Asp.NET user Control tips

Irfan Munir — Sat, 05 Jul 2008 11:02:42 +0000

Shahed Khan (MVP)

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I am a Microsoft Certified Application Developer MCAD Chartered Member (C# .Net) and born in Bangladesh.
I work for Ocean Informatics Pty Ltd as a Senior Developer - Analyst.
I am also co-founder and core developer of Pageflakes www.pageflakes.com
and most recently created SmartCodeGenerator

My Articles

Flexible and Plugin based .Net Application..

Mass Emailing Functionality with C#, .NET 2.0, and Microsoft® SQL Server 2005 Service Broker’

Write your own Code Generator or Template Engine in .NET

Smart Code Generator .NET: Usage Overview

Smart Code Generator .NET: Architectural Overview
Smart Code Generator .NET: using with NAnt and Cassini

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Thursday, June 26, 2008

ASP.NET tips: Golden rules for Dynamic Controls.

1. Make sure your dynamic controls are Loaded on every postback.

Lets play with a very simple example,

ASPX

<%@ Page Language=”C#” AutoEventWireup=”true” CodeFile=”Default.aspx.cs” Inherits=”_Default” %>

C# Code Behind

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
TextBox t = new TextBox();
t.ID = “textBox”;
this.PlaceHolder1.Controls.Add(t);
}

}

The above code works fine, but a common mistake is to try to conditionally load dynamic controls, if we tweak the code a little bit you will notice we loose our TextBox after any postback. The following code will not load the TextBox after our first postback.

public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
TextBox t = new TextBox();
t.ID = “textBox”;
this.PlaceHolder1.Controls.Add(t);
}
}

}

Its recommended to load the dynamic controls during the Page_Init instead, because we may want to hook up our events with proper handler at an early stage.

public partial class _Default : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e)
{
TextBox t = new TextBox();
t.ID = “textBox”;
t.TextChanged+=new EventHandler(t_TextChanged);
this.PlaceHolder1.Controls.Add(t);
}

}

2. Do not assigning properties of a dynamic control (viewstate enabled), during Page_Init, it will not be reflected.

Here is scenario of another common mistake, “123″ assigned to the Text property during Page_Init,

public partial class _Default : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e)
{
TextBox t = new TextBox();
t.ID = “textBox”;
t.Text = “123″;
this.PlaceHolder1.Controls.Add(t);
}

}

the above code will not work because, Initialization happens before LoadViewState during the control lifecycle. The value assigned to the properties during Initialization will simply get overwritten by the ViewState values.

3. If you are expecting your ViewState to retain after the postback, always assign same ID to the dynamic control

The following piece of code will not work, as I am assigning a new ID to the dynamic control after each postback. The LoadViewState retrieves previously saved viewstate data using the control ID, as the control ID has changed, it doesn’t know anymore what to load, as a result it cannot load previously saved viewstate data any more.

public partial class _Default : System.Web.UI.Page
{
protected void Page_Init(object sender, EventArgs e)
{
TextBox t = new TextBox();
t.ID = Guid.NewGuid().ToString();
this.form1.Controls.Add(t);
}
}

Thank you for being with me so far.

posted @ Thursday, June 26, 2008 2:36 AM | Feedback (0) |

Tuesday, June 17, 2008

ASP.NET tips, Making Custom Validators work in Partial Rendering mode.

Introduction

There are many situations where we need to identify if partial rendering is supported in a page, especially when a control uses javascript, to get the control work in partial rendering mode, the script needs to be registered using a ScriptManager Type instead. A classic example will be Validators.

The ASP.NET Page class exposes the Validators property, which is a list of all the IValidator types on the page. A page keeps track of its validators, and registers a javascript array of validators automatically to the page. Example, When we add 3 RequiredFieldValidator in a page the following javascript Array will be automatically generated and added in our page automatically during the page load.

Page_Validators = new Array(document.getElementById(”RequiredFieldValidator1″),
document.getElementById(”RequiredFieldValidator2″),
document.getElementById(”RequiredFieldValidator3″));

The ASP.NET Page also registers couple of other script which eventually hooks up different events ( onclick, onkeypress, onchange, onblur ) to the the target control (ControlToValidate), to some predefined javascript functions that resides in WebUIValidation.js file. So when we add a validator in our Page we also notice the following script is automatically added. [WebUIValidation.js ships with ASP.NET and resides in the following folder "/aspnet_client/system_web//WebUIValidation.js".]

