DotNet and AJAX

Disable AutoComplete Feature in ASP.NET controls

2011-12-01T11:49:00.000-08:00

a) There is an AutoCompleteType in TextBox Property and it will not disable in FireFox

b) in the TextBox set autocomplete="off"

Works both in IE and FireFox

c) the same above, but add as attribute in code behind
txtDate.Attributes.Add("autocomplete", "off");

Show Friendly Dates in Pages

2011-10-11T08:27:00.000-07:00

Mostly when displaying null dates it appears in the screen as 1/1/0001. To avoid that we can create a readonly property for Example JOINDATESTRING where

public string JoinDateString
{
   get
{
       if (StartDate == DateTime.MinValue)
      {
           return String.Empty();
      }
   else
{
     return StartDate.ToString("dd/MM/yyyy");
    }
}
}

Maintain Scroll Position After Postbacks

2011-09-14T10:06:00.000-07:00

1- In Web.config, in page section declare <pages maintainScrollPositionOnPostBack="true" />, which maintains scroll position for all pages in the site.

2- To set for an individual page, in the page declaration <%@ Page MaintainScrollPositionOnPostback="true" %> or in the codebehind set System.Web.UI.Page.MaintainScrollPositionOnPostBack = true

Formatting GridView

2011-09-01T08:14:00.000-07:00

To Format the values displayed in GridView:
For BOUNDCOLUMN, use the DataFormatString argument

For TEMPLATECOLUMN, use the second argument of Bind() to format data
Eg:

See complete list of formatting:
Source :http://msdn.microsoft.com/en-us/library/system.web.ui.webcontrols.boundfield.dataformatstring.aspx

Format character	Description	Example
C or c	Displays numeric values in currency format. You can specify the number of decimal places.	Format: {0:C} 123.456 -> $123.46 Format: {0:C3} 123.456 -> $123.456
D or d	Displays integer values in decimal format. You can specify the number of digits. (Although the type is referred to as "decimal", the numbers are formatted as integers.)	Format: {0:D} 1234 -> 1234 Format: {0:D6} 1234 -> 001234
E or e	Displays numeric values in scientific (exponential) format. You can specify the number of decimal places.	Format: {0:E} 1052.0329112756 -> 1.052033E+003 Format: {0:E2} -1052.0329112756 -> -1.05e+003
F or f	Displays numeric values in fixed format. You can specify the number of decimal places.	Format: {0:F} 1234.567 -> 1234.57 Format: {0:F3} 1234.567 -> 1234.567
G or g	Displays numeric values in general format (the most compact of either fixed-point or scientific notation). You can specify the number of significant digits.	Format: {0:G} -123.456 -> -123.456 Format: {0:G2} -123.456 -> -120
N or n	Displays numeric values in number format (including group separators and optional negative sign). You can specify the number of decimal places.	Format: {0:N} 1234.567 -> 1,234.57 Format: {0:N4} 1234.567 -> 1,234.5670
P or p	Displays numeric values in percent format. You can specify the number of decimal places.	Format: {0:P} 1 -> 100.00% Format: {0:P1} .5 -> 50.0%
R or r	Displays Single, Double, or BigInteger values in round-trip format.	Format: {0:R} 123456789.12345678 -> 123456789.12345678
X or x	Displays integer values in hexadecimal format. You can specify the number of digits.	Format: {0:X} 255 -> FF Format: {0:x4} 255 -> 00ff

