Simple Slideshow using timer, javascript and JQuery

Here is the code to create a simple slideshow using timer, JavaScript and JQuery.

The html file contents should be like this which has all the images to show up.

<div class="galleryImages">
<img src='Images/Slides/0.png' alt="" />
<img src='Images/Slides/1.png' alt="" />
<img src='Images/Slides/2.png' alt="" />
<img src='Images/Slides/3.png' alt="" />
</div>
 The 'galleryImages' class is defined like this.

.galleryImages {
position: relative;
height: 350px;
width:700px;
overflow: hidden;
border:solid;
border-color:black;
border-width:thin;
-moz-border-radius: 15px;
-webkit-border-radius: 15px;
-khtml-border-radius: 15px;
border-radius: 15px;
margin:10px;
}
 .galleryImages img {
position: absolute;
top: 0;
left: 0;
}


The JavaScript code should be like this.

var slideShowTimer;
var imageId = 0;
var galleryImages;
var transitionSpeed = 500;
function PerformInitialization() {
SetupTimer();galleryImages = $('.galleryImages img');
}
 function SetupTimer() {
slideShowTimer = setInterval(ChangePhoto, 3000);
}
 function ChangePhoto() {
galleryImages.eq(imageId).stop(true, true).animate({ opacity: 0 }, transitionSpeed);
imageId++;if (imageId >= galleryImages.length) {
imageId = 0;
}galleryImages.eq(imageId).stop(true, false).animate({ opacity: 1 }, transitionSpeed);
}
Make sure to call PerformInitialization() function during "onload" of the body of the html file.

Also make sure to add these "JQuery" references.

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jQuery/jquery-1.5.1.min.js"></script>

<script type="text/javascript" src="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.10/jquery-ui.min.js"></script>
   
<link href="http://ajax.aspnetcdn.com/ajax/jquery.ui/1.8.10/themes/flick/jquery-ui.css" rel="stylesheet" type="text/css" />

Have fun. Happy coding.

Cheers
Adam

Attaching to an Event Trigger in Silverlight

There was a case in one of my projects to get notified whenever a Side Panel Visibility is changed.

For example, when a Panel Visibility state changes from "Collapsed" to "Visible" or from "Visible" to "Collapsed" we wanted a function to be called.

Here is the code to achieve this.

This line tells how to register it.

RegisterForNotification("Visibility", SidePanel, SidePanelVisibilityChanged);

Here is the function "RegisterForNotification".

public void RegisterForNotification(string propertyName, FrameworkElement element, PropertyChangedCallback callback)
{//Bind to a depedency property
Binding b = new Binding(propertyName) { Source = element };

var prop = System.Windows.DependencyProperty.RegisterAttached( "ListenAttached"+propertyName, typeof(object), typeof(UserControl), new System.Windows.PropertyMetadata(callback));
 
element.SetBinding(prop, b);
}
This is the callback function which will be called whenever the visibility state changes.

private void SidePanelVisibilityChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{  if (e.NewValue != null)
  {   if (e.NewValue.ToString() == "Collapsed")
   {     // Do something for collapsed... 
    }
  }
}
Hope this helps you.

Enjoy coding !

Cheers
Adam   

Using HTTP Modules

HTTP Modules are assemblies which can be called during every http request.

This comes in very handy when there is a need to intercept every request that comes into the Web application.

This is basically a simple class that is derived from IHttpModule interface.

Here is the sample code. This will be compiled to a DLL file.

public class MyClass : IHttpModule

{
        /// <summary>
        /// This is the disposing function.
        /// </summary>
        void IHttpModule.Dispose()
        {

        }

        /// <summary>

        /// This is the initialization function.
        /// </summary>
        /// <param name="context">This is the httpApplication context.</param>
        void IHttpModule.Init(HttpApplication httpApp)
        {
            httpApp.BeginRequest += new EventHandler(context_BeginRequest);
        }

        /// <summary>
        /// This is where the Begin Request Action is taking place.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void context_BeginRequest(object sender, EventArgs e)
        {
            HttpApplication httpApp = (HttpApplication)sender;
            RequestManipulation(httpApp);
        }

        /// <summary>

        /// This is the core function which tries to alter the request.
        /// </summary>
        private void RequestManipulation(HttpApplication httpApp)
        {
                    AlterNameValueCollection(httpApp);
        }

