Javascript calling c# function

Hi all. Tried to do a search on this one, but didnt know exactly how to word it so I wasn't able to find much info on what I wanted to do.

Overview of what I'm trying to do.

Version: asp.net 1.1

I have a crystal report that takes a long time to run and impatient users click the submit button over and over mucking up the system.

I've been trying to create a "processing your request" type progress bar that will pretty much inform the user to chill out and let the report run its course. (I'm also going to disable the buttons when I get that far).

I've gotten the bar to run, but for the life of me cannot call the ProcessReport() from the javascript and its driving me nuts.

Javascript:

???? Here's where I'm hitting the ceiling. What do I call here to run the ProcessReport() c# function in the code behind?

I've tried __doPostBack and <% ProcessReport(); %> (which unfortunately runs the process as soon as it's encountered so thats not good) and neither have seemed to run it for some reason.

my Form info:
<form id="wwv_flow" action="wwv_flow.accept" method="post" name="wwv_flow" runat="server">

Any help would be greatly appreciated.

Thanks

Frank

Re: Javascript calling c# function

There is really no way to do that, as client-side processing and server-side processing are 2 different things.

I posted this little control a while back that works asynchroneously and might help you out:
http://forums.asp.net/1108756/ShowPost.aspx

Or you might take a look here for an AJAX solution:
http://ajax.asp.net/docs/tutorials/PartialPageUpdateTutorials.aspx

NC...

Re: Javascript calling c# function

For the button that generates the report (in Page_Load):

Button1.Attributes.Add("onclick", "this.style.display = 'none'; alert('Hold your horses!');")

Hope this helps! Please mark the helpful post(s) as Answer.

Re: Javascript calling c# function

NC,

Thanks for the iinfo on the control and the Ajax info. I have no idea what that is yet, I've seen references to it all over but figured it was a paid for control.

I'll let you know how it works out.

Thanks again,

Frank

Re: Javascript calling c# function

Looking at the control I have one question before I try it. I think i've tried something similar to this, but not sure.

When the "process report" button is clicked, a crystal report is generated and saved to the server as a PDF. Then the process redirects the user to that file which loads into an adobe acrobat reader that is displayed outside of the browser (in browser display is turned off).

So I'm not sure if this will work for what I'm trying.

Right now what happens is that the progress bar pops up when the button is clicked, but after the redirect I can't seem to get it to stop.

What I've thought to do is create the file, store the value in a hidden field and on the post back, if that field is populated, turn off the progress bar and then do a javascript redirect. Which, I would expect, would do the same thing.

Not sure how well that would work though, im not as familar with javascript, so not sure how well that would work.

Frank

Re: Javascript calling c# function

I doubt if the control will work for that, as it works asynchroneously on a page object.

While the Page object is doing the server-side processing, the control is visible. As soon as the server-side processing is completed, the control is hidden.

You'd have to have to place it into the PDF doc that you are redirecting to. This might work however.

Instead of redirecting to the PDF doc, redirect to this dummy page which only contains an IFrame to display the PDF doc.

Call by:
Response.Redirect("PdfDisplayer.aspx?PdfDoc=" + pdfDocUrl);

///////////////////////////
// aspx file:
///////////////////////////

<%@ Page language="c#" Codebehind="PdfDisplayer.aspx.cs" AutoEventWireup="false" Inherits="Tester.PdfDisplayer" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
  <title>PDF Displayer</title>
  <meta content="Microsoft Visual Studio .NET 7.1" name="GENERATOR">
  <meta content="C#" name="CODE_LANGUAGE">
  <meta content="JavaScript" name="vs_defaultClientScript">
  <meta content="http://schemas.microsoft.com/intellisense/ie5" name="vs_targetSchema">
  <base target="_self">
</HEAD>
<body bottommargin="0" topmargin="0">
  <form id="Form1" method="post" runat="server">
   <iframe id="displayIFrame" frameborder="0" height="100%" runat="server" src="" width="100%">
   </iframe>
  </form>
</body>
</HTML>

///////////////////////////
// aspx.cs file:
///////////////////////////

protected System.Web.UI.HtmlControls.HtmlGenericControl displayIFrame;

private void Page_Load(object sender, System.EventArgs e)
{
string frameSource = this.Request["PdfDoc"];
this.displayIFrame.Attributes.Add("src", frameSource);
}

NC...