d	Short date pattern.	Format: {0:d} 6/15/2009 1:45:30 PM -> 6/15/2009
D	Long date pattern.	Format: {0:D} 6/15/2009 1:45:30 PM ->Monday, June 15, 2009
f	Full date/time pattern (short time).	Format: {0:f} 6/15/2009 1:45:30 PM -> Monday, June 15, 2009 1:45 PM
F	Full date/time pattern (long time).	Format: {0:F} 6/15/2009 1:45:30 PM -> Monday, June 15, 2009 1:45:30 PM
g	General date/time pattern (short time).	Format: {0:g} 6/15/2009 1:45:30 PM -> 6/15/2009 1:45 PM
G	General date/time pattern (long time).	Format: {0:G} 6/15/2009 1:45:30 PM -> 6/15/2009 1:45:30 PM
M or m	Month/day pattern.	Format: {0:M} 6/15/2009 1:45:30 PM -> June 15
O or o	Round-trip date/time pattern.	Format: {0:o} 6/15/2009 1:45:30 PM -> 2009-06-15T13:45:30.0900000
R or r	RFC1123 pattern (for information, see DateTimeFormatInfo.RFC1123Pattern).	Format: {0:R} 6/15/2009 1:45:30 PM -> Mon, 15 Jun 2009 20:45:30 GMT
s	Sortable date/time pattern.	Format: {0:s} 6/15/2009 1:45:30 PM -> 2009-06-15T13:45:30
t	Short time pattern.	Format: {0:t} 6/15/2009 1:45:30 PM -> 1:45 PM
T	Long time pattern.	Format: {0:T} 6/15/2009 1:45:30 PM -> 1:45:30 PM
u	Universal sortable date/time pattern.	Format: {0:u} 6/15/2009 1:45:30 PM -> 2009-06-15 20:45:30Z
U	Universal full date/time pattern.	Format: {0:U} 6/15/2009 1:45:30 PM -> Monday, June 15, 2009 8:45:30 PM
Y or y	Year month pattern.	Format: {0:Y} 6/15/2009 1:45:30 PM -> June, 2009

How to get Hidden Value in GridView

2011-08-10T08:28:00.000-07:00

Once a column's Visible property is set to Hidden, no longer can we access it, since it returns blank.

To overcome that we can do 4 things
1) Use DATAKEY property and to hidden column ID.
GridView.DataKeys[0].Value.ToString();

2) Use TEMPLATE COLUMN and make it visible and access the values using FindControl.
Label lblID = (Label) GridView.Rows[0].FindControl("lblMyId");

3) Using a sylesheet ,set the property display=none, and can get the values.
GridView.Rows[0].Cell[0].Text

4) After databinding, set the visible property of the column.
GridView.Columns[0].Visible = false;

http://www.dotnetspark.com/kb/1937-how-to-get-hidden-column-value-gridview.aspx

Pages Not Displaying CSS/Themes

2011-08-03T07:10:00.000-07:00

If we enable authentication in web.config, the master page will not display the CSS styles. The reason, one must login to access all folders and files (including styles and pictures).

To overcome this issue, give permission to the folder containing CSS and pictures in the WEB.CONFIG in the location path and authorization in system.web.

GridView RowDataBound or RowCommand

2011-07-27T08:52:00.000-07:00

The best place to check or bind controls can be done in RowDataBind Event of GridView.

It can also be done in RowCommand event handler, but during postback there are chances data be lost. I was attaching javascript to a button with another value collected from a databound control, and during postback the data collected and passed to javascript was lost.

Error annot convert method group 'Identifier' to non-delegate type 'type'. Did you intend to invoke the method?

2011-07-21T07:27:00.000-07:00

This Error occurs when we call a method without parenthesis!!! Like a property

Configuring Visual Source Safe in Visual Studio IDE

2011-07-19T05:27:00.000-07:00

In the Tools -> Options -> Source Control, we should be able to select the Source Control here "Microsoft Visual SourceSafe" or any other provider.

Sometimes the in “Current source control plug-in:”, the only choice available may be “none”. In that case we must manually register the dll.

a) In that case close all Visual Studio instances.

b) Browse to your VSS6\win32 directory and run:
“regsvr32 ssscc.dll”

This would register the library and make VSS 6.0 available in the Visual Studio IDE, when we reopen it.

Using Windows User Role with Active Directory

2011-07-11T12:46:00.000-07:00

To use Active Directory permissions in a ASP.NET web application,

1) In WEB.CONFIG, enable windows authentication
< authentication mode="Windows" / >

2) In IIS, enable Windows Authentication and disable Anonymous authentication

Enter Key Default Submit Button

2011-07-11T05:38:00.000-07:00

If there is only one button in a WEB FORM, pressing ENTER will enable the default submit button.

If there are more than one buttons in a web form, then we can define the default submit thru DEFAULTBUTTON property either in the FORM or with an PANEL.