ValidatorOnLoad plays the big role of hooking up the the events mentioned above, and here is a code snippet from this function,

for (i = 0; i < Page_Validators.length; i++) {
val = Page_Validators[i];
if (typeof(val.evaluationfunction) == “string”) {
eval(”val.evaluationfunction = ” + val.evaluationfunction + “;”);
}
…

if (typeof(val.controltovalidate) == “string”) {
ValidatorHookupControlID(val.controltovalidate, val);
}
…
}

keen eyes may have already noticed the val.evaluationfunction property, yes every validators needs to have this property for it to work properly under the ASP.NET validation framework. Custom validators takes advantage of this property to point to custom js functions. Custom validator developers normally use RegisterExpandoAttribute method to register this attribute.

Problem
When I used Update Panel with partial rendering enabled the Page.ClientScript.RegisterExpandoAttribute did not work for me. My validators always stopped working after the first postback, which was performed via partial rendering and triggering. I found the “evaluationfunction” in the javascript to be undefined.

Solution
I started looking under the hood, and soon discovered, that the ASP.NET Validators that ships out of the box, ( eg. RangeValidator, RequiredFieldValidator ) uses a different internal method “AddExpandoAttribute” to register the property. Here is a code snippet from the RangeValidator.

protected override void AddAttributesToRender(HtmlTextWriter writer)
{
base.AddAttributesToRender(writer);
if (base.RenderUplevel)
{
string clientID = this.ClientID;
HtmlTextWriter writer2 = base.EnableLegacyRendering ? writer : null;
base.AddExpandoAttribute(writer2, clientID, “evaluationfunction”, “RangeValidatorEvaluateIsValid”, false);
…
}
}

and code snippet from BaseValidator, the internal method AddExpandoAttribute.

internal void AddExpandoAttribute(HtmlTextWriter writer, string controlId, string attributeName, string attributeValue, bool encode)
{
AddExpandoAttribute(this, writer, controlId, attributeName, attributeValue, encode);
}

After digging further I realized, AddExpandoAttribute checks the ASP.Page whether partial rendering is supported, then it registers the attribute using ScriptManager instead. I did the same with my validation control and it works for me. Here is the piece of code that solved my problem.

protected override void AddAttributesToRender(System.Web.UI.HtmlTextWriter writer)
{
base.AddAttributesToRender(writer);
if (this.RenderUplevel)
{
string clientID = this.ClientID;
if (!this.IsPartialRenderingSupported)
{
Page.ClientScript.RegisterExpandoAttribute(clientID, “evaluationfunction”, “EntryValidatorEvaluateIsValid”);
}
else
{
Type scriptManagerType = BuildManager.GetType(”System.Web.UI.ScriptManager”, false);
scriptManagerType.InvokeMember(”RegisterExpandoAttribute”, BindingFlags.InvokeMethod | BindingFlags.Public | BindingFlags.Static, null, null, new object[] { this, clientID, “evaluationfunction”, “QuantityEntryValidatorEvaluateIsValid”, false });
}
}
}

Note, the I am first checking whether Partial Rendering is Supported and using the ScriptManager Type to register the property instead.

The following piece of code uses Reflection to figure out whether partial rendering is supported.

internal bool IsPartialRenderingSupported
{
get
{
if (!this.PartialRenderingChecked)
{
Type scriptManagerType = BuildManager.GetType(”System.Web.UI.ScriptManager”, false);
if (scriptManagerType != null)
{
object obj2 = this.Page.Items[scriptManagerType];
if (obj2 != null)
{
PropertyInfo property = scriptManagerType.GetProperty(”SupportsPartialRendering”);
if (property != null)
{
object obj3 = property.GetValue(obj2, null);
this.IsPartialRenderingEnabled = (bool)obj3;
}
}
}
this.PartialRenderingChecked = true;
}
return this.IsPartialRenderingEnabled;
}

}

private bool PartialRenderingChecked
{
get
{
object val = ViewState["PartialRenderingChecked"];
if (val != null)
return (bool)val;
return false;
}
set
{
ViewState["PartialRenderingChecked"] = value;
}
}

private bool IsPartialRenderingEnabled
{
get
{
object val = ViewState["IsPartialRenderingEnabled"];
if (val != null)
return (bool)val;
return false;
}
set
{
ViewState["IsPartialRenderingEnabled"] = value;
}
}

Conclusion

The Page.ClientScript.RegisterExpandoAttribute may not work in Partial Rendiring mode, when a postback is performed via triggering,
to get this work we need to determine whether partial rendering is supported and use the ScriptManager Type instead like described above.

