Runtime Debugger - kannan M ambadi's blog

Improve ASPX web page performance by combining Skin & CSS

kannan.ambadi — Mon, 22 Jun 2009 02:57:00 GMT

There has been numerous discussions happened on web site performance, ranging from UI design to Site Hosting. Out of this, one of the important step is, to reduce the size of Http Response size. Optimizing Http Response will considerably reduce the page loading time at the browser. There are many ways to create optimized HTML markups to improve client-side performance. I would like to explain one such a way of designing web page. The Loading time factor will mainly depends on the web page size that is going to download at the client's browser. In order to achieve this as a web developer, you will have to work on the following things at least.

HTML -> Use XHTML markups with CSS always rather than using HTML tables with inline HTML style attributes unless it is required.
CSS -> Keep all your style definitions in an external stylesheet. It will make the page source clean and also reduce the Http Requests by caching these files at the client machine.

I don't want to discuss about JavaScript, since it might be deviating from the topic. As my title says, we can reduce the HTTP Response size by combining those two factors mentioned above with the help of Asp.Net Skin files.

As you know, Asp.Net 2.0 has introduced a new feature called Themes which helps to achieve consistent look and feel for websites. Themes may contain Skin files, CSS files, images etc. A Skin file is nothing but extensions of CSS definitions for the Asp.Net server controls. Themes and skins enables to handle style attributes from Application level to Control level. Skins are mainly used for Web controls such as Label, Button etc. There are two types of skin file, Default skin - which applies same style for all the controls of same type and Named Skin - which possess a SkinID property by which we can apply Style to the control's skinId. Here is an example for Skin file:

<asp:Button SkinID="buttonStyle" runat="server" BackColor="#2E132D" BorderColor="#507CD1" Height="25px" Width="120px"
BorderStyle='Solid' BorderWidth='1px' Font-Names='Verdana' Font-Size='11px' ForeColor='White' Font-Bold='true' />

The main disadvantage on Skin file is, it renders the pre-defined style definitions as inline HTML style attributes attached with the control to which skin is applied. Lets see the skin given above, it renders into the browser as follows

These chunks of HTML markups generates every time when the associated web control renders into the browser. Even though the ASPX part looks neat and clean, the HTML markups rendered at the browser may reminds the old Web 1.0 page(ie: html tags without CSS) and also results in large size of HTTP Response. Such pages will definitely affect the performance of the website. How can you avoid such scenario? Does it mean skin files are not good at website development? Will Css alone provide better performance? I would say no and definitely continue with skin files, but combined with CSS. In such case, we'll be writing most of the style definitions in CSS classes and link that class to skin by using a skin control property called CssClass. This time, the above skin style will look like as

<asp:Button SkinID="buttonStyle" runat="server" CssClass="normalButton" />

and it will render as

<input type='submit' class='normalButton' />

Did you see any difference? The chunks of HTML markups are gone!!!....The page size has reduced without removing skins, but by moving all style definitions into an external CSS file.

Technorati Tags: Asp.Net,HTML,CSS,Themes,Skins,HTTP Response,StyleSheet,Page Performance,Loading Time

ORM Technology - nHibernate vs Linq

kannan.ambadi — Fri, 16 Jan 2009 04:39:00 GMT

I'm back after some time away from my blog ;).. This time i would like to tell about my favourite "nHibernate" and ORM Technology. Not So Long Ago, i’ve attended a microsoft seminar on Visual Studio 2008 & VSTS. It was a nice presentation and we have had a delicious lunch too;)…Presentation on VSTS was amazing. The presenter, Tejsvi Kumar(Technology specialist from microsoft) , who provided clear idea on how we can handle a big project by Only using VSTS.Then he had shown demo on VSTS how Project manager can assign tasks, view status or create test cases on the fly etc. In between he also mentioned on visual studio 2008 features. i would to like express my appreciation to them for sharing their exp with us. And more than that, they’ve come up with more knowledge by replying our queries. Me too sent a mail regarding some queries on LINQ. I got a very detailed reply on this. I would like to share their reply with everyone since it provides a neat explaination on LINQ n other technologies.

