Calling javascript on blazor server side - javascript

How can i call javascript in a blazor server application? I am trying to follow this document
http://www.binaryintellect.net/articles/aede436b-4c57-4551-a7b4-a005f2aed499.aspx
On my ui.razor file i created the following code
#inject IJSRuntime JsRuntime;
...
private async void callWidgetApplication()
{
var fetched = await JSRuntime.InvokeAsync<bool>("fetchComponenent", DotNetObjectReference.Create(this));
}
I create a file on my wwwroot call Widget.js. this is what i have for the moment
function fetchComponenent() {
return true;
}
But i keep getting an error on my invokeasync.
CS1503 Argument 2: cannot convert from 'Microsoft.JSInterop.DotNetObjectReference<InfoAccessBlz.Pages.InfoAccess>' to 'object?[]?'
The whole reason in using javascript is to call an other website using ajax. So maybe if there is a better way, this is not an api, but its to retrieve an html site.

await JsRuntime.InvokeVoidAsync("fetchComponenent");
Your JavaScript Function doesn't accept any parameter and add the JavaScript file to the _Host.cshtml like this
<script src="~/Widget.js"></script>

Related

Access RESX file from external javascript file [duplicate]

How would one get resx resource strings into javascript code stored in a .js file?
If your javascript is in a script block in the markup, you can use this syntax:
<%$Resources:Resource, FieldName %>
and it will parse the resource value in as it renders the page... Unfortunately, that will only be parsed if the javascript appears in the body of the page. In an external .js file referenced in a <script> tag, those server tags obviously never get parsed.
I don't want to have to write a ScriptService to return those resources or anything like that, since they don't change after the page is rendered so it's a waste to have something that active.
One possibility could be to write an ashx handler and point the <script> tags to that, but I'm still not sure how I would read in the .js files and parse any server tags like that before streaming the text to the client. Is there a line of code I can run that will do that task similarly to the ASP.NET parser?
Or does anyone have any other suggestions?
Here is my solution for now. I am sure I will need to make it more versatile in the future... but so far this is good.
using System.Collections;
using System.Linq;
using System.Resources;
using System.Web.Mvc;
using System.Web.Script.Serialization;
public class ResourcesController : Controller
{
private static readonly JavaScriptSerializer Serializer = new JavaScriptSerializer();
public ActionResult GetResourcesJavaScript(string resxFileName)
{
var resourceDictionary = new ResXResourceReader(Server.MapPath("~/App_GlobalResources/" + resxFileName + ".resx"))
.Cast<DictionaryEntry>()
.ToDictionary(entry => entry.Key.ToString(), entry => entry.Value.ToString());
var json = Serializer.Serialize(resourceDictionary);
var javaScript = string.Format("window.Resources = window.Resources || {{}}; window.Resources.{0} = {1};", resxFileName, json);
return JavaScript(javaScript);
}
}
// In the RegisterRoutes method in Global.asax:
routes.MapRoute("Resources", "resources/{resxFileName}.js", new { controller = "Resources", action = "GetResourcesJavaScript" });
So I can do
<script src="/resources/Foo.js"></script>
and then my scripts can reference e.g. window.Resources.Foo.Bar and get a string.
There's no native support for this.
I built a JavaScriptResourceHandler a while ago that can serve Serverside resources into the client page via objects where each property on the object represents a localization resource id and its value. You can check this out and download it from this blog post:
http://www.west-wind.com/Weblog/posts/698097.aspx
I've been using this extensively in a number of apps and it works well. The main win on this is that you can localize your resources in one place (Resx or in my case a custom ResourceProvider using a database) rather than having to have multiple localization schemes.
whereas "Common" is the name of the resource file and Msg1 is the fieldname. This also works for culture changes.
Partial Javascript...:
messages:
{
<%=txtRequiredField.UniqueID %>:{
required: "<%=Resources.Common.Msg1 %>",
maxlength: "Only 50 character allowed in required field."
}
}
In a nutshell, make ASP.NET serve javascript rather than HTML for a specific page. Cleanest if done as a custom IHttpHandler, but in a pinch a page will do, just remember to:
1) Clear out all the ASP.NET stuff and make it look like a JS file.
2) Set the content-type to "text/javascript" in the codebehind.
Once you have a script like this setup, you can then create a client-side copy of your resources that other client-side scripts can reference from your app.
If you have your resources in a separate assembly you can use the ResourceSet instead of the filename. Building on #Domenics great answer:
public class ResourcesController : Controller
{
private static readonly JavaScriptSerializer Serializer = new JavaScriptSerializer();
public ActionResult GetResourcesJavaScript()
{
// This avoids the file path dependency.
ResourceSet resourceSet = MyResource.ResourceManager.GetResourceSet(CultureInfo.CurrentUICulture, true, true);
// Create dictionary.
var resourceDictionary = resourceSet
.Cast<DictionaryEntry>()
.ToDictionary(entry => entry.Key.ToString(), entry => entry.Value.ToString());
var json = Serializer.Serialize(resourceDictionary);
var javaScript = string.Format("window.Resources = window.Resources || {{}}; window.Resources.resources = {1};", json);
return JavaScript(javaScript);
}
}
The downside is that this will not enable more than one resource-file per action. In that way #Domenics answer is more generic and reusable.
You may also consider using OutputCache, since the resource won't change a lot between requests.
[OutputCache(Duration = 3600, Location = OutputCacheLocation.ServerAndClient)]
public ActionResult GetResourcesJavaScript()
{
// Logic here...
}
http://www.asp.net/mvc/overview/older-versions-1/controllers-and-routing/improving-performance-with-output-caching-cs
I usually pass the resource string as a parameter to whatever javascript function I'm calling, that way I can continue to use the expression syntax in the HTML.
I the brown field application I'm working on we have an xslt that transforms the resx file into a javascript file as part of the build process. This works well since this is a web application. I'm not sure if the original question is a web application.
use a hidden field to hold the resource string value and then access the field value in javascript
for example :
" />
var todayString= $("input[name=TodayString][type=hidden]").val();
Add the function in the BasePage class:
protected string GetLanguageText(string _key)
{
System.Resources.ResourceManager _resourceTemp = new System.Resources.ResourceManager("Resources.Language", System.Reflection.Assembly.Load("App_GlobalResources"));
return _resourceTemp.GetString(_key);
}
Javascript:
var _resurceValue = "<%=GetLanguageText("UserName")%>";
or direct use:
var _resurceValue = "<%= Resources.Language.UserName %>";
Note:
The Language is my resouce name. Exam: Language.resx and Language.en-US.resx

