How to create Menu based on Sitemap and Roles

The following code sample shows how to create Menu based on Sitemap and Roles.

The combination of ASP.NET role management and ASP.NET URL authorization provide
a way to restrict access to Web files based on security roles.

Security trimming is a very cool feature which allows you to hide the urls based
on the users roles.

First create Web.sitemap in website also add roles for access url.

<?xml version="1.0" encoding="utf-8" ?>

<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
<siteMapNode url="~/Default.aspx" title="Home" description="Home">
<siteMapNode url="~/contactus.aspx" title="Contact US" description="Contact US" />
<siteMapNode url="~/aboutus.aspx" title="About Us" description="About Us" roles="*"/>
<siteMapNode url="~/articles.aspx" title="Articles" description="Articles"/>
<siteMapNode url="~/admin.aspx" title="Admin" description="Articles" roles="Admin"/>
</siteMapNode>
</siteMap>

In above site admin.aspx is display only to person who has Admin role.and roles
"*" means display for everyone.

Now,define sitemap providers in web.config file and enable security trimming

(securityTrimmingEnabled is set to true ).


<siteMap defaultProvider="XmlSiteMapProvider" enabled="true">
<providers> <add name="UserMenuSiteMap" description="Used for Menu"
type="System.Web.XmlSiteMapProvider" siteMapFile="Web.siteMap" securityTrimmingEnabled="true"/>
</providers>
</siteMap>

Menu based on Sitemap

For creating menu based on sitemap,Firstly create Web.sitemap (Define Sitemap).Web.Sitemap has Title,Url and description attributes.

<?xml version="1.0" encoding="utf-8" ?>
<siteMap xmlns="http://schemas.microsoft.com/AspNet/SiteMap-File-1.0" >
<siteMapNode url="~/Default.aspx" title="Home" description="Home">
<siteMapNode url="~/contactus.aspx" title="Contact US" description="Contact US"/>
<siteMapNode url="~/aboutus.aspx" title="About Us" description="About Us"/>
<siteMapNode url="~/articles.aspx" title="Articles" description="Articles"/>
</siteMapNode>
</siteMap>

Then,in master page or .aspx drag and drop asp.net control and SiteMapDataSource.And set menu DataSourceID property to SiteMapDataSource.

<asp:Menu ID="Menu1" runat="server" DataSourceID="SiteMapDataSource1" Font-Names="Verdana"
Font-Size="0.8em" ForeColor="#7C6F57" Orientation="Horizontal" StaticSubMenuIndent="10px"
BackColor="#F7F6F3" DynamicHorizontalOffset="2" StaticDisplayLevels="2"></asp:Menu>



<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" />

When you required Horizontal or Vertical menu then just set Orientation property of menu.By default this property set to Vertical.

In code we use DynamicHorizontalOffset property of menu to Gets or sets the number of pixels to shift a dynamic menu horizontally relative to its parent menu item.

In code we use StaticDisplayLevels property of menu to specify the number of menu levels to display in a static menu.

Find Nth highest salary from table

In interview you can faced question like to give solution(query) for find Nth highest salary from given employee table.

TO find out 3rd highest salary from table

--Find 3rd highest salary
SELECT TOP 1 salary
FROM (
SELECT DISTINCT TOP 3 salary
FROM tblSalary
ORDER BY salary DESC) S
ORDER BY salary

General form to find to Nth highest salary from table

--Find Nth highest salary
SELECT TOP 1 salary FROM (
SELECT DISTINCT TOP N salary FROM tblSalary ORDER BY salary DESC) S
ORDER BY salary

There are many solution to solve to this but above solution is easiest.
Take other possible solution,

SELECT MIN(salary) FROM tblSalary WHERE salary IN
(SELECT DISTINCT TOP 3 salary FROM tblSalary ORDER BY salary DESC)

--or--

SELECT MIN(salary) FROM
(SELECT DISTINCT TOP 3 salary FROM tblSalary ORDER BY salary DESC) S

LINQ Introduction

Language Integrated Query (LINQ), a new query language feature in .net 3.5.

You can use it to retrieve data from an array or collection or any data source that supports IEnumerable or IQueryable.

Let's see example how to use LINQ in string array.We have string array of country like this,


Dim countries As String() = {"Australia", "Brazil", "China", "Japan", "India", "United States", "United Kingdom"}
Dim data = From country In countries Where country.StartsWith("Uni") Select country.ToUpper
Response.Write("Country List</br">")
For Each country As String In data
Response.Write(country & "</br">")
Next


Here, you have only change "LINQ Query" with query that discuss below.

