Develop Reference

Transforming void function in webmethod

I have a Function that populates a list box(DiveSiteList) when the page is loaded, and that is working just fine.
namespace DiveApp_WebApplication
{
public partial class HomePage : System.Web.UI.Page
{
private static DiveManager.DiveManager Manager;
protected void Page_Load(object sender, EventArgs e)
{
Manager = new DiveManager.DiveManager();
BindDiveList();
}
private void BindDiveList()
{
foreach (DiveSite DS in Manager.MasterDiveSiteList)
{
ListItem Item = new ListItem();
Item.Text = DS.DiveSiteName;
Item.Attributes.Add("Name", DS.DiveSiteName);
Item.Attributes.Add("Latitude", DS.Latitude.ToString().Replace(",", "."));
Item.Attributes.Add("Longitude", DS.Longitude.ToString().Replace(",","."));
Item.Attributes.Add("ID", DS.DiveSiteID.ToString());
Item.Attributes.Add("Vis", DS.AvarageVisibility.ToString());
Item.Attributes.Add("Depth", DS.MaximumDepth.ToString());
DiveSiteList.Items.Add(Item);
}
}
But now I need nuke and repopulate that list from JavaScript, and I'm not sure how.
I tried this, but it says that "an object reference is required for the nonstatic field method or property" on the DiveSiteList(the list box in the web page):
[System.Web.Services.WebMethod()]
private static int BindDiveListWeb()
{
DiveSiteList.Items.Clear();
foreach (DiveSite DS in Manager.MasterDiveSiteList)
{
ListItem Item = new ListItem();
Item.Text = DS.DiveSiteName;
Item.Attributes.Add("Name", DS.DiveSiteName);
Item.Attributes.Add("Latitude", DS.Latitude.ToString().Replace(",", "."));
Item.Attributes.Add("Longitude", DS.Longitude.ToString().Replace(",", "."));
Item.Attributes.Add("ID", DS.DiveSiteID.ToString());
Item.Attributes.Add("Vis", DS.AvarageVisibility.ToString());
Item.Attributes.Add("Depth", DS.MaximumDepth.ToString());
DiveSiteList.Items.Add(Item);
}
return 1;
}
I tried a few different things but I'm a bit lost, can anyone help?
Edit: MasterDiveSiteList
public List<DiveSite> MasterDiveSiteList;
DiveDBClass = new DBAccessClass();
Initialize();
private void Initialize()
{
MasterDiveSiteList = DiveDBClass.GetAllDiveSites();
}

When you populate the list the first time, the instance exists because it executes within the context of the page.
When you call the method via JavaScript however, you are using a static instance which does not have the context you had before when loading the page.
The correct way to do this is to have the JavaScript method receive the list of items. You can then populate them on the client side.
Check this out:
How to fill a DropDown using Jquery Ajax Call?

c# web browser Invoke Script in event handler not working [duplicate]

Why I'm getting this error?
System.InvalidCastException was unhandled by user code
Message=Specified cast is not valid.
Source=System.Windows.Forms
StackTrace:
at System.Windows.Forms.UnsafeNativeMethods.IHTMLDocument2.GetLocation()
at System.Windows.Forms.WebBrowser.get_Document()
at System.Windows.Forms.WebBrowser.get_DocumentStream()
at System.Windows.Forms.WebBrowser.get_DocumentText()
at SiteBot.MainWindow.backgroundWorker1_DoWork(Object sender, DoWorkEventArgs e) in D:\Documents\Visual Studio 2010\Projects\SiteBot\MainWindow.cs:line 35
at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)
InnerException:

The following solves your cross thread issue.
public delegate string GetStringHandler();
public string GetDocumentText()
{
if (InvokeRequired)
return Invoke(new GetStringHandler(GetDocumentText)) as string;
else
return webBrowser.DocumentText;
}
if (regAddId.IsMatch(GetDocumentText()))
{
}

I get a threading exception with this test:
public class Test
{
private readonly WebBrowser wb;
public Test()
{
wb = new WebBrowser();
var bw = new BackgroundWorker();
bw.DoWork += DoWork;
bw.RunWorkerAsync();
while (bw.IsBusy)
{
Thread.Sleep(10);
Application.DoEvents();
}
}
private void DoWork(object sender, DoWorkEventArgs e)
{
wb.Navigate(#"www.clix-cents.com/pages/clickads");
Thread.Sleep(1000);
var regex = new Regex("onclick=\\'openad\\(\"([\\d\\w]+\"\\);");
regex.IsMatch(wb.DocumentText);
}
}
public class Program
{
[STAThread]
public static void Main(string[] args)
{
new Test();
}
}
The exception looks like this:
Since WebBrowser is really just a wrapper around IE's ActiveX control, you'll need to be careful about threading issues. I think what you really want to use here is a WebClient and not a WebBrowser, but I'm just guessing about your application.
[EDIT]
Like #Fun states you can just Invoke over to the GUI thread (assuming thats where the control was created. I'd still recommend using a WebClient.