1<form defaultbutton="btnSubmit" id="form1" runat="server"
</form >

2) <panel defaultutton="btnSubmit" id="pnlFirst" runat="server"></panel>

Connecting MySQL Database with .NET Applications

2011-07-10T11:28:00.000-07:00

We can do this many ways,

1) In the MySQL site there is a library to connect to MySQL.
http://www.mysql.com/products/connector/

Download and install this library. Infact we need only the MySql.Data.dll added as a reference to the project. Then we can work like rest like the ado.net providers with MySQL Connection, MySQLCommand, MySQLDataAdapter and MySQLDataReader

Imports MySql.Data.MySqlClient
Public Sub LoadMySQLDB()

Dim myConnection As MySqlConnection
Dim myDataAdapter As MySqlDataAdapter
Dim myDataSet As DataSet
Dim strSQL As String

myConnection = New MySqlConnection("server=localhost; user id=user1; password=password; database=mydatabase; pooling=false;")

strSQL = "SELECT * FROM mytable;"
myDataAdapter = New MySqlDataAdapter(strSQL, myConnection)
myDataSet = New DataSet()
myDataAdapter.Fill(myDataSet, "mytable")

MySQLDataGrid.DataSource = myDataSet
MySQLDataGrid.DataBind()

End Sub

2) Using OLEDB we can connect to MySQL
3) Using ODBC also we can connect to MySQL.

In GridViewDelete Event KEY values are empty

2011-07-08T12:02:00.000-07:00

In the DELETEROWEVENT, the values returned is empty, it appears that e.Keys and e.Values are only populated if gridview.IsBoundUsingDataSourceID.

A possible resolution

int groupId = (int)GridView1.DataKeys[e.RowIndex].Value;

Building Large-Scale jQuery Applications

2010-12-27T06:54:00.000-08:00

Today we’re going to look at the end-to-end tools and options you have for building large-scale enterprise jQuery applications. Although jQuery is an excellent JavaScript library and provides a well-designed set of tools for development, it’s focus on staying compact and making the DOM easy to use has meant that it doesn’t provide a significant infrastructure for building large-scale apps.

17 Useful Htaccess Tricks and Tips

2010-11-12T06:42:00.000-08:00

17 Useful Htaccess Tricks and Tips

I have collected 17 htaccess methods in this article which I have used or tested it before, and I think some of them are essential tricks and tips to protect your webserver against malicious attacks and other would able to perform simple tasks efficiently such as redirection and web server optimization.

Read it full here

SQL Server: How to insert million numbers to table fast?

2010-10-21T18:20:00.000-07:00

SQL Server: How to insert million numbers to table fast?
The problem is: how to get one million numbers to table with less time? We can solve this problem using different approaches but not all of them are quick. Let’s go now step by step and see how different approaches perform.
Read the full article here

Common Security Mistakes in Web Applications

2010-10-19T11:45:00.000-07:00

Common Security Mistakes in Web Applications
1. Cross-site scripting (XSS)
Cross-site scripting is an attack in which a user is tricked into executing code from an attacker’s site (say evil.com) in the context of our website (let’s call it www.mybiz.com).
2. Cross-site request forgery (CSRF)
CSRF (sometimes abbreviated as XSRF) is an attack where a malicious site tricks our visitors into carrying out an action on our site.
3. Click-jacking

4. SQL injection
In this kind of an attack, the attacker exploits insufficient input validation to gain shell access on your database server
5. Shell injection
Similar to SQL injection, the attacker tries to craft an input string to gain shell access to your web server. Once they have shell access, they could potentially do a lot more. Depending on access privileges, they could add JavaScript to your HTML pages, or gain access to other internal systems on your network
6. Phishing
Phishing is the process where an attacker tricks your users into handing over their login credentials. The attacker may create a page that looks exactly like your login page, and ask the user to log in there by sending them a link via e-mail, IM, Facebook, or something similar.
Click here to read the whole article

The Open Web Application Security Project (OWASP) is a 501c3 not-for-profit worldwide charitable organization focused on improving the security of application software.
http://www.owasp.org/index.php/Main_Page

Importance of Validations in Each Layer

2010-10-05T06:36:00.000-07:00

This is defense in depth. Consider UI input validation the otter most wall. In many ways this is a convenience for the users who are using your application as intended. Validations in the business layer are another wall. Validations in the data access layer are another wall. Validations in the database schema are a final wall. Each wall is important, and each wall should not negate the need to do validations on the next.
Logging failed input validations becomes a critical part of intrusion detection. Seeing that someone attempted a SQL injection attack gives you advance warning that someone is probing your system for vulnerabilities. Logging such details and keeping track of these logs may reassure you that your validations are working. It may also give you an indication of where future attacks may originate from. Every piece of information can be helpful.
Read Full Here

