DOT NET – How to make a button as default button and set Focus on a particular text box

In the initial days when i was new to development side and in some site i used to login straight away when i enter username and password and hit Enter key on my keyboard.

I used to think how is this happening but never had any answer but now i am going to show how thats possible.

In this post I will be talking about how  to make any button Default button and set Focus on a particular text box in any page thats displayed.

Ex: Make a test site and go to default.aspx

Step 1:

in <body> tag write the following code

<body>

<form id=”frmExample” runat=”server” defaultbutton=”btnLogin” defaultfocus=”txtUserName”>

<table><tr><td width=”50%”>

Welcome to the Example Web site from dilip

</td>

<td width=”50%”>

<table>

<tr><td><asp:TextBox ID=”txtUserName” runat=”server” Text=”UserName” /></td><td><asp:TextBox ID=”txtPassword” runat=”server” Text=”Password”/></td></tr>

<tr><td><asp:Button ID=”btnLogin” runat=”server” Text=”Login” onclick=”btnLogin_Click”/></td><td><asp:Button ID=”btnSignIn” runat=”server” Text=”Signup”/></td></tr>

</table>

</td>

</tr>

</table>

</form>

</body>

Note: Here the beauty is that i have login and singnup button and i made defaultbutton as login button, and defaultfocus on username text box so whenever this page is viewed from any web browser focus will be on username text box and default button will be login button so when u hit enter it will invoke login button so simple.

 Step 2: see  carefully i have a function onclick=”btnLogin_Click” now press F7 key and go to .cs side of the same page or right click on the mouse and select view code .

and write the following code in .cs side

protected void btnLogin_Click(object sender, EventArgs e)

{

Response.Write(“Default Button was clicked and u are now logged In”);

Response.End();

}

Note: Here another concept when ever you enter key this method will be invoked and at the same time there wont be any other you can see that means response is closed just to make you feel that you really logged in but actually u are in same page.

the output is some this like this :

First Time when visited:

you can see username text box is in focus.

Then when enter key is pressed:

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )

DOT NET – Difference between string and string builder

In Dot Net there will be many cases where in we need to operate on strings and first thing we remember is using system.String but there are certainly many points we need to remember and consider before we operate on strings.

1) Performance.

2)how many times we need to concatenate.

Lets take an example for concatenate five strings.

EX 1. Using System.String

System.String str =“My Name is dilip”;

str += “and i am”; str += “working on “;

str += “Post of “;

str += “difference between string and string builder”;

Response.Write(str);

and the expected output well you probably guessed it right

“My Name is dilipand i amworking on Post of difference between string and string builder”

Now what has happed? yes the important question now how many times we have appended the str variable those number of times string was created in memory location and abandoned when a new string is created and later waiting for garbage collection.

This leads to memory wastage and degradation of performance because string are immutable(that means any change to string causes a runtime to create a new string and abandon old one).

Think about the situation where in u need to work on 100 or more strings????

Dot Net has answer for it in the form of System.Text.StringBuilder class

EX2. Same Example using StringBuilder

StringBuilder sb = new StringBuilder();

sb.Append( “My Name is dilip”);

sb.Append( “and i am”);

sb.Append( “working on “);

sb.Append( “Post of “);

sb.Append( “difference between string and string builder”);

and the output is same as previous

“My Name is dilipand i amworking on Post of difference between string and string builder”

But this time there was only one string created in memory dynamically and modified as we append the new string, by this there is not much garbage collection and also helps improve performance. Append is taken only for example there are a lot of other functions which are just waiting for you to invoke.Happy coding.

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )

DOT NET – Maintaining user information for Security & other requirements

– Create login.aspx in the root directory and design the page according to requirement. Code for this should be written after completing preperation of Entities, DL, BL and others…..

– Goto DB that the project is configured and create tables for storing user information. In general userinformation will have multiple tables, many columns but in our example
we will create users table with username(pk),password,role.

– Add some sample data in the created table and optionally write procedures for accessing the created tables.[In real time highly recommended is access tables with procedures]

– Once db is prepared we have to prepare front-end layers and as usual we will use EDM(O-R) for preparing our objects. prepare edm objects.

– once EDM objects are prepared we have create BL for users where we have to provide all functionality.
……………………..

– Now we can write code for login button of login page. In this button we have to pass userdetails to bl and on successfull evaluation i.e when it returns true we must create forms identity.

class prjuser
{
string _uname,_password;

public
….
….

….
}

c1 obj=new c1();
obj.a=10

class c2 : c1

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )

JQuery Accordion

Accordion Functionality can be achieved by many ways one of the way is using jquery.

Name the above file as accordion.html and in the same folder jquery.js file.

you can download same for free from here.

and then have your custom according just waiting for you to use.

the output looks like this :

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )

DOT NET – What is a cookie

Recently I got a message from one of the reader of my site that what exactly is a cookie. So I decided to wire a post dedicated to it .

  1. A cookie is name=value pair like variable which is stored as a file(persistant cookie) and which travels automatically between every request and response.
  2. Cookies are based on domains(website). As long as user is working with current web site cookie will be available.
  3. Cookies are maintained by browser but not by server which means cookies based websites are dependent on client.
  4. Cookies can be created as
    (i) In-memory cookie
    (ii) Persistant Cookie

An In-memory cookie means as long as user is working with app it will be available – also called as Session Cookie.

Persistant cookie means it will be stored in client physical location and available online as well as offline.

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )

DOT NET 4.0 – Concerns and criticisms relating to .NET

Here are most known Criticisms

  • Applications running in a managed environment such as the Microsoft framework’s CLR or Java’s JVM tend to require more system resources than similar applications that access machine resources more directly. Some applications, however, have been shown to perform better in .NET than in their native version. This could be due to the runtime optimizations made possible by such an environment, the use of relatively well-performing functions in the .NET framework, just-in-time compilation of managed code, or other aspects of the CLR.

 

  • As JIT languages can be more easily reverse-engineered than native code to algorithms used by an application there is concern over possible loss of trade secrets and the bypassing of license control mechanisms. Many obfuscation techniques already developed, however, can help to prevent this; indeed Microsoft’s Visual Studio 2005 includes such a tool.

 

  • In a managed environment such as the Microsoft framework’s CLR or Java’s JVM the regularly occurring garbage collection for reclaiming memory suspends execution of the application for an unpredictable lapse of time (typically no more than a few milliseconds).

 

  • Since the framework is not pre-installed on older versions of Windows an application that requires it must verify that it is present, and if it is not, guide the user to install it.

 

  • Newer versions of the framework (3.5 and up) are not pre-installed on any versions of the Windows operating system. Some developers have expressed concerns about the large size (around 54 MB for end-users with .NET 3.0 and 65 MB with .NET 3.5).

Reference : Dilip Kumar Jena ( https://mstechexplore.wordpress.com )