How do i receive messages periodically from Signalr to all Clients automatically ,without client input?

I am new to SignalR. I need to send message from SignalR to all connected clients automatically with some delay without client input ?
The above process has to be repeated, while recursively?
Is it possible?
Without client input, the SignalR can send messages automatically to clients repeatedly?
This is my JavaScript cleint code:
$(function () {
var chat = $.connection.timehub;
$.connection.hub.start();
chat.client.broadcastMessage = function (current) {
var now = current;
console.log(current);
$('div.container').append('<p><strong>' + now + '</strong></p>');
}
};
and this is my Timehub
public class timehub : Hub
{
public void Send(string current)
{
current = DateTime.Now.ToString("HH:mm:ss:tt");
Clients.All.broadcastMessage(current);
System.Threading.Thread.Sleep(5000);
Send(current);
}
}
and this is my Owin Startup Class:
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR();
}
}
Could anyone provide me an solution for this?

If you will keep calling the Send() method recursively like you do right now, you will get a stackoverflow exception. Just wrap the code inside the method in a while(true) loop:
public class timehub : Hub
{
public void Send()
{
while(true)
{
var current = DateTime.Now.ToString("HH:mm:ss:tt");
Clients.All.broadcastMessage(current);
System.Threading.Thread.Sleep(5000);
}
}
}
I would suggest moving the Send() method to another thread, because the current thread will get stuck forever in this while loop.

infinite scroll in android webview

i have some local html file and i want to show them with infinite scroll method.
NOTE: i cant change the html content, so please don't advice to add javascript to them. i must do it in run time.
so, i figured out that i can execute javascript in runtime via loadUrl("javascript: ....").
i overrided onOverScrolled() method of webView to find out when user reach the end of webView. (it acting carefully, so the problem is not here)
the problem is some times new content attached successfully and other times it didn't geting attached.
in the log i can see that the end of page method get triggered, retrieving new html body get called, executing javascript code get called, but it did not affect.
here is my code, may be something went wrong and i can not see it:
#Override
protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY)
{
super.onOverScrolled(scrollX, scrollY, clampedX, clampedY);
if(clampedY & reloadFlag) //for first time realodFlag is false, when the WebViewClient.onPageFinished() get called it turn to ture
{
if (!(isVerticalScrollPossible(SCROLL_DOWN)))
{
reloadFlag = false;
currUri = nextResource(currUri); //findout next page
appendNextPage();
}
}
}
private final int SCROLL_DOWN = 1;
private final int SCROLL_UP = -1;
private boolean isVerticalScrollPossible(int direction)
{
final int offset = computeVerticalScrollOffset();
final int range = computeVerticalScrollRange() - computeVerticalScrollExtent();
if (range == 0) return false;
if (direction < 0) {
return offset > 0;
} else {
return offset < range - 1;
}
}
public String getNextPageJS(Uri currPage)
{
String body = getNextPageBody(currPage);
//Log.d("myTAG", body);
String jsResult = "javascript:(function() { document.body.innerHTML += '<div id=\"separator\" style=\"height:10px; margin-top:10px; margin-bottom:10px; background-color:#000000;\"></div>" + body + "';})()";
return jsResult;
}
private void appendNextPage()
{
reloadFlag = false;
Thread appendThread = new Thread(null, doAppend, "backgroundAppend");
appendThread.start();
Log.i("appendNextPage", "get called");
}
public String rs = "";
private Runnable doAppend = new Runnable()
{
#Override
public void run()
{
Log.i("doAppend", "get called + currUri: " + currUri);
rs = getNextPageJS(currUri);
//loadUrl(rs);
appendHandler.sendEmptyMessage(0);
}
};
private Handler appendHandler = new Handler()
{
public void handleMessage(Message msg)
{
loadUrl(rs);
reloadFlag = true;
Log.i("appendHandler", "get called");
}
};
NOTE: sometimes i get this in the emulator log (not in real device):
I/chromium(1339): [INFO:CONSOLE(1)] "Uncaught SyntaxError: An invalid or illegal string was specified.", source: http://localhost:1025/OEBPS/Text/Section0042.xhtml (1)
the number of page is different from time to time, may be it's for bad javasccript code, i don't know.
hints:
1) i'm not javascript coder, so may be the javascript code is not good
2) or maybe calling javascript code several times cause this problem
3) i know that javascript code must execute after page loading completely, so maybe the code called too soon, the problem for this is that onPageFinished() getting called just for first page and it does not called when new content attached via javascript code, i tried to solve this problem using thread, and i think it worked.
UPDATE: i figured out that this code works fine when the html body is small, but when i try to attach large body it didn't work. is loadUrl() method has char limit? or any other idea?