Ten caching mistakes that break your app

2010-10-04T06:19:00.000-07:00

Ten caching mistakes that break your app
By Omar Al Zabir 3 Oct 2010
Here are the top 10 mistakes I have seen:

1.Relying on .NET’s default serializer.
2.Storing large objects in a single cache item.
3.Using cache to share objects between threads.
4.Assuming items will be in cache immediately after storing it.
5.Storing entire collection with nested objects.
6.Storing parent-child objects together and also separately.
7.Caching Configuration settings.
8.Caching Live Objects that has open handle to stream, file, registry, or network.
9.Storing same item using multiple keys.
10.Not updating or deleting items in cache after updating or deleting them on persistent storage.
Let’s see what they are and how to avoid them.
Keep Reading

2010-09-27T06:46:00.000-07:00

Best Practices for ASP.NET MVC
Rate This
ASPNETUE 17 Sep 2010 4:14 PM
[This post is based on a document authored by Ben Grover (a senior developer at Microsoft). It is our intention to integrate this information into the MVC 3 documentation on MSDN. We hope to hear from you and welcome any suggestions you might have.]

This document presents a set of coding guidelines aimed at helping the ASP.NET MVC developer create solid applications. Of course, it's up to you as the developer to decide which of these guidelines are appropriate for your application.

Model Recommendations
The model is where the domain-specific objects are defined. These definitions should include business logic (how objects behave and relate), validation logic (what is a valid value for a given object), data logic (how data objects are persisted) and session logic (tracking user state for the application).
REad here full article

Your Software Can Learn A Lot From ATMs

2010-09-24T07:02:00.000-07:00

So, what can our software learn from an ATM? Well, let's break down the process:
Perform task.
Verify task.
If verification failed, quit and retry.
Read the full article here

NHibernate learning with Screencasts

2009-01-23T18:10:00.000-08:00

Stephen Bohlen, an architect with MicroDesk, has created a series of fifteen screencasts on NHibernate. They amount to a complete course designed to take a developer from novice to advanced intermediate skills in NHibernate. I am very impressed with the series, and I recommend it strongly to any one learning NHibernate.

You can find the screencast series at:http://www.summerofnhibernate.com/[^]

ASP.NET Cheat Sheet

2008-11-27T07:31:00.000-08:00

http://john-sheehan.com/blog/index.php/net-cheat-sheets/

Links for
.NET Format String Quick Reference -Current Version: 1.1
ASP.NET 2.0 Page Life Cycle & Common Events - Current Version: 1.0
Visual Studio 2005 Built-in Code Snippets (C#) - Current Version: 1.0

ASP.NET Page Life Cycle Diagram (PNG)
ASP.NET Runtime Cheat Sheet
Microsoft .NET Framework 3.5 Commonly Uses Types and Namespaces (PDF)
Visual Studio 2005 Default Keybindings C# VB (PDF)
Visual Studio 2008 Default Keybindings C# VB
Microsoft ASP.NET AJAX Library
Microsoft ASP.NET AJAX Client Life Cycle & Events (PDF)
LINQ
VB.NET/C# Comparison
SQL Server
HTML Character Entities
RGB Hex Color Chart
CSS
jQuery
JavaScript
XHTML (PDF)
Regular Expressions
Microformats
ASP/VBScript

Ten Stupid Uses of Windows

2008-07-15T18:56:00.000-07:00

An interesting article on using Windows in critical systems like air traffic control systems,nuclear submarines, etc
http://www.networkworld.com/community/node/29836

Programmer Competency Matrix

2008-07-07T06:01:00.000-07:00

An interesting atricle - Programmer Competency Matrix.
http://www.indiangeek.net/wp-content/uploads/Programmer%20competency%20matrix.htm

Create Membership Database in SQL Server 2005

2007-11-30T09:09:00.000-08:00

aspnet_regsql utility provided under the framework folder helps to install the SQLServer 2005 membership database to use with ASP.NET.

Steps:
1) Navigate to Frameworkfolder
Framework folder is located under %WINDIR%\Microsoft.NET\Framework\v2.0.50727>

2) Run the utility
aspnet_regsql.exe
A GUI interface "ASP.NET SQL Server Setup Wizard" Opens, and follow the instructions which is quite simple. Asks to remove or setup application services and second step to specify the Server and Database .