Hope this helps, and saves some of your time, Thank you for being with me so far.

posted @ Tuesday, June 17, 2008 5:43 AM | Feedback (0) |

Wednesday, June 11, 2008

C# 3.0 tips, Automatic Property

Declaring a property in C# 3.0 is super easy and super short.

public class Student
{
public string Name { get; set; }
}

yes that’s it, the framework will take care of the rest, the private variables will be automatically created and the getter and setter will be automatically implemented.

Here is how we can assign value to an automatic property via the constructor

public class Student
{
public string Name { get; set; }
public Student (string name)
{

this.Name = name;

}
}

And finally, here is how we can declare a Readonly property

public class Student
{

public string Name { get; private set; }

public Student (string name)
{

this.Name = name;

}
}

Hope this helps, Enjoy coding.

posted @ Wednesday, June 11, 2008 12:21 AM | Feedback (0) |

Monday, June 09, 2008

System.Net.WebClient().DownloadString(url) for Web Scrapeing

WebRequest is the abstract base class for the .NET Framework’s request/response model for accessing data from the Internet.

To get content of a website, in .NET 1.0. we used to use WebRequest, which is good and also works asynchronously.

public static string GetContent(string url)
{
System.Net.WebRequest request = System.Net.WebRequest.Create(url);
using (System.Net.WebResponse response = request.GetResponse())
{
using (System.IO.StreamReader reader =new System.IO.StreamReader(response.GetResponseStream()))
{
return reader.ReadToEnd();
}
}
}

But in .NET 2.0, we can also use the WebClient class. It can also work asynchronous and works the same as the other one.

public static string GetContent(string url)
{
using (System.Net.WebClient client =new System.Net.WebClient())
{
return client.DownloadString(url);
}
}

We can use any of the above method for web scrapeing in .NET. But the second approach is probably more cleaner.

posted @ Monday, June 09, 2008 3:28 PM | Feedback (0) |

Friday, May 23, 2008

Project SOAK winner of 2008 Imagine Cup Australia.

The theme of this year’s Imagine Cup is “Imagine a world where technology enables a sustainable environment.” It had been a great honorary for me to take part as one the Judges of the 2008 Imagine Cup Australia. All the teams worked real hard and came up with breathtaking solutions. The interesting part was solutions were built on top of cutting edge technologies technologies ie. Silverlight, Virtual Earth, LINQ, ASP.NET 3.5, WCF, .NET 3.5 and SQL2005.

The Project SOAK is announced the winner of Australian Imagine Cup 08. SOAK which stands for “Smart Operational Agriculture toolKit” is an integrated hardware and softwares platform that aims to help farmers make the most of the water (and other) resources on their land. It does this through an integration of a wide range of sensors which gathers data about the environment in real time, provide rich visual information to end-user about the status of the farm, and electronically controls various systems such as sprinklers. The team members of SOAK blogged more about the project, can be found here

http://davidburela.wordpress.com/2008/05/22/2008-imagine-cup-australian-winner-project-soak/

http://www.istartedsomething.com/20080523/imagine-cup-australian-winner-project-soak/

Australian PC Magazine has just published published a very insightful story on this project and the competition

I found SOAK to be a brilliant piece of work, where the team combined latest technologies together and came up with a environment friendly cost effective solution.

The winning team will now represent Australia at the World Imagine Cup finals in Paris in July.