OK, i found the problem, if anyone wants to know.
the problem is that the loadUri() (at least in my case) can not load too many html tag at once (in javascript code i written)
so, the solution is easy, load tags one by one.
here is the code i used:
public ArrayList<String> getNextPageBody(Uri currAddress)
{
String html = getHtml(currAddress); // this is the all html tags in the next file
//get body elements as arrayList, using jsoup
Document doc = Jsoup.parse(html);
Elements elements = doc.select("body").first().children();
ArrayList<String> chuncks = new ArrayList<String>();
for (org.jsoup.nodes.Element el : elements)
{
chuncks.add(el.toString());
}
return chuncks;
}
public void loadBodyChunk(ArrayList<String> bodyChunks)
{
//show a separator for each page
bodyChunks.add(0, "javascript:(function() { document.body.innerHTML += '<div id=\"separator\" style=\"height:10px; margin-top:10px; margin-bottom:10px; background-color:#000000;\"></div>';}())");
loadUrl(bodyChunks.get(0));
for(int i = 1; i < bodyChunks.size(); i++)
{
String jsResult = "javascript:(function() { document.body.innerHTML += '" + bodyChunks.get(i) + "';}())";
loadUrl(jsResult);
}
reloadFlag = true;
}
EDIT:
also:
first the 's in String should be replaced with \' :
body = body.replace("'", "\\'");
then all newline char should be eliminated:
body = body.replaceAll(System.getProperty("line.separator"), " ");
all problem solved.

Suppress proxy generation for some hubs or methods

I'm starting out with SignalR and I have a situation where I'm going to have a SignalR site that will be broadcasting messages to clients, but I also need an admin interface that will actually trigger those messages. The admin page will call server side methods that will, in turn, call client side Javascript methods for regular users. So I'm thinking I can either set up two separate hubs (one for admin, one for everybody else) or I can have methods in a single hub that can only be called by the admin that will check authorization.
But in addition to the authorization, I'd like to have SignalR not include admin methods or an admin hub in the generated Javascript proxy classes so that I'm not advertising their existence (again - this is NOT the only security, I will be checking authorization). Is there an attribute or property I can set on individual hubs or on methods within a hub that will suppress them from being included in the proxy (but still have them callable from Javascript)? I know you can set EnableJavaScriptProxies to false in your HubConfiguration, but that seems to be global and I'd like to keep the proxy for the stuff I do want the regular client to be using.

There is one trick using interfaces. As proxy will generate only public methods in proxy, you can create hub using interface like this:
public class MyHub : Hub, IMyHub
{
void IMyHub.NotGeneratedOnClient()
{
}
public void GeneratedOnClient()
{
}
}
NotGeneratedOnClient method will not be visible if you use object of type MyHub, you can access it only using interface. As method is not public proxy generator is not going to add it to client proxy

We don't have a way of excluding specific methods from the proxy today. You'd have to re-implement your own proxy generator that basically does what we do in our default impl but has knowledge of some attribute to skip generation of specific methods.
We can conceivable add this in a future version of SignalR. File an issue on github if you feel strongly about having this.
Here's the default implementation (it would have been easier if we made more methods virtual and non static).
https://github.com/SignalR/SignalR/blob/master/src/Microsoft.AspNet.SignalR.Core/Hubs/DefaultJavaScriptProxyGenerator.cs

