topic Re: Call JavaScript Function from C# .aspx .net app in .NET and the Esri JavaScript API Questions

Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sat, 02 May 2020 02:13:46 GMT

I have an aspx C# .net app that was written apart from me

I added a map component outside the FORM tags.

I am trying to find a trigger that AFTER the page loads where I can fire off a JavaScript Function....I am stuck and have tried a hundred different Google searches...

Is there an after Page Load that I can reference from the aspx page?

How can I call a Separate JS file Function that resides in the Solution from C# .net after some sort of trigger from the .net page

PLEASE HELP

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sat, 02 May 2020 02:41:07 GMT

Note: this is a stand alone JS page in the .net solution.....I need to call a function in the stand alone JS page after page load.

Re: Call JavaScript Function from C# .aspx .net app

Anonymous User — Sun, 03 May 2020 03:41:43 GMT

Hi jay kapalczynski‌,

Is that possible to share the solution?

Anyway, here is the tip.

And here is the onclientclieck event you can try. Button.OnClientClick Property (System.Web.UI.WebControls) | Microsoft Docs

If you want to perform customization only after page load, you can use LoadComplete event.

This is the life cycle of the aspx form.

ASP.NET Page Life Cycle Overview | Microsoft Docs

If you want to wireup the client event to particular control, you can perform by playing attributes properties of the control.

Another tip ->

If you need to perform scriptlet like that to get particular control client id and perfrom in javascript, the best way is to add the external js reference or script tag just before end of body tag </body>.

document.getElementById("<%=lbl_passwordStrength.ClientID%>").innerHTML = strength;

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:08:56 GMT

Thanks and that helps.....SO I am grabbing a session variable from the Page_LoadComplete and now need to pass this to an external js page. Its in the solution but not in the aspx etc.

js indexed from the Site.Master aspx page

    <script lang="javascript" src = "js/index.js" type="text/javascript"></script>‍‍

void Page_LoadComplete(object sender, EventArgs e)
   {
       // call your download function

       //Check if the Session value exists
       if (Session["ID"] != null)
       {
           string IDGUID = Session["ID"].ToString();
           TextBoxIDGUID.Text = IDGUID;
       }

      // Call a function in the index.js page referenced in the main aspx page      
      // I do want this to fire after page load NOT from a button
      // ????????
 }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:08:59 GMT

Trying this to call the JS Page

void Page_LoadComplete(object sender, EventArgs e)
    {
       ClientScript.RegisterStartupScript(GetType(), "Javascript", "javascript:Testreturn(); ", true);
    }‍‍‍‍‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

Anonymous User — Sun, 12 Dec 2021 09:09:02 GMT

Hi jay kapalczynski‌,

I got what you are trying to do now.

To call js function after aspx page is fully loaded, the best place is before the end of body tag by adding js script.

<body>


<script type="text/javascript">
//
// try by checking page load event finish and call your js method here
    </script>
</body>‍‍‍‍‍‍‍‍

In the js script , if you are using arcgis js library, you can use dojo dom ready package to track whether page load is finished.

https://dojotoolkit.org/reference-guide/1.10/dojo/domReady.html

In pure js way, this stackoverflow discussion can help you.

Pure JavaScript equivalent of jQuery's $.ready() - how to call a function when the page/DOM is ready for it - Stack Over…

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:09:05 GMT

Thanks for the info....trying to read through it....confusing but trying...

At the top of the Site.Master I have the JS reference

At the bottom of the Site.Master I have the following code...

I get the alert saying "alert here" so I received conformation the page was loaded.

I then try and call a JS function that exists in the location of the reference (external JS File)

I do NOT get that alert...so I am not getting there...

ALTHOUGH I get the Alert from the domReady in the JS page -- alert("In the JS file");

ALTHOUGH I can get the Alert for the ready function and CALL the myFunction() and get its alert

BUT this is simply being done on Load of the Pages....

I need to call a functions separate from a Page Load success.....is it even possible to call a JS function directly from C# aspx .net????