Imagine Cup 2008 - Australia - Judging Panel

The Imagine Cup’s judging panel consisted of Roger Lawrence, Microsoft Australia’s Manager Developer Evangelism; Nigel Watson, Microsoft Australia Architect Evangelist; Shekhar Kalra, computer science lecturer at RMIT University; Shahed Khan, Senior Software Engineer at Ocean Informatics MVP C#.NET, and APC, represented by its editor, Tony Sarno.

posted @ Friday, May 23, 2008 11:41 PM | Feedback (0) |

Saturday, May 03, 2008

ASP.NET Bug, Multi View control do not save ViewState, of dynamically added controls

Couple of days back me and my colleague, we discovered an issue with the ASP.NET Multi View Control.
We were surprised to see that it do not add ViewState, of the dynamically added controls, of the Inactive Tabs.

ASP.NET 2.0

C# Code Behind

if (!IsPostBack)
{
int index = 1;
foreach (View v in MultiView1.Views)
{
TextBox t = new TextBox();
t.ID = index.ToString();
t.Text = “This text will not be assigned, to any Inactive Tabs, unless you put a breakpoint on this line and watch the value of this line explicitly“;
v.Controls.Add(t);
index = index + 1;
}
}

Surprisingly, you will notice only the Textbox.Text of the Active Tab will have value,
however if you go to any other Tab of the MultiViewControl, you will notice that the TextBoxes are empty.

After investigating further we realized that the Viewstates of the dynamically added controls are not saved (for any of the inactive tabs).
It became more interesting, when we started to debug, by putting a breakpoint to watch TextBox.Text, surprisingly every TextBox gets populated with desired Text ( for all tabs including the inactive tab, only when you explicitly watch ). Also it saves all ViewState correctly.

Not sure whether its a bug, the ASP.NET team may have wanted this behavior to enhance performance of the Multi View control,

but if that is the case, why does it populate the TextBox.Text and also saves into Viewstate, when we try to debug !!!

Do not believe me? Try it by yourself !!

posted @ Saturday, May 03, 2008 3:31 AM | Feedback (1) |

Monday, April 28, 2008

ASP.NET in VISTA ( IIS7 ) with VS2005 or VS2008

The following 2 links may help.

VS 2005: http://learn.iis.net/page.aspx/431/using-visual-studio-2005-with-iis-70/
VS 2008: http://learn.iis.net/page.aspx/387/using-visual-studio-2008-with-iis-70/

posted @ Monday, April 28, 2008 4:13 PM | Feedback (0) |

Saturday, April 12, 2008

ASP.NET Tips: Using Image as Embedded Resource for ASP.NET CustomControl

Problem

I started writing an ASP.NET Custom Server Control, where I wanted an Image to be Embedded Resource of the Assembly itself,
so that, I do not need to ship the images separately, but surprisingly it did not work straightway for me.

The following line was not working for me:
writer.AddAttribute(HtmlTextWriterAttribute.Src, Page.ClientScript.GetWebResourceUrl(typeof(MyControls.MyImageControl), “ferrari.jpg”));

Ok, lets elaborate what I did and what I missed,

Step 1, I created my ClassLibrary project, added an Image, added a Custom Control class.

Step 2, Made the image an embedded resource of the Assembly.

Step3, Written my very simple Custom Control, where I assigned the image “src” to the WebResource URL

Step 4, Then I wanted to tryout this CustomControl in my Test Website

Step 5, But I got the following result.

Solution

After investigating a bit, I realized I missed some critical bits.

1. I did not put the correct Resource URL. I discovered this by opening up the assembly via Reflector, I found that the resource URL is different than what I have put in my code.

I corrected the resource URL in my code, (but still it did not work).

writer.AddAttribute(HtmlTextWriterAttribute.Src,
Page.ClientScript.GetWebResourceUrl(typeof(MyControls.MyImageControl),
“MyControls.images.ferrari.jpg”));

2. I investigated further and found that I did not explicitly declare the image as WebResource in my assembly info . To get the embedded resource bit working, the following line is very important, and this solved my problem.

[assembly: System.Web.UI.WebResource("MyControls.images.ferrari.jpg", "image/jpg")]

Note: We can also put this directly in the class file itself.

After the fix I got the following result as I have desired.

Summary

I have discussed here, how to embed image in an Assembly and how to use it as WebResource. Two points to note here, which are
1. After embedding a resource it is very important to explicitly declare itself as WebResource in the assembly,
2. We need correct resourceURL to access resouces from the assembly. Note: its case-sensitive as well.