Here is a modified DefaultJavaScriptProxyGenerator with the following changes:
It will exclude functions from Javascript proxy generation with a new [HubMethodExcludeFromProxy] attribute.
The private static functions have changed to protected virtual for future derivatives.
The GenerateProxy( ) function has an overload to include DocComments, but that was not caching the results like the non DocComments version. Now they both cache.
Two resources, Resources.DynamicComment_CallsMethodOnServerSideDeferredPromise and Resources.DynamicComment_ServerSideTypeIs were private to another assembly, so to get things to compile, I copied the text from the resource file directly. These two resources are only used if DocComments is true.
All of the DefaultJavaScriptProxyGenerator references were changed to CustomJavaScriptProxyGenerator except for one, which is used to locate the resource script Microsoft.AspNet.SignalR.Scripts.hubs.js, located in a different assembly.
First, you will need to update the dependency resolver to use the new CustomJavaScriptProxyGenerator for the IJavaScriptProxyGenerator interface. If you are using the default resolver, you can set up a custom resolver like this:
map.RunSignalR(
new HubConfiguration() {
Resolver = new CustomDependencyResolver()
}
);
And here is a custom resolver that derives from the DefaultDependecyResolver:
namespace Microsoft.AspNet.SignalR
{
public class CustomDependencyResolver : DefaultDependencyResolver
{
MyDependencyResolver() : base()
{
var proxyGenerator = new Lazy(() => new CustomJavaScriptProxyGenerator(this));
Register(typeof(IJavaScriptProxyGenerator), () => proxyGenerator.Value);
}
}
}
And finally, here is the new CustomJavaScriptProxyGenerator.cs file (the HubMethodExcludeFromProxyAttribute class is at the bottom):
// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
// Mods by Brain2000
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Text;
using Microsoft.AspNet.SignalR.Json;
using Microsoft.AspNet.SignalR.Hubs;
using Newtonsoft.Json;
namespace Microsoft.AspNet.SignalR.Hubs
{
public class CustomJavaScriptProxyGenerator : IJavaScriptProxyGenerator
{
protected static readonly Lazy _templateFromResource = new Lazy(GetTemplateFromResource);
protected static readonly Type[] _numberTypes = new[] { typeof(byte), typeof(short), typeof(int), typeof(long), typeof(float), typeof(decimal), typeof(double) };
protected static readonly Type[] _dateTypes = new[] { typeof(DateTime), typeof(DateTimeOffset) };
protected const string ScriptResource = "Microsoft.AspNet.SignalR.Scripts.hubs.js";
protected readonly IHubManager _manager;
protected readonly IJavaScriptMinifier _javaScriptMinifier;
protected readonly Lazy _generatedTemplate;
protected readonly Lazy _generatedTemplateWithComments;
public CustomJavaScriptProxyGenerator(IDependencyResolver resolver) :
this(resolver.Resolve(),
resolver.Resolve())
{
}
public CustomJavaScriptProxyGenerator(IHubManager manager, IJavaScriptMinifier javaScriptMinifier)
{
_manager = manager;
_javaScriptMinifier = javaScriptMinifier ?? NullJavaScriptMinifier.Instance;
_generatedTemplate = new Lazy(() => GenerateProxy(_manager, _javaScriptMinifier, includeDocComments: false));
_generatedTemplateWithComments = new Lazy(() => GenerateProxy(_manager, _javaScriptMinifier, includeDocComments: true));
}
public string GenerateProxy(string serviceUrl)
{
serviceUrl = JavaScriptEncode(serviceUrl);
return _generatedTemplate.Value.Replace("{serviceUrl}", serviceUrl);
}
public string GenerateProxy(string serviceUrl, bool includeDocComments)
{
if (!includeDocComments) return GenerateProxy(serviceUrl); //use the includeDocComments: false cached version
serviceUrl = JavaScriptEncode(serviceUrl);
return _generatedTemplateWithComments.Value.Replace("{serviceUrl}", serviceUrl);
}
protected virtual string GenerateProxy(IHubManager hubManager, IJavaScriptMinifier javaScriptMinifier, bool includeDocComments)
{
string script = _templateFromResource.Value;
var hubs = new StringBuilder();
var first = true;
foreach (var descriptor in hubManager.GetHubs().OrderBy(h => h.Name))
{
if (!first)
{
hubs.AppendLine(";");
hubs.AppendLine();
hubs.Append(" ");
}
GenerateType(hubManager, hubs, descriptor, includeDocComments);
first = false;
}
if (hubs.Length > 0)
{
hubs.Append(";");
}
script = script.Replace("/*hubs*/", hubs.ToString());
return javaScriptMinifier.Minify(script);
}