Q : Can u differentiate between Ado.Net and LINQ
A : ADO.NET is a mechanism to connect to the data source (like ODBC) whereas LINQ is a query mechanism to query *any* kind of data not necessarily data from a database. As an example try the following simple LINQ program:

static void Main(string[] args)
{
int[] numbers = { 3, 5, 6, 1 };

var exp = from n in numbers

where n < 5
orderby n ascending
select n;foreach(var e in exp )
{
Console.WriteLine(e);
}
}

This program demonstrates the following:

- LINQ is a language concept (integrating queries in the programming language)
- LINQ queries can be quite expressive including joins, where clauses, grouping etc.
- LINQ has nothing to do with databases in particular – however you can build LINQ based extensions that enable you to to query any kind of database using LINQ queries (e.g. LINQ to XML, LINQ to SQL, LINQ to datasets, LINQ to Entities, LINQ to Objects)

Q : Is LINQ is nothing but a copy of nHiberante ?
A : I disagree - LINQ is NOT copied from nHiberbate. The example in point 1 will explain that nHibernate has nothing similar. However you can definitely compare LINQ-to-SQL with nHibernate. Now nHibernate itself is no new technology – both nHibernate and LINQ-to-SQL are products that make use of the Object Relational Mapping (ORM) Technology. There are pro and cons of ORM technology and they are very widely discussed in the technology circles. You can get an insight into them on the net. The important thing to remember is that there are definitely some very important benefits (inspite of some disadvantages) of ORMs and if as an architect your analysis proves that ORM wil benefit your project you should go for it. Generally every technology has its pros and cons (like any other thing in life) and as a smart Architect you need to understand your requirements in nicely and then choose the technology that suits you best.

Q : LINQ(nHiberante) causes difficulty while debugging the code. Its very difficult to find which line throws exception.
A : This statement confirms my comment in point 3. Pro of LINQ-to-SQL(nHibernate) – faster code development; Con of LINQ-to-SQL (nHibernate) – possibly more extensive debugging. However, if you make you of some best practices for debugging you can reduce the time.

Q : Its very difficult to make changes according to Database changes..
A : Actually, with ORMs it becomes easier to abstract the Database changes from Application changes. So if your application is architected correctly and there are DB changes – with LINQ-to-SQL (or nHibernate) you will need to do NO or almost minimum changes in your code (all you have to do is change the mapping layer)

Q : Performance is slow compared to ado.Net(i’ve checked wit nHibernate, not wit LINQ)
A : Please read my blog post on performance generally: http://blogs.msdn.com/bsinghal/archive/2007/07/16/there-is-a-performance-problem.aspx.
To compare the performance of LINQ v/s non-LINQ scenario – you will need to do very thorough testing and make sure that we compare apples to apples.Regarding performance is slow with nHibernate or LINQ-to-SQL (ORMs) as compared to ADO.NET – yes that can be true in some cases even after doing all the possible optimizations etc because ORMs do add an extra layer of processing but they provide a lot of flexibility in return. The point here is that one should analyse the technology properly and make sure that any technology they choose addresses their requirements and needs. So if you are ready to spend 10 times more time in developing the application in ADO.NET at the cost of gaining lets say 2% performance improvement and of that is of more importance for your business then yes using ADO.NET is better.

Nullable types and ?? operator

kannan.ambadi — Fri, 06 Jun 2008 11:48:00 GMT

This time, i would like to discuss about a cool feature of C# 2.0. As you know, some database operations return null values and results into throwing exceptions unless you handled well in your business logic. .Net 2.0 has been solved by introducing nullable types. Lets discuss about its features and functionalities.
Nullable type can represent all the values of its underlying type, plus the value null. Thus, if you define a nullable boolean, its values comes from either true or false as well as Null.
For, nullable integer can be assigned from integer values and null. We can define a nullable type using its underlying datatype suffixed by a question mark symbol(?). Lets look at the examples

    Examples of nullable types
        //Nullable values must be assigned with an initial value.

        int? intNullable = 2;
        double? dblNullable = 37.73;
        bool? bNullable = true;

        Int[]? arNullable = new int?[1,2];

Keep in mind that nullable types are applicable only to value types or an array of value types.Referance types can't assinged to nullable types, since nullable types instances of System.Nullable(T) struct(here T is the type). If u define a nullable string, it would result into compile-time error!!!!..