I hope this discussion will save you some time. Thank you for being with me so far.

posted @ Saturday, April 12, 2008 8:45 PM | Feedback (0) |

Saturday, March 22, 2008

DataTable to JSON and ToJSON() Extension

Very recently I wrote an application where I had to deal with DataSet from a Web Service.

Please note, I have no control on the Web Service and I ended up writing a small function which converts DataTable to JSON.

I understand I haven’t gain anything on the web traffic, but it surely simplified my JavaScript programming.

Let me go through what I did

Step 1. Extract the XML Schema.
DataTable has two handy methods to extract Xml and Xml Schema. I extracted the Xml Schema to be able to generate a C# class using the xsd.exe.

string path = “Your File Path”;
myDataTable.WriteXml(path);
myDataTable.WriteXmlSchema(path);

Step 2. Generate C# Class using Xsd.exe that ships with the .NET Framework.

C:\temp>xsd mydatatable.xsd /l:cs /c
Microsoft (R) Xml Schemas/DataTypes support utility
[Microsoft (R) .NET Framework, Version 2.0.50727.42]
Copyright (C) Microsoft Corporation. All rights reserved.
Writing file ‘C:\temp\mydatatableclass.cs’.

Step 3. DataTable to Object conversion

The Web Service returns DataSet/ DataTable, and I want to transform all data that I I receive in the DataTable, to an instance of the class that I just generated in the above step. Something like this:

private T DataTableToT(DataTable dataTable, T obj)
{
using (MemoryStream ms = new MemoryStream())
{
dataTable.WriteXml(ms);
Type thetype = obj.GetType();
XmlSerializer x = new XmlSerializer(thetype);
ms.Position = 0;
return (T)x.Deserialize(ms);
}
}

The above method uses the WriteXml() to write the data of DataTable in to a MemoryStream, then using the XmlSerializer I deserialize the xml to a .NET object. Here is how we may use the this method:

DataSet ds = WebService.GetDataSet();
DataTable myDataTable = ds.Tables[0];
MyDataTableClass obj = DataTableToT(myDataTable, new MyDataTableClass());

Step 4. Serialize .NET object to JSON

We have done the hard part above, now we have .NET object so we have all the flexibility as you can imagine. I found that there is a handful amount of libraries which can serialize .Net Objects to JSON string ie. JavaScriptSerializer, DataContractJsonSerializer, JSON.NET etc.

JavaScriptSerializer ships with System.Web.Extensions.dll and you can locate it under Namespace: System.Web.Script.Serialization. The following method returns JSON from a .NET object using JavaScriptSerializer.

private string GetJSONUsingJavaScriptSerializer(T obj)
{
JavaScriptSerializer serializer = new JavaScriptSerializer();
string json = serializer.Serialize(obj);
return json;
}

DataContractJsonSerializer also does pretty much the same as above, it ships with .NET Framework 3.5 : System.ServiceModel.Web.dll, and you can locate this under Namespace: System.Runtime.Serialization.Json, But we need to decorate the class with DataContract and DataMember attributes. Example

[DataContract]
class Order
{
[DataMember]
public int OrderID { get; set; }
[DataMember]
public DateTime OrderDate { get; set; }
}

and the following method can return a JSON string.

private string GetJSONUsingDataContractJsonSerializer(T obj)
{
using (MemoryStream ms = new MemoryStream())
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
serializer.WriteObject(ms, obj);
return Encoding.UTF8.GetString(ms.ToArray());
}
}

Conclusion

Here we have discussed how we can easily transform a DataTable to JSON. Sometimes we do not have enough control over the Web Service, or we may need to invoke a legacy Web Service that returns DataSet/ DataTable. In those scenarios sometimes converting DataTable to JSON comes very handy in AJAX programming. In the above example I have shown plain vanilla .NET methods, but we can even take it further and implement Extention methods to return JSON string. Scott has shown in his blog how to produce JSON using JavascriptSerializer. Here I show how we can do the same using DataContractJsonSerializer.