How to call javascript function in a JS file to a controller using ASP.Net MVC?

I'm having a problem trying to call a javascript function in a JS file to a controller. I wanted to use the function in the JS file then return the value to a controller who calls that function.
Here is my code:
(JS File)
function getQueryString(url) {
var arrSplit = url.split('?');
return arrSplit.length > 1 ? url.substring(url.indexOf('?')+1) : '';
}
And I wanted to make a call like this in my controller.
(Controller)
private string DoSomething(){
getQueryString("http://sample.com");
}
Is is this possible? Or if ever do you have any suggestions or any possible workarounds?
First of all, MVC does not work that way. You cannot refer JS methods from your MVC controller. MVC controlled executes on the backend and just formulates your View. Once your HTML view is returned to the client, it executes there, And you JS is on the client-side. If you need to call a method in your JS on the browser side, from a server-side Controller, you need to use SignalR.

How to call C# class method using Javascript?

I have created Class under App_Code folder there i have created method.
I need to call that class method using JavaScript from Sample.aspx file.
Class:
namespace ContactBook.App_Code
{
//The function need to call...
public class ContactBook_functionalities
{
public static bool MyFunction(string email, string contact)
{
//Code...
}
}
}
JavaScript:
<script type="text/javascript">
function callMyFunc(email, contact)
{
//var x = MyFunction(string email, string contact);
}
</script>
[WebMethod] is not working for Class functions.
I don't thing you can do that because:
ASPX is server side, whereas JavaScript is client side
some components from a ASP site are compiled
What you can do is expose a route (if you were using MVC desing pattern) on the server that calls that function (or an Api for that mather).
You need to expose an HTTP handler in ASP.net or Controllers / Web API in MVC for your JavaScript to have the capability of talking to the server. Simple classes are not accessible outside ASP.net Application via JavaScript.
After creating your own controller/HTTP handler, you need to send an AJAX request to the controller and it should look like this code below:
$.ajax({
url: "sampleurlhere",
type: "POST"//POST or GET,
data: {
id: "sample id as parameter"
},
success: function(e) {
//this event fires up when response arrives.
}
})

how to Call a specific method of my Web Service from java script?