Properties and Methods

Nullable type has a property called HasValue, which determines whether the value contains null or not. Nullable types are very useful where you are interacting with databases, especially columns with null or empty values. There is very useful method associated with the Nullable types, GetValueOrDefault() which returns the value of the variable or default value in case of null(for eg: false for bool, 0 for integer, 0.0 for double).

?? Operator

Lets assume, you are accessing a table which has some columns with empty(undefined) values or null values. But still you want to fetch the data since the whole data is very large and time-consuming. Instead of showing those null values, it could be possible to display some predefined values to end user, there by making the data more understanding and readable. This feature can be achieved by using "??" operator. It simply allows you to assign a value to nullable type if the retrieved value is in fact null. The following code-snippet makes this feature more clear.

//Suppose you are executing a database operation

//which returns a null value instead of integer

public Int GetMinimumCount()
{

int? iTemp = ConfigManager.GetMinimumCount() ?? 100;

return iTemp.Value;

}

Nullable types are very useful when we are following ORM architecture(eg: nHibernate), where we would be dealing table fields are class members, so that the chance of getting null values very high compared to 3-Tier architecture. I hope you would get an idea about nullable types and its features.

Exporting Dataset as CSV

kannan.ambadi — Tue, 25 Mar 2008 10:19:00 GMT

Hi Everyone,

Below given an easy way to export data from a dataset as CSV(comma seperated values) . At first, it converts the datatable to html table format and then writes data as output stream. We need to set the Content-Type of Response object as Excel format and add the filename to be streamed on the client browser in a dialog box

Check this snippet

private void ExportToCsvFromDataSet(DataSet dsExport) {

bool IsOutputStreamed = false;

try {

StringBuilder dataToExport = new StringBuilder();

foreach (DataTable dtExport in dsExport.Tables) {

string headerToExport= string.Empty;

foreach (DataColumn dCol in dtExport.Columns)

headerToExport = (char)34 + dCol.ColumnName + (char)34 + (char)44;

headerToExport.Remove(headerToExport.Length - 1, 1);

headerToExport = headerToExport + Environment.NewLine + Environment.NewLine;

dataToExport.Append(headerToExport);

string bodyToExport = string.Empty;

foreach (DataRow dRow in dtExport.Rows) {

foreach (object obj in dRow.ItemArray)

bodyToExport = bodyToExport + obj.ToString() + (char)44;

bodyToExport.Remove(bodyToExport.Length - 1, 1);

bodyToExport = bodyToExport + Environment.NewLine;

}

dataToExport.Append(bodyToExport);

dataToExport.Append(Environment.NewLine);

dataToExport.Append(Environment.NewLine);

if (string.IsNullOrEmpty(dataToExport.ToString())) {

Response.Clear();

Response.ContentType = "Text/vnd.ms-excel";

Response.AddHeader("Content-Disposition", "attachment;filename=report.csv");

Response.Write(dataToExport.ToString());

IsOutputStreamed = true;

}

}

}

catch { }

finally {

if (IsOutputStreamed)

Response.End();

}

}

Download the source code

Simple way to check your code performance

kannan.ambadi — Tue, 25 Mar 2008 08:15:00 GMT

Hi guys,Of course, we all know foreach loop takes more time than for loop and there are lot of similar scenarios in .Net. Even if it takes lot of time, we'll be forced to use foreach loop at some cases. So it'll be better, if we come to know the time taken for executing a piece of code at the runtime. Here is a simple way to find out the time taken for each process.It just writes the start time and finish time taken for the process in the debug window. Debug.Indent() method simply changes the indentation of the Output by one level and Debug.WriteLine() method writes a string in the debug window.

Here is the snippet

//Increases the current IndentLevel

System.Diagnostics.Debug.Indent();

//Writes the starttime

System.Diagnostics.Debug.WriteLine("DEBUG START TIME -> : " + DateTime.Now.ToString("HH:mm s:fff"));

//Execute the code

ConfigureControls();

//Writes the finish time

System.Diagnostics.Debug.WriteLine("DEBUG FINISH TIME -> : " + DateTime.Now.ToString("HH:mm s:fff"));

//Reduces the current IndentLevel

System.Diagnostics.Debug.Unindent();

Hurray!!!!!!

kannan.ambadi — Tue, 25 Mar 2008 08:01:00 GMT

Atlast im in the world of micrsoft blogs..special thanks to joe stagner for providing blog space.

kannan M ambadi