Example:

public static string ToJSON(this T obj)
{
using (MemoryStream ms = new MemoryStream())
{
DataContractJsonSerializer serializer = new DataContractJsonSerializer(obj.GetType());
serializer.WriteObject(ms, obj);
return Encoding.UTF8.GetString(ms.ToArray());
}
}

and then we will be able to use it like this on a order collection,

string json = orders.ToJSON();

Hope this helps.

posted @ Saturday, March 22, 2008 5:31 PM | Feedback (1) |

Tuesday, March 18, 2008

Visual Studio 2005 Debugging in Vista

Problem: I was trying to debug in Visual Studio 2005 in my new machine which came with Vista Home Premium. Surprisingly I found that none of the break points are touched and I cannot debug. I tried giving all types of permission to the folder but no luck.

Solution: After googling a bit, I found that I needed to run VisualStudio2005 as an Administrator, and everything started working as I expected.

So all I had to do is :
Right-click the Visual Studio icon and select the “Run as administrator” option from the context menu.

Hope this saves some of your time.

posted @ Tuesday, March 18, 2008 2:39 PM | Feedback (1) |

Thursday, February 21, 2008

Javascript Tips: Carefully use “this” when writing classes, else you may cause memory leak.

Lets say we want to declare a class in Javascript, which is equivalent to the following C# class.

public class Student
{
  public string FirstName = "";
  public string LastName = "";

  public Student( string firstname, string lastname)
  {
    this.FirstName = firstname;
    this.LastName = lastname;
  }

  public string GetFullName()
  {
    return FirstName + LastName;
  }
}

To write a similar class in JavaScript we can do something like the following [ but this will create memory leak, I am explaining that in a moment ]

function Student ( firstname, lastname)
{
  this.FirstName = firstname;
  this.LastName = lastname;

  this.GetFullName = function()
  {
    return this.FirstName + this.LastName;
  }

}

now in C# if we want to instantiate an object of Student and want to call the GetFullName() method, we do the following.

Student student = new Student("Shahed", "Khan");
string fullname = student.GetFullName();

and we can create as many objects as we want and call its methods, each of the object will maintain its own state, and all objects will use the same copy of the GetFullName() method.

But Javascript has different behaviour when we do the following on the above Javascript class.

var student = new Student("Shahed","Khan");
car fullname = student.GetFullName();

In Javascript, functions are treated as variables as a result when we create a new object of Student it creates new sets of firstname, lastname and also a new copy of GetFullname method, as a result we are creating memoryleak.

Do not worry too much, there is a workaround for this, lets redefine the class in a different way.

function Student ( firstname, lastname)
{
  this.FirstName = firstname;
  this.LastName = lastname;

  this.GetFullName = GetFullName;

}

function GetFullName()
{
  return this.FirstName + this.LastName;
}

Notice I have moved the GetFullName function out of the class, and for this tweaking all new objects of the Student class will share the same instance of of GetFullName method and avoid memory leak.

Thank you for being with me so far.

Updated 24th Feb

===============

Laurent from Galasoft gave some good feedback,

JavaScript object oriented should be done by modifying the prototype property of the object, and never by storing methods using the “this” keyword. The workaround provided above is not good practice, as it forces the use of a global function. We should always declare methods in JavaScript object like this:

function Student(firstName, lastName)

{

this.firstName = firstName;

this.lastName = lastName;

}

Student.prototype =

{

getFullName : function()

{

return this.firstName + ” ” + this.lastName;

}

also note correct naming convension, ( Javascript follows Java notation not C#). For JavaScript best practices please refer to the work of Microsoft Silverlight team.

posted @ Thursday, February 21, 2008 5:38 PM | Feedback (1) |

Tuesday, February 19, 2008

Solving DNN deployment issues, Redirecting to localhost and Running DNN in a different port

I was trying to host a small DNN application in one of our Server and I was facing couple of issues.

Problem 1:
The first problem I faced is it was always redirecting to localhost, whenever I tried http://domain.com/dnn it was redirecting to http://localhost/dnn as a result the site was un-accessible from outside.

Solution

This was easy to solve.
1. I needed to log in as host account.
2. Then I needed to go to the Admin > Site Settings page
3. And finally In the Portal Alias section I added a new Http Alias “domain.com/dnn”

This solved my problem when I hosted the site in port 80.

