1 : Introducing C#
What is C#?
------------------------------------------
C#('C Sharp') is a simple, modern, general-purpose, object-oriented programming language developed by Microsoft.
It has been designed to support the key feature of .Net Framwork.
It is a simple efficent, productive and type-safe language.
It is a purely objected-oriented, modern language suitable for developing Web based application.
Features of C#
------------------------------------------
It has numerous strong programming features that make it endearing to a number of programmers worldwide.
The important features of C# as follows −- Automatic Garbage Collection
- Versioning support
- Strict type-safety
- Delegates and Events
- Boxing and Unboxing
- Web Services
- Properties to access data members.
- Boolean Conditions
- Standard Library
- Assembly Versioning
- Properties and Events
- Easy-to-use Generics
- Indexers
- Conditional Compilation
- Simple Multithreading
- LINQ and Lambda Expressions
- Integration with Windows
Characteristics of C#
------------------------------------------C# is designed for both computing and communications. The key feature are as followes : - Simple
- Consistent
- Modern
- Object-oriented
- Type-safe
- Versionable
- Compatible
- Interoperable and
- Flexible
The below code swaps two given values of variables without using the third variable in C#.
<!DOCTYPE html>
<head></head>
<body>
<form>
<div>
<h3>Swap Value of Two Variable Without Using 3rd Variable</h3>
<p><u>Value before swaping </u></p>
Value of A :<asp:Label ID="lblA" runat="server"></asp:Label><br />
Value of B :<asp:Label ID="lblB" runat="server"></asp:Label><br />
<p><u>Value after swaping </u></p>
Value of A :<asp:Label ID="lblAS" runat="server"></asp:Label><br />
Value of B :<asp:Label ID="lblBS" runat="server"></asp:Label><br />
</div>
</form>
</body>
</html>
C# Code for swapping value of variable :
protected void Page_Load(object sender, EventArgs e)
{
int a = 10, b=20;
lblA.Text = a.ToString();
lblB.Text = b.ToString();
a = a + b;
b = a - b;
a = a - b;
lblAS.Text = a.ToString();
lblBS.Text = b.ToString();
}
How to use if... else condition to show/hide text in HTML?
Here i want to Show/Hide the text in HTML page as per condition OR as per rights.
This depends on the exact details / condition that we want to use to determine if something should be displayed or not.
For example, you could use the User.Identity.IsAuthenticated property to determine if a login user has rights to see this:
<!-- Conditionally display Show or Hide -->
<% if(User.Identity.IsAuthenticated){ %>
<b>Show</b>
<% } else { %>
<b>Hide</b>
<% } %>
And you also apply this in the <ul><li></li></ul> only if condition:
<ul>
<li><a href="#">Home</a></li>
<% if (User.Identity.IsAuthenticated){ %>
<li><a href="#">Dashboard</a></li>
<% } %>
</ul>
Here i am going to populate statically DataTextField and DataValueField in DropDownList using c#.ddlName.Items.Insert(0, new ListItem("-- Select --", "0"));
Note : In above, there is
first zero stands for position of ListItem and
second zero is DataValue of the ListItem and
"-- Select --" is the DataText for visible in DropDown.
Add Asp:DropDownList Control to the page like: <tr>
<td><b>Name</b></td>
<td><asp:DropDownList ID="ddlName" runat="server"</asp:DropDownList></td>
</tr>
Add C# code to bind the Name to the DropdownList as below :
private void BindNames()
{
ddlName.Items.Insert(0, new ListItem("-- Select Name --", "0"));
ddlName.Items.Insert(1, new ListItem("Ajay Gangwar", "1"));
ddlName.Items.Insert(2, new ListItem("Shashank Tripathi", "2"));
ddlName.Items.Insert(3, new ListItem("Heena Nautiyal", "3"));
}
Note : Do not forget to call this method on Page_Load().protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindNames();
}
}