       /// <summary>

        /// Writes details of the Form NameValueCollection in the REQUEST object.
        /// </summary>
        /// <param name="httpApp">This is the input HttpApplication context from which the request header details will be written out.</param>
        private void AlterNameValueCollection(HttpApplication httpApp)
        {
            NameValueCollection postInfo = httpApp.Request.Form;
            System.Reflection.PropertyInfo prop = httpApp.Request.Form.GetType().GetProperty("IsReadOnly", System.Reflection.BindingFlags.Instance | System.Reflection.BindingFlags.NonPublic);
            // Set the property false (writable)
            prop.SetValue(httpApp.Request.Form, false, null);
            foreach (String eachKey in postInfo.AllKeys)
            {
                string towrite = string.Format("Key : {0} - Value : {1}", eachKey, httpApp.Request.Form[eachKey]);
                Helper.WriteinFile(towrite);
                if (eachKey == "AuthorName")
                {
                    Helper.WriteinFile("Before Changing AuthorName value....");
                    string oldValue = httpApp.Request.Form[eachKey].ToString();
                    httpApp.Request.Form[eachKey] = "MyClass Success. The old value '" + oldValue + "' was modified by the MyClass dll." ;
                    Helper.WriteinFile("Just now changed the AuthorName value.");
                }
            }
        }
}

After this code is compiled, copy the DLL file to the "bin" folder of the ASP.NET application on which the requests should be intercepted.

This DLL will be loaded into memory by using the following entries in the "Web.Config" file.

  <system.webServer>

    <modules>
      <add name="MyClass" type="MyNamespace.MyClass, MyClass, Version=1.0.0.0, Culture=neutral, PublicKeyToken=77ced88f9fdf21cb" preCondition="managedHandler,runtimeVersionv4.0" />
    </modules>
  </system.webServer>

 

This DLL can also be installed in the "Global Assembly Cache" and the above entries should load it automatically.

Hope this blog helps.

Happy coding !

Cheers
Adam  

 

 

Getting ASP.NET page values from Silverlight

There was a need to obtain values from the ASP.NET page to Silverlight application.

This is the function that can get the value.

private string GetHtmlElementValue(string htmlElementId)

{
   string togoElementValue = "";
   HtmlDocument doc = HtmlPage.Document;
   if (doc == null)
   {
     MessageBox.Show("Html Document is null.","Error", MessageBoxButton.OK);
      return togoElementValue;
   }
   HtmlElement elm = doc.GetElementById(htmlElementId);
   if (elm == null)
   {
     MessageBox.Show("Html Element " + htmlElementId + " is null.", "Error", MessageBoxButton.OK);
     return togoElementValue;
   }
     togoElementValue = elm.GetAttribute("value");
     return togoElementValue;
}

This is how the function should be called.

GetHtmlElementValue("AuthenticationTypeField");

This will come in handy when we need to pass the information from ASP.NET page to Silverlight Application.

Hope this helps.

Cheers
Adam


   

Log File not written during scheduled task execution in Python Script

I wrote a python script to perform a scheduled job. I was also logging few information in a simple text file. But for some reason, nothing was written in the log file.

After doing some research, I found that, when setting up the scheduled task, I must fill in the "Start In" folder location. Only when this value is set, the python script can write the log file correctly.

Hope this helps !

Happy Coding.

Intercept calls coming to a Web Application in IIS Server

It was required to intercept all the calls coming into a particular web application on the IIS Server and identify the contents in the request. We ended up writing a class derived from “IHttpModule" interface.

Here are some tips on how to create and install it on the IIS server.

• Creating the class is a simple task. Just derive the class from the interface “IHttpModule". Implement the interface as shown below.

public class ServerIntercept : IHttpModule
{
      public void Dispose()
       {
       }
       public void Init(HttpApplication context)
       {
        context.BeginRequest += context_BeginRequest;
        }
        void context_BeginRequest(object sender, EventArgs e)
        {
            // Add all code here
        }
}

• Make sure the DLL is signed with strong name key
• Copy this DLL to the server and use GAC utility to register this on the server.  If it is .NET 2 framework it is a different utility and if it is .NET 4 framework it is a different utility. Use the correct utility to register.
• Add the entries to the Web.Config file of the application. This file may be read-only. Make sure the entries are being saved properly. A sample is shown below.

<configuration>
<system.webServer>
<modules>
<add name="ScriptModule-4.0" type="System.Web.Handlers.ScriptModule, System.Web.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" preCondition="managedHandler,runtimeVersionv4.0" />
</modules>
</system.webServer>
</configuration>

 The type in the above example is the class name with namespace and the DLL file name. The public key token value can be obtained from the GAC utility.

• Reset IIS. Then open the IIS manager. Go to the application and look into the “Modules” section. The newly installed module must be present and now the application is ready to intercept all the calls coming to it.

Happy coding!