i am trying to call a web service from my pure HTML page using java script.
i had successfully created a web service using java on net beans. now i want to call a method from that web service using java script with sending some parameters to the web Service, i had tried so far but not succeed yet.
i had successfully called the method using jsp page, but i need to do it by using simple html page.
i had seen an example Here but it is not working with me. :(
can you please give me some example, so that i come to know how to call a specific method of my web service from java script with sending some parameters to the web service.
thanks in advance.
EDIT
my script
function validateForm(frm)
{
document.forms[0].action="http://localhost:8084/Web_Service_Example/CircleFunctions?"
document.forms[0].method="post"
document.forms[0].submit()
}
my CircleFunctions method
public class CircleFunctions {
public int sum()
{
int a = 20;
int b = 40;
int c = a+b;
return c;
}
}
document.forms[0].action="http://localhost:8080/webservice/services/add"
document.forms[0].method="get"
document.forms[0].submit()

Call ASP.NET function from JavaScript?

I'm writing a web page in ASP.NET. I have some JavaScript code, and I have a submit button with a click event.
Is it possible to call a method I created in ASP with JavaScript's click event?
Well, if you don't want to do it using Ajax or any other way and just want a normal ASP.NET postback to happen, here is how you do it (without using any other libraries):
It is a little tricky though... :)
i. In your code file (assuming you are using C# and .NET 2.0 or later) add the following Interface to your Page class to make it look like
public partial class Default : System.Web.UI.Page, IPostBackEventHandler{}
ii. This should add (using Tab-Tab) this function to your code file:
public void RaisePostBackEvent(string eventArgument) { }
iii. In your onclick event in JavaScript, write the following code:
var pageId = '<%= Page.ClientID %>';
__doPostBack(pageId, argumentString);
This will call the 'RaisePostBackEvent' method in your code file with the 'eventArgument' as the 'argumentString' you passed from the JavaScript. Now, you can call any other event you like.
P.S: That is 'underscore-underscore-doPostBack' ... And, there should be no space in that sequence... Somehow the WMD does not allow me to write to underscores followed by a character!
The __doPostBack() method works well.
Another solution (very hackish) is to simply add an invisible ASP button in your markup and click it with a JavaScript method.
<div style="display: none;">
<asp:Button runat="server" ... OnClick="ButtonClickHandlerMethod" />
</div>
From your JavaScript, retrieve the reference to the button using its ClientID and then call the .click() method on it.
var button = document.getElementById(/* button client id */);
button.click();
The Microsoft AJAX library will accomplish this. You could also create your own solution that involves using AJAX to call your own aspx (as basically) script files to run .NET functions.
I suggest the Microsoft AJAX library. Once installed and referenced, you just add a line in your page load or init:
Ajax.Utility.RegisterTypeForAjax(GetType(YOURPAGECLASSNAME))
Then you can do things like:
<Ajax.AjaxMethod()> _
Public Function Get5() AS Integer
Return 5
End Function
Then, you can call it on your page as:
PageClassName.Get5(javascriptCallbackFunction);
The last parameter of your function call must be the javascript callback function that will be executed when the AJAX request is returned.
You can do it asynchronously using .NET Ajax PageMethods. See here or here.
I think blog post How to fetch & show SQL Server database data in ASP.NET page using Ajax (jQuery) will help you.
JavaScript Code
<script src="http://code.jquery.com/jquery-3.3.1.js" />
<script language="javascript" type="text/javascript">
function GetCompanies() {
$("#UpdatePanel").html("<div style='text-align:center; background-color:yellow; border:1px solid red; padding:3px; width:200px'>Please Wait...</div>");
$.ajax({
type: "POST",
url: "Default.aspx/GetCompanies",
data: "{}",
dataType: "json",
contentType: "application/json; charset=utf-8",
success: OnSuccess,
error: OnError
});
}
function OnSuccess(data) {
var TableContent = "<table border='0'>" +
"<tr>" +
"<td>Rank</td>" +
"<td>Company Name</td>" +
"<td>Revenue</td>" +
"<td>Industry</td>" +
"</tr>";
for (var i = 0; i < data.d.length; i++) {
TableContent += "<tr>" +
"<td>"+ data.d[i].Rank +"</td>" +
"<td>"+data.d[i].CompanyName+"</td>" +
"<td>"+data.d[i].Revenue+"</td>" +
"<td>"+data.d[i].Industry+"</td>" +
"</tr>";
}
TableContent += "</table>";
$("#UpdatePanel").html(TableContent);
}
function OnError(data) {
}
</script>
ASP.NET Server Side Function
[WebMethod]
