Setting Menu options Dynamically based on Role in ASP.NET using LINQ

Step 1. Add Menu control to aspx or master page.

<asp:Menu ID=”menuRoleBased” runat=”server” Font-Names=”Verdana” ForeColor=”WhiteSmoke” Orientation=”Horizontal”
                            BorderColor=”#FFCC99″ BorderWidth=”0px” Width=”20%” Font-Bold=”False” Font-Size=”Smaller”>
                            <StaticMenuStyle BorderWidth=”1″ BackColor=”#FFCC99″ BorderColor=”White” BorderStyle=”Solid” />
                            <StaticSelectedStyle Font-Names=”Verdana” BackColor=”#415779″ ForeColor=”white” Height=”25px” />
                            <StaticMenuItemStyle CssClass=”menuHoverStyle” Font-Names=”Verdana” HorizontalPadding=”4px”
                                BorderColor=”White” BorderStyle=”Solid” BorderWidth=”1px” ForeColor=”Black” Height=”25px” />
                            <StaticHoverStyle CssClass=”menuOrangeStyle” Height=”25px” Font-Names=”Verdana” ForeColor=”Black” />
                            <DynamicHoverStyle CssClass=”menuOrangeStyle” Height=”25px” Font-Names=”Verdana”
                                ForeColor=”Black” />
                            <DynamicMenuStyle BorderStyle=”Solid” BorderColor=”white” BorderWidth=”1″ Height=”25px”
                                Font-Names=”Verdana” ForeColor=”White” BackColor=”#FFCC99″ />
                            <DynamicSelectedStyle Height=”25px” Font-Names=”Verdana” ForeColor=”White” BackColor=”#001B36″ />
                            <DynamicMenuItemStyle BorderStyle=”Solid” BorderWidth=”1px” BorderColor=”white” Height=”25px”
                                Font-Names=”Verdana” ForeColor=”white” BackColor=”#FFCC99″ HorizontalPadding=”3px” />
                            <DataBindings>
                                <asp:MenuItemBinding DataMember=”Menu” TextField=”title” ValueField=”description”
                                    NavigateUrlField=”url” />
                                <asp:MenuItemBinding DataMember=”SubMenu” NavigateUrlField=”url” TextField=”title”
                                    ValueField=”description” />
                            </DataBindings>
 </asp:Menu>

Step 2 : Add a xml containing Menu  and Submenu Name , Url and Role. Add a xml file to your project and add below xml content to it.

Xml below has two menus – Request Leave menu for Employee and Approve Leave menu for Manager

<?xml version=”1.0″ encoding=”utf-8″ ?>
<RootMenu>
  <Menu url=”” title=”Request” description=”Request” Role=”Employee” MenuOrder=”0″>
    <SubMenu url=”RequestLeave.aspx”  title=”Request Leave” description=”” />
  </Menu>
  <Menu  url=””  title=”Approve” description=”” Role=”Manager” MenuOrder=”1″>
    <SubMenu url=”ApproveLeave.aspx”  title=”Approve Leave” description=”” />
  </Menu>
 </RootMenu>

Step 3: Write a method to return roles of logged in user. In this example, I will create a GetRole method and populate to set Role array to Employee.

 public String[] GetRole()
    {
        return  new String[]{“Employee”};
    }

Step 4 : Write a method to get Menu xml string dynamically based on role.

public String GetMenu()
    {
        string strMenu = string.Empty;
        string[] loggedUserRole= GetRole();
        DataSet dsMenu = new DataSet();
        string strPath = @”D:MenuMenuRole.xml”;
       
        XDocument xmlDoc = XDocument.Load(strPath);

        List<XElement> roleMenu = new List<XElement>();
        var test = from c in xmlDoc.Descendants(“Menu”)
                   join r in loggedUserRole on c.Attribute(“Role”).Value equals r
                   orderby c.Attribute(“MenuOrder”).Value ascending
                   select c;

        foreach (var p in test)
            strMenu = strMenu + p.ToString();
        strMenu = “<RootMenu>” + strMenu + @”</RootMenu>”;
        return strMenu;
    }

Step 5 : Add xmlDataSource control to aspx or masterpage

<asp:XmlDataSource ID=”srcXMLMPA” runat=”server” XPath=”RootMenu/Menu” EnableCaching=”false”>
    </asp:XmlDataSource>

Step 6 : Add the code to bind dynamically created Role based menu xml string to Menu control

srcXMLMPA.Data = GetMenu();
menuRoleBased.DataSource = srcXMLMPA;
menuRoleBased.DataBind();

Now run the web application to see the result . Since Role array was populated with Employee role therefore only Request Menu will be show . See the result below :

Employee Menu

Now change GetRole method to return Employee and Manager role and run the application to see the difference :

Manager Menu

Aggregate functions in LINQ query

1. Avearage – Returns the average value in sequence

2. Count – Returns count of elements in sequence

3. Max – Returns maximum value in sequence

4. Min – Returns minimum value in sequence

5. Sum – Returns sum of values in sequence

6. Aggregate – Computes custom aggregation in sequence

LINQ to ADO.NET

A .NET application can write LINQ queries to SQL, Entities and Dataset. LINQ to SQL and LINQ to Entities have direct connection with Database through ADO.NET layer.

LINQ to ADO.NET

LINQ to ADO.NET

Anonymous Method , Lambda Expressions and LINQ in C# 3.0

LINQ stands for Language Integrated Query.

List contains flower name below  :

List flowerList = new List();
flowerList.Add(“ROSE”);
flowerList.Add(“VIOLET”);
flowerList.Add(“ORCHID”);

LINQ Lists – Anonymous Delegates

string flowerRose = flowerList.Find(delegate ( string flower ) )
{
return flower = “ROSE”;
}
);

LINQ Lists – Lambda Expressions

string roseFlower = flowerList.Find((string flower ) => flower.Equals(“ROSE”));

LINQ Lists – Linq Query

var flowerR = from string flower in flowerList
                    where flower == “ROSE”
                    select flower;