I try use updatemode = conditional but error, and then I visible controls add to updatepanel. Hopy help you
Thanks everybody post

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