Problem 2:

Now I tried to host the application in a different port 8080. I.e. http://domain.com:8080/dnn. and somehow when I clicking to redirect to any other page the port started to disappear. The http://domain.com:8080/ automatically turned to http://domain.com/ .

Solution

After googling and looking at the web.config carefully I found, its clearly documented in web.config that

–>

I tweaked my appsettings section and added the magic key

Also I had to add a new Http Alias “domain.com:8080″

This solved my problem and started retaining the port for my http://localhost:8080 but not http://domain.com:8080. The http://domain.com:8080 was still turning to http://domain.com

Note: I later discovered this was not a problem of DNN and the issue happened because of the setup of our router settings and port forwarding, which I’ll discuss next.

Problem 3:
Even after adding the “UsePortNumber” key it did not solve my problem

Solution

Our Router was Port Forwarding all traffic of 8080 to the port 80 of the machine where DNN app is hosted. I.e. 8080 –> 80. As a result even from a browser I as typing http://domain.com:8080 , the DNN Request object was getting http://domain.com and when DNN handlers and url rewriters spitting the reformatted url it was spitting http://domain.com.

This was a big problem for me, initially I thought I would write a HttpHandler for 404 page not found, but soon realized it will never hit the server with the spitted Url so that didn’t work. Then I thought I would tweak the DNN handlers to handle this scenario, but later tweaked the IIS and Router to handle this.

1. In IIS I added, support for 8080 to my Default Website.

2. In Router instead of forwarding to port 80 I started forwarding 8080 to 8080.
3. Made sure that in my DNN Site Settings, I have added Http Alias “domain.com:8080/dnn”.

Waaa la, This solved my issue.

Hope this helps and Thank you for being with me so far.

posted @ Tuesday, February 19, 2008 5:14 PM | Feedback (2) |

Thursday, February 14, 2008

Dotnet Nuke Tips: Two common error while writing the SqlDataProvider

Two common errors done while writing the SqlDataProvider SQL for Dotnet Nuke Modules are

1. Not saving the file that contains SqlDataProvider SQL codes in the correct format. A quick trick is to open the files in NotePad and save them as “Unicode”.

2. Not putting atleast 2 line breaks after each GO statement in the SQLDataProvider SQL code.

Hope this helps.

posted @ Thursday, February 14, 2008 1:00 PM | Feedback (0) |

Wednesday, February 06, 2008

LINQ Tips: Implementing IQueryable Provider

Check out the following from Matt Warrens blog posts, if you are interested on how to implement IQueryable Provider.

source: http://blogs.msdn.com/mattwar/archive/2007/07/30/linq-building-an-iqueryable-provider-part-i.aspx

Part I - Reusable IQueryable base classes
Part II - Where and reusable Expression tree visitor
Part II - Local variable references
Part IV - Select
Part V - Improved Column binding
Part VI - Nested queries
Part VII - Join and SelectMany

posted @ Wednesday, February 06, 2008 5:50 PM | Feedback (0) |

Tuesday, February 05, 2008

LINQ Tips: Querying ArrayList via LINQ

Problem
If you try to query an ArrayList via LINQ you might be surprised to see that its not supported and throwing an exception. In other words the following query will not work at all.

ArrayList students = GetStudents();
var query =
from student in students
where student.Score > 80
select new { student.ID, student.Name };

Cause
The problem comes from the fact that LINQ to Objects has been designed to query generic collections that implement the System.Collections.Generic.IEnumerable interface. Where an ArrayList is a nongeneric collection that contains a list of untyped objects and also does not implement IEnumerable.

Solution
Cast operator comes into rescue.

Here is the signature of the Cast operator:
public static IEnumerable Cast(this IEnumerable source)

Cast can take a nongeneric IEnumerable and returns a generic IEnumerable.
A modification of the above query like this will solve the problem and you will be able to query ArrayList via LINQ.

ArrayList students = GetStudents();
var query =
from student in students.Cast()
where student.Score > 80
select new { student.ID, student.Name };

posted @ Tuesday, February 05, 2008 4:30 PM | Feedback (1) |

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Dotnet Nuke Tips: Two common error while writing the SqlDataProvider

LINQ Tips: Implementing IQueryable Provider

LINQ Tips: Querying ArrayList via LINQ