Re: Javascript calling c# function

Here is an old .NET 1.1 function I wrote a while back which disables a Button after it is clicked (only if it passes client-side validation). The server-side code for the button will still run though and the button will re-enable after the postback completes. It is overloaded to allow the passing of a message which will override the message that exists on the button. Here is the function:

private void DisableButtonOnClientClick(ref Button control, string message)
{
	control.Attributes["onclick"] = "if(typeof(Page_ClientValidate)=='undefined'||(typeof(Page_ClientValidate)=='function'&&Page_ClientValidate())){this.disabled=true;" + (message != null ? "this.value='" + message + "';" : "") + GetPostBackEventReference(control) + ";return false;}";
}
private void DisableButtonOnClientClick(ref Button control)
{
	DisableButtonOnClientClick(ref control, null);
}

Just call this function on each page load for any button you want it attached to like this:

DisableButtonOnClientClick(ref this.Button1, "...Loading...");

Re: Javascript calling c# function

Doesn't disabling the button cause the server-side event handler to not fire?

Re: Javascript calling c# function

Normally it does. That is why I came up with this solution awhile back. It will disable the button client-side after it is clicked (ONLY if client-side validation passes) but it will still fire the server-side button event. It will remain disabled until the button's server side code completes and the page completes its post back.

Re: Javascript calling c# function

I wrote a similar function in .NET 2.0 which accounts for validation groups. If someone wants it I will dig it up and post it as well.

Re: Javascript calling c# function

Based on my own experience, Im not so sure disabling the submit button is a good idea. It has caused so many unexpected problems in the past.

What if you have validation on your form onsubmit?

Re: Javascript calling c# function

The button is only disabled if client-side validation passes. If client-side validation passes then the button is disabled and the server-side button click event is fired. The disabled status (along with the textual change on the button's value property) will go away after the server-side code runs and the page finishes its postback.

Re: Javascript calling c# function

No need to repeat yourself. I'd love to see an in-production example of this...

Re: Javascript calling c# function

Unfortunately I cannot provide links to my company's internal systems [:)]

Re: Javascript calling c# function

James,

I can't see how that will work as
1. You're disabling it AFTER the server-side button event, so it is not going to take affect until AFTER the next button click.
2. What is the use of checking for client-side validation AFTER the server-side event has happened, as it would have already happened for the server-side event to fire.

This will work, though I agree with Josh that disabling buttons could cause problems.

private void Page_Load(object sender, System.EventArgs e)
{
StringBuilder javaScript = new StringBuilder();
javaScript.Append("if ( typeof(Page_ClientValidate) == 'function' )");
javaScript.Append("{ ");
javaScript.Append(" if ( Page_ClientValidate() == false )");
javaScript.Append(" return false;");
javaScript.Append("} ");
javaScript.Append("this.value = 'Please wait...';");
javaScript.Append("this.disabled = true;");
javaScript.Append(Page.GetPostBackEventReference(Button1, string.Empty));
javaScript.Append(";");

Button1.Attributes.Add("onclick", javaScript.ToString());
}

private void Button1_Click(object sender, System.EventArgs e)
{
// Emulate a lengthy process...
TimeSpan waitTime = new TimeSpan(0, 0, 0, 10);
System.Threading.Thread.Sleep(waitTime);

Response.Write("Button1_Click fired<br>");
}

NC...

Re: Javascript calling c# function

The button is not disabled AFTER the server-side button event. It is disabled BEFORE the server-side button event. When the button is clicked, here is the order of operation for this function:

If client-side validation DOES NOT exist or if client-side validation DOES exist AND client-side validation passes, then...
Disable the button client-side
Change button text
DO POSTBACK which executes the server-side button event code

The button will remain disabled until the server-side code post back is complete.

I've included a very basis .NET 1.1 example below. You can test it out easily. I put a 2.5 second sleep in the button server-side code to demonstrate the temporary disabling. You can keep or remove the RequiredFieldValidator on the page as it works with or without client-side validation.