protected virtual void GenerateType(IHubManager hubManager, StringBuilder sb, HubDescriptor descriptor, bool includeDocComments)
{
// Get only actions with minimum number of parameters.
var methods = GetMethods(hubManager, descriptor);
var hubName = GetDescriptorName(descriptor);
sb.AppendFormat(" proxies['{0}'] = this.createHubProxy('{1}'); ", hubName, hubName).AppendLine();
sb.AppendFormat(" proxies['{0}'].client = {{ }};", hubName).AppendLine();
sb.AppendFormat(" proxies['{0}'].server = {{", hubName);
bool first = true;
foreach (var method in methods)
{
if (!first)
{
sb.Append(",").AppendLine();
}
GenerateMethod(sb, method, includeDocComments, hubName);
first = false;
}
sb.AppendLine();
sb.Append(" }");
}
protected virtual string GetDescriptorName(Descriptor descriptor)
{
if (descriptor == null)
{
throw new ArgumentNullException("descriptor");
}
string name = descriptor.Name;
// If the name was not specified then do not camel case
if (!descriptor.NameSpecified)
{
name = JsonUtility.CamelCase(name);
}
return name;
}
protected virtual IEnumerable GetMethods(IHubManager manager, HubDescriptor descriptor)
{
return from method in manager.GetHubMethods(descriptor.Name).Where(md => md.Attributes.FirstOrDefault(a => (a.GetType() == typeof(HubMethodExcludeFromProxyAttribute))) == null)
group method by method.Name into overloads
let oload = (from overload in overloads
orderby overload.Parameters.Count
select overload).FirstOrDefault()
orderby oload.Name
select oload;
}
protected virtual void GenerateMethod(StringBuilder sb, MethodDescriptor method, bool includeDocComments, string hubName)
{
var parameterNames = method.Parameters.Select(p => p.Name).ToList();
sb.AppendLine();
sb.AppendFormat(" {0}: function ({1}) {{", GetDescriptorName(method), Commas(parameterNames)).AppendLine();
if (includeDocComments)
{
sb.AppendFormat(" /// Calls the {0} method on the server-side {1} hub.\nReturns a jQuery.Deferred() promise.", method.Name, method.Hub.Name).AppendLine();
var parameterDoc = method.Parameters.Select(p => String.Format(CultureInfo.CurrentCulture, " /// Server side type is {2}", p.Name, MapToJavaScriptType(p.ParameterType), p.ParameterType)).ToList();
if (parameterDoc.Any())
{
sb.AppendLine(String.Join(Environment.NewLine, parameterDoc));
}
}
sb.AppendFormat(" return proxies['{0}'].invoke.apply(proxies['{0}'], $.merge([\"{1}\"], $.makeArray(arguments)));", hubName, method.Name).AppendLine();
sb.Append(" }");
}
protected virtual string MapToJavaScriptType(Type type)
{
if (!type.IsPrimitive && !(type == typeof(string)))
{
return "Object";
}
if (type == typeof(string))
{
return "String";
}
if (_numberTypes.Contains(type))
{
return "Number";
}
if (typeof(IEnumerable).IsAssignableFrom(type))
{
return "Array";
}
if (_dateTypes.Contains(type))
{
return "Date";
}
return String.Empty;
}
protected virtual string Commas(IEnumerable values)
{
return Commas(values, v => v);
}
protected virtual string Commas(IEnumerable values, Func selector)
{
return String.Join(", ", values.Select(selector));
}
protected static string GetTemplateFromResource()
{
//this must remain "DefaultJavaScriptProxyGenerator" because the resource "Microsoft.AspNet.SignalR.Scripts.hubs.js" lives there
using (Stream resourceStream = typeof(DefaultJavaScriptProxyGenerator).Assembly.GetManifestResourceStream(ScriptResource))
{
var reader = new StreamReader(resourceStream);
return reader.ReadToEnd();
}
}
protected virtual string JavaScriptEncode(string value)
{
value = JsonConvert.SerializeObject(value);
// Remove the quotes
return value.Substring(1, value.Length - 2);
}
}
[AttributeUsage(AttributeTargets.Method, Inherited = false, AllowMultiple = false)]
public sealed class HubMethodExcludeFromProxyAttribute : Attribute
{
}
}
Now all you need to do is all a decorator to your hub methods, such as:
public class MyHub : Hub
{
[HubMethodExcludeFromProxy]
public void NotGeneratedOnClient()
{
}
public void GeneratedOnClient()
{
}
}
EDIT : There is an issue with dependency injection where if you have two different instances of a resolver, one in the GlobalHost.DependencyResolver and one in the Signalr configuration, it will cause remote methods to sometimes not work. Here is the fix:
//use only !ONE! instance of the resolver, or remote SignalR functions may not run!
var resolver = new CustomDependencyResolver();
GlobalHost.Configuration.DependencyResolver = resolver;
map.RunSignalR(
new HubConfiguration() {
Resolver = resolver;
}
);
Reference: https://github.com/SignalR/SignalR/issues/2807