Find Country Based on IP Address

2007-10-28T10:51:00.000-07:00

I had a requirement to find out Country and set it to a dropdown control. For this I needed to collect the IP of the user and secondly match the IP collected with a database of IP's.

1. Collect the IP of the user. Two IP's are available - one of the proxy's and other the users machines. We must deciede to collect either the proxy IP address or the the machine ip of the user
To collect the IP Address of the Proxy we can use HttpContext.Current.Request.UserHostAddress

To Collect the IP of the user machine(not the proxy server ip),
HttpContext.Current.Request.ServerVariables("HTTP_X_FORWARDED_FOR")

2.Match the collected IP address to an IP Database
As we all know an IP address is in the format xx1.xx2.xx3.xx4.

a)IP Address Table
The IP address table is available as free downloads as text or MS Access DB, contains the following fields:
StartIP,
EndIP,
StartIP as a equivalent number,
EndIP as an equivalent number,
CountryCode and
Country.
If we deciede to keep this table as a table in our database, it needs to be a different table (not to integrate with existing country table), since there are many IP address rows per country.

b) Convert IP Address to its Equivalent Number
We have to convert the collected IP to its equivalent number. The following formulae will convert to its equivalent number - (xx1*16777216) +(xx2*65536)+(xx3*256) +xx4

c) Match the equivalent number of converted IP to that of the IP Database
Match the following formulae to get its equivalent country.

If lngConvertedIP between NumberEquivalentOfStartIP and NumberEquivalentOfEndIP, retrieve countryCode.

Custom Format in Datagrid - Multiple Rows and Columns

2007-10-24T17:45:00.000-07:00

I needed to display data in Datagrid with a custom format - 3 rows X 4 Column instead of the default single row.

It was done by first adding layouts in a webuser control. Webuser control helps to make maintenance easy, playing in the templates of datagrid. Added the webuser control into the datagrid in a template column. Then bind the data. Let me elaborate it.

1. Add a UserControl and create its layout:

a) Design the layout - I made a three row, 3 column table table and placed label control in the cells.

b)Assign Values to the Controls - I had used labels to display data and used Databinder.Eval to display it in the Text property
< id="lblCountry" runat="server" text="'< %#">'> < /asp:Label >

2. Create DataGrid in the webform and add webusercontrol to the datagrid
So the Webusergrid is done, and created a datagrid in the Webform. In the datagrid, created a template column with autogenerate columns as false. The following is the markup
< id="dbgSearch" runat="server" autogeneratecolumns="False">
<><>< id="MyProvider1" runat="server">< /itemtemplate >< /asp:TemplateColumn >< /columns >
< /asp:DataGrid >
3. Binding Data to the Datagrid
And in the code of webform ( .aspx.vb), done the following code to bind the data

dbgSearch.DataSource = FillCountries
dbgSearch.DataBind()

Note: The datafield passed from to the datasource must match the property defined in the webusercontrols property.

Start and Stop SQLServer 2005 from Command Prompt

2007-10-21T10:52:00.000-07:00

Why always spend time opening services and from Control Panel to start or stop SQL Server. It can be done thru command prompt

To Start SQL Server at the command prompt (Start->Run)
net start MSSQLSERVER

To Stop SQL Server from the command prompt (Start->Run)
net stop MSSQLSERVER

Dropdownlist - Binding Values, and setting a Value

2007-10-20T18:26:00.000-07:00

1. To Bind Data to a DropDownList,
Data can be binded to a dropdownlist from , Arraylist or objectdatasource, and DataSource property can be used.

DropDownList1.Datasource=
DropDownList1.DataTextField= "UserName"
DropDownList1.DataValueField="UserID"
DropDownList1.DataBind()

2. To set values to a dropdown list from code, we have to use SelectedValue property of dropdown control

Dim strUserName as string ="Bill"
DropDownList1.SelectedValue=
DropDownList1.Items.IndexOf(DropDownList1.Items.FindByValue(strUserName))

AJAX Accordian Control - Object reference not set to an instance of an object

2007-10-20T09:29:00.001-07:00

I was getting the error message for all the Standard Controls available in the Toolbar.

Object reference not set to an instance of an object.

Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

I was wondering why and I found a neat and straight workaround in the following link http://couldbedone.blogspot.com/2007/07/what-wrong-with-accordion-control.html

This workaround worked for me well, by adding

Accordion1.FindControl("nothing")

in page_init handler