[ScriptMethod(ResponseFormat= ResponseFormat.Json)]
public static List<TopCompany> GetCompanies()
{
System.Threading.Thread.Sleep(5000);
List<TopCompany> allCompany = new List<TopCompany>();
using (MyDatabaseEntities dc = new MyDatabaseEntities())
{
allCompany = dc.TopCompanies.ToList();
}
return allCompany;
}
Static, strongly-typed programming has always felt very natural to me, so at first I resisted learning JavaScript (not to mention HTML and CSS) when I had to build web-based front-ends for my applications. I would do anything to work around this like redirecting to a page just to perform and action on the OnLoad event, as long as I could code pure C#.
You will find however that if you are going to be working with websites, you must have an open mind and start thinking more web-oriented (that is, don't try to do client-side things on the server and vice-versa). I love ASP.NET webforms and still use it (as well as MVC), but I will say that by trying to make things simpler and hiding the separation of client and server it can confuse newcomers and actually end up making things more difficult at times.
My advice is to learn some basic JavaScript (how to register events, retrieve DOM objects, manipulate CSS, etc.) and you will find web programming much more enjoyable (not to mention easier). A lot of people mentioned different Ajax libraries, but I didn't see any actual Ajax examples, so here it goes. (If you are not familiar with Ajax, all it is, is making an asynchronous HTTP request to refresh content (or perhaps perform a server-side action in your scenario) without reloading the entire page or doing a full postback.
Client-Side:
<script type="text/javascript">
var xmlhttp = new XMLHttpRequest(); // Create object that will make the request
xmlhttp.open("GET", "http://example.org/api/service", "true"); // configure object (method, URL, async)
xmlhttp.send(); // Send request
xmlhttp.onstatereadychange = function() { // Register a function to run when the state changes, if the request has finished and the stats code is 200 (OK). Write result to <p>
if (xmlhttp.readyState == 4 && xmlhttp.statsCode == 200) {
document.getElementById("resultText").innerHTML = xmlhttp.responseText;
}
};
</script>
That's it. Although the name can be misleading the result can be in plain text or JSON as well, you are not limited to XML. jQuery provides an even simpler interface for making Ajax calls (among simplifying other JavaScript tasks).
The request can be an HTTP-POST or HTTP-GET and does not have to be to a webpage, but you can post to any service that listens for HTTP requests such as a RESTful API. The ASP.NET MVC 4 Web API makes setting up the server-side web service to handle the request a breeze as well. But many people do not know that you can also add API controllers to web forms project and use them to handle Ajax calls like this.
Server-Side:
public class DataController : ApiController
{
public HttpResponseMessage<string[]> Get()
{
HttpResponseMessage<string[]> response = new HttpResponseMessage<string[]>(
Repository.Get(true),
new MediaTypeHeaderValue("application/json")
);
return response;
}
}
Global.asax
Then just register the HTTP route in your Global.asax file, so ASP.NET will know how to direct the request.
void Application_Start(object sender, EventArgs e)
{
RouteTable.Routes.MapHttpRoute("Service", "api/{controller}/{id}");
}
With AJAX and Controllers, you can post back to the server at any time asynchronously to perform any server side operation. This one-two punch provides both the flexibility of JavaScript and the power the C# / ASP.NET, giving the people visiting your site a better overall experience. Without sacrificing anything, you get the best of both worlds.
References
Ajax,
jQuery Ajax,
Controller in Webforms
The Microsoft AJAX library will accomplish this. You could also create your own solution that involves using AJAX to call your own aspx (as basically) script files to run .NET functions.
This is the library called AjaxPro which was written an MVP named Michael Schwarz. This was library was not written by Microsoft.
I have used AjaxPro extensively, and it is a very nice library, that I would recommend for simple callbacks to the server. It does function well with the Microsoft version of Ajax with no issues. However, I would note, with how easy Microsoft has made Ajax, I would only use it if really necessary. It takes a lot of JavaScript to do some really complicated functionality that you get from Microsoft by just dropping it into an update panel.
It is so easy for both scenarios (that is, synchronous/asynchronous) if you want to trigger a server-side event handler, for example, Button's click event.
For triggering an event handler of a control:
If you added a ScriptManager on your page already then skip step 1.
Add the following in your page client script section
//<![CDATA[
var theForm = document.forms['form1'];
if (!theForm) {
theForm = document.form1;
}
function __doPostBack(eventTarget, eventArgument) {
if (!theForm.onsubmit || (theForm.onsubmit() != false)) {
theForm.__EVENTTARGET.value = eventTarget;
theForm.__EVENTARGUMENT.value = eventArgument;
theForm.submit();
}
}
//]]>
Write you server side event handler for your control
protected void btnSayHello_Click(object sender, EventArgs e)
{
Label1.Text = "Hello World...";
}
Add a client function to call the server side event handler
function SayHello() {
__doPostBack("btnSayHello", "");
}
Replace the "btnSayHello" in code above with your control's client id.
By doing so, if your control is inside an update panel, the page will not refresh. That is so easy.
One other thing to say is that: Be careful with client id, because it depends on you ID-generation policy defined with the ClientIDMode property.
I'm trying to implement this but it's not working right. The page is
posting back, but my code isn't getting executed. When i debug the
page, the RaisePostBackEvent never gets fired. One thing i did
differently is I'm doing this in a user control instead of an aspx
page.
If anyone else is like Merk, and having trouble over coming this, I have a solution:
When you have a user control, it seems you must also create the PostBackEventHandler in the parent page. And then you can invoke the user control's PostBackEventHandler by calling it directly. See below:
public void RaisePostBackEvent(string _arg)
{
UserControlID.RaisePostBackEvent(_arg);
}
Where UserControlID is the ID you gave the user control on the parent page when you nested it in the mark up.
Note: You can also simply just call methods belonging to that user control directly (in which case, you would only need the RaisePostBackEvent handler in the parent page):
public void RaisePostBackEvent(string _arg)
{
UserControlID.method1();
UserControlID.method2();
}
You might want to create a web service for your common methods.
Just add a WebMethodAttribute over the functions you want to call, and that's about it.
Having a web service with all your common stuff also makes the system easier to maintain.
If the __doPostBack function is not generated on the page you need to insert a control to force it like this:
<asp:Button ID="btnJavascript" runat="server" UseSubmitBehavior="false" />
Regarding:
var button = document.getElementById(/* Button client id */);
button.click();
It should be like:
var button = document.getElementById('<%=formID.ClientID%>');
Where formID is the ASP.NET control ID in the .aspx file.
Add this line to page load if you are getting object expected error.
ClientScript.GetPostBackEventReference(this, "");
You can use PageMethods.Your C# method Name in order to access C# methods or VB.NET methods into JavaScript.
Try this:
if(!ClientScript.IsStartupScriptRegistered("window"))
{
Page.ClientScript.RegisterStartupScript(this.GetType(), "window", "pop();", true);
}
Or this
Response.Write("<script>alert('Hello World');</script>");
Use the OnClientClick property of the button to call JavaScript functions...
You can also get it by just adding this line in your JavaScript code:
document.getElementById('<%=btnName.ClientID%>').click()
I think this one is very much easy!
Please try this:
<%= Page.ClientScript.GetPostBackEventReference(ddlVoucherType, String.Empty) %>;
ddlVoucherType is a control which the selected index change will call... And you can put any function on the selected index change of this control.
The simplest and best way to achieve this is to use the onmouseup() JavaScript event rather than onclick()
That way you will fire JavaScript after you click and it won't interfere with the ASP OnClick() event.
I try this and so I could run an Asp.Net method while using jQuery.
Do a page redirect in your jQuery code
window.location = "Page.aspx?key=1";
Then use a Query String in Page Load
protected void Page_Load(object sender, EventArgs e)
{
if (Request.QueryString["key"] != null)
{
string key= Request.QueryString["key"];
if (key=="1")
{
// Some code
}
}
}
So no need to run an extra code
This reply works like a breeze for me thanks cross browser:
The __doPostBack() method works well.
Another solution (very hackish) is to simply add an invisible ASP button in your markup and click it with a JavaScript method.
<div style="display: none;">
<asp:Button runat="server" ... OnClick="ButtonClickHandlerMethod" />
</div>
From your JavaScript, retrieve the reference to the button using its ClientID and then call the .Click() method on it:
var button = document.getElementByID(/* button client id */);
button.Click();
Blockquote

Categories

Resources