ASPX

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
	<HEAD>
		<title>WebForm1</title>
		<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
		<meta name="CODE_LANGUAGE" Content="C#">
		<meta name="vs_defaultClientScript" content="JavaScript">
		<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
	</HEAD>
	<body>
		<form id="Form1" method="post" runat="server">
			<asp:TextBox id="TextBox1" runat="server" />
			<asp:Button id="Button1" runat="server" Text="Submit" />
			<asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" ErrorMessage="Field is required." ControlToValidate="TextBox1" />
		</form>
	</body>
</HTML>

ASPX.cs

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace TestSolution
{
	/// <summary>
	/// Summary description for WebForm1.
	/// </summary>
	public class WebForm1 : System.Web.UI.Page
	{
		protected System.Web.UI.WebControls.TextBox TextBox1;
		protected System.Web.UI.WebControls.RequiredFieldValidator RequiredFieldValidator1;
		protected System.Web.UI.WebControls.Button Button1;
	
		private void Page_Load(object sender, System.EventArgs e)
		{
			DisableButtonOnClientClick(ref this.Button1, "...Loading...");
		}
		private void DisableButtonOnClientClick(ref Button control, string message)
		{
			control.Attributes["onclick"] = "if(typeof(Page_ClientValidate)=='undefined'||(typeof(Page_ClientValidate)=='function'&&Page_ClientValidate())){this.disabled=true;" + (message != null ? "this.value='" + message + "';" : "") + GetPostBackEventReference(control) + ";return false;}";
		}
		private void DisableButtonOnClientClick(ref Button control)
		{
			DisableButtonOnClientClick(ref control, null);
		}
		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.Button1.Click += new System.EventHandler(this.Button1_Click);
			this.Load += new System.EventHandler(this.Page_Load);
		}
		#endregion
		private void Button1_Click(object sender, System.EventArgs e)
		{
			if (Page.IsValid)
			{
				System.Threading.Thread.Sleep(2500);
			}
		}
	}
}

Re: Javascript calling c# function

Sorry, in your original post I missed the call to DisableButtonOnClientClick in the Page_Load event handler which will make your code operate almost identical to what I posted.

NC...

Re: Javascript calling c# function

Just like I already mentioned....

What if you have your own custom validation on the form onsubmit? If that validation fails, you are left there with a disabled button and no way to submit the form.

Re: Javascript calling c# function

Ho hum. Here is the same example page with a custom validator on it. If custom validation fails it does not leave the button disabled. Whether the custom validation is client-side or server-side it doesn't matter. Are you even testing the code or should I just stop providing examples?

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
	<HEAD>
		<title>WebForm1</title>
		<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
		<meta name="CODE_LANGUAGE" Content="C#">
		<meta name="vs_defaultClientScript" content="JavaScript">
		<meta name="vs_targetSchema" content="http://schemas.microsoft.com/intellisense/ie5">
		<script type="text/javascript">
			function doCustomValidation(sender,args) {
				args.IsValid = (document.getElementById('<%=TextBox1.ClientID%>').value != '');
			}
		</script>
	</HEAD>
	<body>
		<form id="Form1" method="post" runat="server">
			<asp:TextBox id="TextBox1" runat="server" />
			<asp:Button id="Button1" runat="server" Text="Submit" />
			<asp:RequiredFieldValidator id="RequiredFieldValidator1" runat="server" ErrorMessage="Field is required." ControlToValidate="TextBox1" />
			<asp:CustomValidator ID="CustomValidator1" Runat="server" ErrorMessage="Custom validation failed." ClientValidationFunction="doCustomValidation" />
		</form>
	</body>
</HTML>

Re: Javascript calling c# function

Dude, I don't need to test the code becuase, as mentioned before, I have already been down this path!

I am not talking about this CustomValidator bullcrap. I am talking about hard coding your own form onsubmit validation. Not with any .NET validators or anything like that, that is all rubbish. In several of my web apps, I have my own validation that I put on the form onsubmit that does many different things. Your code will break that, guaranteed. I can say that with confidence withotu testing. Perhaps you should test your code with that and see for yourself!

I am done arguing with you about this. It is a bad idea to disable the submit button. Period.

Regards...