What am I missing here.....going back to read your post to try and figure this out. Maybe I am totally confused here....Client and Server is hard to work with....uggggg

 <!-- TOP OF THE SITE.MASTER  -->

    <link rel="stylesheet" href="https://js.arcgis.com/4.14/esri/themes/light/main.css"/>
    <script src="https://js.arcgis.com/4.14/"></script>
    <script lang="javascript" src = "js/index.js" type="text/javascript"></script>




 <!-- BOTTOM OF THE SITE.MASTER  -->
    <script>
        function docReady(fn) {
            // see if DOM is already available
            if (document.readyState === "complete" || document.readyState === "interactive") {
                // call on next available tick
                setTimeout(fn, 1);
            } else {
                document.addEventListener("DOMContentLoaded", fn);
            }
        }  
        docReady(function () {
            // DOM is loaded and ready for manipulation here
            alert("alert here");

            // NOW CALL MY JS FUNCTION IN THE index.js external file
            myFunction();

        });
    </script>


</body>

</html>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

EXTERNAL JS FILE Referenced above.

require([
    "esri/Map", "esri/views/MapView", "esri/layers/FeatureLayer",
    "dojo/ready", "dojo/domReady!"
], function (Map, MapView, FeatureLayer,
   ready
) {
        "use strict";


    function myFunction(){
        alert("In myFunction in the JS Page via C# Call");
    }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

    alert("In the JS file");

    ready(function () {
        alert("In the function called by the Ready Function");
        myFunctionFromReady();
    });

    function myFunctionFromReady(){
        alert("In myFunction in the JS Page via JS Ready function Call");
    }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Tue, 05 May 2020 16:24:06 GMT

Again this application is not mine and the developer is only using one page and hiding and making visible stuff....frustrating because this makes the page load not function the way I was expecting....Although it is doing what I want -- the way the app is built does not allow me to use the page load complete call.... no go for me....

I think all of this will work fine once I find a new trigger to run this code.

Back to the drawing board .... will be in touch soon....I think your help is sufficient but want to check a few things before we close this one and give you the credit...

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:09:07 GMT

Than Aung‌

I want to do this....not sure if I can

I can get the Alert and the value from "script" below (In the TrEdit.aspx.cs FILE seen below)

I would like to take that and pass it to an external Javascript function defined in the aspx page

Maybe this is whats causing my error below?

Maybe I cannot do this entirely?

ERROR:

VM187:1 Uncaught ReferenceError: myFunctionCSharp is not defined
at <anonymous>:1:13

Site.Master -- Notice context to MainContent referencing the second ASPX page below

The JS page is defined here on the Site.Master file....

<!-- SNIP -->

    <link rel="stylesheet" href="https://js.arcgis.com/4.14/esri/themes/light/main.css"/>
    <script src="https://js.arcgis.com/4.14/"></script>
    <script lang="javascript" src = "js/index.js" type="text/javascript"></script>

<!-- SNIP -->

</head>

<body class="home">

<!-- SNIP -->

        <main>
            <br />
            <br />
            <article>
                <form id="form1" runat="server">
                    <div id="content">
                        <h1>List</h1>
                        <h2 id="tagline"><i><%: Page.Title %></i></h2>
                        <asp:ContentPlaceHolder ID="MainContent" runat="server"></asp:ContentPlaceHolder>
                    </div>
                </form>
            </article>
        </main>‍‍‍‍‍‍‍‍‍‍‍‍‍

<!-- SNIP -->


</body>

</html>‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

TrEdit.aspx file - Notice the reference to the .aspx.cs page below

<%@ Page Title="" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true" CodeBehind="TrEdit.aspx.cs" Inherits="NW.Edit" MaintainScrollPositionOnPostback="true" %>


<asp:Content ID="Content1" ContentPlaceHolderID="MainContent" runat="server">‍‍‍‍

‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

TrEdit.aspx.cs FILE

I am trying to call the JavaScript function from here BECAUSE I cannot do it on the page load complete as I am not being sent to another page...I want to fire the JS code from this function

I AM RUNNING the below code in the protected void from xxxx.aspx which is referenced in the Site.Master file... ID="MainContent"

        protected void gvTrappers_SelectedIndexChanged(object sender, EventArgs e)
        {
            int i;
            if (row != null)
            {
                i = row.RowIndex; ;
            }
            else
            {
                btnExpandCritters_Click(sender, e); // pass it on....
            }

            // =====================================

            string IDGUID = Session["NWTL_ID_String"].ToString();
            string IDGUIDstring = IDGUID;    
            string nIDGUID11 = "alert(\"" + IDGUIDstring + "\")";           
            string script = nIDGUID11;

            ScriptManager.RegisterStartupScript(this, GetType(),"ServerControlScript", script, true);

            ScriptManager.RegisterStartupScript(this, GetType(), "Javascript", "javascript: myFunctionCSharp(IDGUID);", true);
        }‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

In the EXTERNAL JS PAGE

require([
    "esri/Map", "esri/views/MapView", "esri/layers/FeatureLayer"
], function (Map, MapView, FeatureLayer
) {
        "use strict";

function myFunctionCSharp(input) {
     var inputValue = input;
     alert(inputValue);
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Tue, 05 May 2020 19:46:18 GMT

Than Aung‌

I saw this...Not sure how to call a function that is in the JS file itself though....

Using JavaScript Along with ASP.NET 2.0 | Microsoft Docs

Keeping JavaScript in a Separate File (.js)

Keeping JavaScript functions in a separate file (a .js file) is highly recommended. Once they are in a separate file and part of a project, the file can be imported into a page using some of the methods already described.

For instance, a .js file can be included in an ASP.NET page using the following code:

Visual Basic

Page.ClientScript.RegisterClientScriptBlock(Me.GetType(), "MyScript", _

"MyJavaScriptFile.js")

Page.ClientScript.RegisterClientScriptBlock(this.GetType(), "MyScript",

"MyJavaScriptFile.js");

Once the .js file is imported into the ASP.NET page, any of the JavaScript functions can be called as before. This is a great way to manage JavaScript functions and keep them separate from the other logic of ASP.NET pages. It is also an easy way to use the same JavaScript functions on multiple ASP.NET pages.

Re: Call JavaScript Function from C# .aspx .net app

Anonymous User — Wed, 06 May 2020 05:42:25 GMT

Hi jay kapalczynski‌,

It seems you got complicated requirement.

For your case of gvTrappers_SelectedIndexChanged server side code, the necessary data from your client side javascript is session["NWTL_ID_String"] value from server side.

I might save hat session value into hiddenfield control into your asp.net form.

And that for selectedindexchanged event, I will just make a call from client side code, and retrieve the hiddenfield value.

Sound good?

I normally trying to avoid calling or injecting js snippet from server side like Page.ClientScript.RegisterClientScriptBlock method.

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Wed, 06 May 2020 12:17:57 GMT

Not exactly....

I can get the session variable and place it in a hidden control no issues

I can retrieve the controls value no issues but thats not my problem

My issue is that I need to call a function in an external JS page from C#, not a page load trigger, not a button trigger, not a dom ready trigger.

After the selectedindexchanged event fires I need to call a JS function in an external JS page and pass that value to a JS function that resides in an external JS page

Below is the only way I know how to run JS code from within C#

BUT I need a way to call a JS function that is NOT in the .cs page

ScriptManager.RegisterStartupScript(this, GetType(), "ServerControlScript2", "alert('TestString');", true);

Can I use the below to call a function in the JS Page itself?

ScriptManager.RegisterStartupScript(this, GetType(), "index", "javascript: myFunction();", true);

Re: Call JavaScript Function from C# .aspx .net app

Anonymous User — Fri, 08 May 2020 04:55:06 GMT

Hi jay kapalczynski‌,

From js page, either aspx or html or js files, you don't need to use ScriptManager if you want to call myFunction() js.