==> By using LINQ you can retrive data from array. Below LINQ equivalent to SELECT * statement of SQL Server.

From country In countries Select country

==> You can also use conditional statement in array to get data.To retrive country list that have string length less than 6.

From country In countries Where country.Length < 6 Select country

==> You can also sort an array Ascending/Descending.

From country In countries Order By country Descending Select country

==> To retrive Country name that start with "UNI" and country name in Upper case.

From country In countries Where country.StartsWith("Uni") Select country.ToUpper

Here, I have explain how use LINQ.

Enable/Disable RequiredFieldValidator with Javascript

Sometimes we need to Enable or Disable validation on client side.For that use ValidatorEnable function in the Asp.net javacsript Script Library.

For that set EnableClientScript property of validator to True.

Here i give example for this:

I have a page with a couple of radio buttons.On radio button selection i want to enable/disable validation.

In example if i select Email radio button then Email div will display and only txtEmail textbox validator is enabled.

Java Script for this:

<script language="JavaScript" type="text/javascript">
function autoSelect(control,type)
{
if(type=="Email")
{
document.getElementById('Email').style.display="block";
document.getElementById('PhoneNo').style.display="none";
ValidatorEnable(document.getElementById("RequiredFieldValidator1"), true);
ValidatorEnable(document.getElementById("RequiredFieldValidator2"), false);

}
else
{
document.getElementById('Email').style.display="none";
document.getElementById('PhoneNo').style.display="block";
ValidatorEnable(document.getElementById("RequiredFieldValidator1"), false);
ValidatorEnable(document.getElementById("RequiredFieldValidator2"), true);
}
}
</script>

Code for this:


Email :
<input type="radio" id="RadioButton1" runat="server" value="Plan1" name="Plan" onclick="autoSelect(this,'Email')" checked />
PhoneNo :
<input type="radio" id="RadioButton2" runat="server" value="Plan1" name="Plan" onclick="autoSelect(this,'PhoneNo')" />
<div id="Email">
Email <asp:TextBox ID="txtEmail" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="Email Required"
ControlToValidate="txtEmail" EnableClientScript="true" ValidationGroup="vgSubmit" />
</div>
<div id="PhoneNo" style="display:none">
PhoneNo <asp:TextBox ID="txtPhoneNo" runat="server" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator2" runat="server" ErrorMessage="PhoneNo Required"
ControlToValidate="txtPhoneNo" EnableClientScript="true" ValidationGroup="vgSubmit"/>
</div>
<asp:Button ID="btnSubmit" runat="server" Text="Button" ValidationGroup="vgSubmit"/>

DateTime Formatting in GridView,DetailView,FormView

In Asp.Net 2.0 direct datetime formatting for bound column not possible.

To format column into datatime you have to set HtmlEncode="False" property of BoundField.


The Reason behind for this is bydefault data is Html Encoded that prevents to format date.So, set HtmlEncode to False.

File Download dialog box

Code to open a "save as.." file download dialog box in asp.net 2.
Here,I create a vb.net function for to open file download dialog box.

Use System.IO class for file system. Function argument accepts a File virtual path not physical path.

This code for only .txt file but you also use this code for more extension file.For that change only ContentType.

.htm,.html => "text/HTML"
.txt => "text/plain"
.doc,.rtf => "Application/msword"
.csv,.xls => "Application/x-msexcel"
.pdf =>"Application/pdf"


Function DisplayDownloadDialog(ByVal PathVirtual As String)

Dim strPhysicalPath As String
Dim objFileInfo As System.IO.FileInfo
Try
strPhysicalPath = Server.MapPath(PathVirtual)
'exit if file does not exist
If Not System.IO.File.Exists(strPhysicalPath) _
Then Exit Function
objFileInfo = New System.IO.FileInfo(strPhysicalPath)

Response.Clear()
Response.ClearHeaders()
Response.ClearContent()
'Add Headers to enable dialog display
Response.AddHeader("Content-Disposition", "attachment; filename=" & _
objFileInfo.Name)
Response.AddHeader("Content-Length", objFileInfo.Length.ToString())

Response.ContentType = "Text / plain"

Response.WriteFile(objFileInfo.FullName)


Catch
'on exception take no action
'you can implement differently
Finally

Response.End()

End Try
End Function