But in aspx file, if you really need that scriptmanager you can use inline script.

And you can even mix with C# function call which is written in cs file or can be written csharp code in aspx.

Below is for your reference.

https://support.microsoft.com/en-au/help/976112/introduction-to-asp-net-inline-expressions-in-the-net-framework

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:09:10 GMT

Hi Than Aung‌ first off thank you for your continued support with this...thinking that I am getting close to an end and will be defeated....while understanding the issues related to server and client side programming....

I totally agree with the url you posted. BUT again this is when the JS is in the HTML page. That is NOT my case

I am referring to the situation when the JS is an external page. I do not see anywhere n the URL link you provided where they call and external JS page....all the JS is in the aspx page

Successful but cannot be used:

1. As stated I can use the ScriptManager and convert all my JS code to an escaped string and run it through there...

2. As stated I can call the external JS code from a Button in xxxx.aspx page

3. As stated I can call the external JS page via page load complete and the dojo ready function in the JS page

But this cannot be used in my case because the way the designer made the aspx page

4. As you stated I can call JS code BUT that code has to be in <script> tags in the xxxx.aspx page

Although I am trying to call a JS function in a seperate JS page from the xxxx.aspx.cs page.

I am assuming that this cannot be done as no solution has presented itself.

Trying to call the JS function from within the xxxx.aspx.cs page ... NO GO

in the xxx.aspx page

<script type="text/javascript" lang="javascript" src="js/index.js">‍‍

in the xxx.aspx.cs page

protected void gvTrappers_SelectedIndexChanged(object sender, EventArgs e)
{
    // CALL EXTERNAL JS FUNCTION that is in js/index.js
    myFunction();  

}‍‍‍‍‍‍‍‍‍‍‍‍

I tried this at the end of the xxxx.aspx page

Trying to load my js page and then call a function in it....NO GO

    <script type="text/javascript" lang="javascript" src="js/index.js">
        myFunction(); 
    </script>‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

jaykapalczynski — Sun, 12 Dec 2021 09:09:13 GMT

Than Aung‌ I cannot thank you enough for all your thoughts and support....I had a difficult case here as I was restrained by the developer that created this website and think that through your thoughts and steering I was able to come up with a solution....OF course this could not have happened without your guidance.....I cannot thank you enough....peace.

I think I may have found a solution that works for me....

My main issue was that I could not rely on the page load complete event to reference my javascript code because of the way the web site was designed. But the dojo/ready was always an option if I could control when I called it....

After some testing I think this is the solution....right now I am simply calling this on the page load complete. which as stated before was an issue....

I should be able to control when this is called....whether it be on a text box focus, combo box change etc...etc

I NOW have absolute control when I load the JS page using the dojo/ready function to start my code.

protected void Page_Load(object sender, EventArgs e)
{
   Page.LoadComplete += new EventHandler(Page_LoadComplete);
}


void Page_LoadComplete(object sender, EventArgs e)
{
    string myScript2 = "\n<script type=\"text/javascript\" language=\"Javascript\" src=\"js/index.js\">\n";
    myScript2 += "\n\n </script>";
    Page.ClientScript.RegisterStartupScript(this.GetType(), "myKey", myScript2, false);
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

I should now be able to do this like I was trying to do !!!!!! Still relaying on when the script loads

protected void gvNew_SelectedIndexChanged(object sender, EventArgs e)
{
   string myScript2 = "\n<script type=\"text/javascript\" language=\"Javascript\" src=\"js/index.js\">\n";
   myScript2 += "\n\n </script>";
   Page.ClientScript.RegisterStartupScript(this.GetType(), "myKey", myScript2, false);
}‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: Call JavaScript Function from C# .aspx .net app

Anonymous User — Tue, 12 May 2020 06:51:22 GMT

No worries jay kapalczynski‌,

That's good idea by registering startupscript .