SilverLight - Fill a ComboBox

Just doing some test

Binding a ComboBox at runtime.

private void button1_Click(object sender, RoutedEventArgs e)

{

List<Car> carList = new List<Car>();

carList.Add(new Car() { Name = "Ferrari", Price = 150000 });

carList.Add(new Car() { Name = "Honda", Price = 12500 });

carList.Add(new Car() { Name = "Toyota", Price = 11500 });

comboBox1.ItemsSource = carList;

comboBox1.DisplayMemberPath = "Name";

comboBox1.SelectedIndex = 2;

comboBox1.SelectionChanged += new SelectionChangedEventHandler(comboBox1_SelectionChanged);

}

void comboBox1_SelectionChanged(object sender, SelectionChangedEventArgs e)

{

Car selCar =(Car) comboBox1.SelectedItem;

MessageBox.Show(selCar.Name);

}

}

public class Car

{

public string Name { get; set; }

public int Price { get; set; }

}

Binding a ComboBox at design time;
<ComboBox Height="23" HorizontalAlignment="Left" Margin="225,184,0,0" Name="comboBox2" VerticalAlignment="Top" Width="120" ItemsSource="{Binding}" >

            <ComboBoxItem Content="Value-1"></ComboBoxItem>

            <ComboBoxItem Content="Value-2"></ComboBoxItem>

            <ComboBoxItem Content="Value-3"></ComboBoxItem>

            <ComboBoxItem Content="Value-4"></ComboBoxItem>

            <ComboBoxItem Content="Value-5"></ComboBoxItem>

</ComboBox>

TripleDES Encryption using MD5 Hashing

Example in VB.Net

Imports System.IO
Imports System.Text
Imports System.Security.Cryptography　
Public NotInheritable Class Utility
 Private Sub New()
End Sub

Private Shared Function CreateDES(ByVal key As String) As TripleDESDim md5 As MD5 = New MD5CryptoServiceProvider()
Dim des As TripleDES = New TripleDESCryptoServiceProvider()
des.Key = md5.ComputeHash(Encoding.Unicode.GetBytes(key))
des.IV = New Byte(des.BlockSize \ 8 - 1) {}
Return des
End Function

Public Shared Function Encryption(ByVal PlainText As String, ByVal key As String) As String
Dim des As TripleDES = CreateDES(key)
Dim ct As ICryptoTransform = des.CreateEncryptor()
Dim input As Byte() = Encoding.Unicode.GetBytes(PlainText)
Return Convert.ToBase64String(ct.TransformFinalBlock(input, 0, input.Length))
End Function

Public Shared Function Decryption(ByVal CypherText As String, ByVal key As String) As String
Dim b As Byte() = Convert.FromBase64String(CypherText)
Dim des As TripleDES = CreateDES(key)
Dim ct As ICryptoTransform = des.CreateDecryptor()
Dim output As Byte() = ct.TransformFinalBlock(b, 0, b.Length)
Return Encoding.Unicode.GetString(output)
End Function

End Class

 Example:
Dim strEncrypted As String = Utility.Encryption("Hello", "TESTKEY3327ABC09876433")
Dim strDecrypted As String = Utility.Decryption(strEncrypted,TESTKEY3327ABC09876433")MessageBox.Show(strDecrypted)

Code Contracts in .NET 4

Reference : http://visualstudiomagazine.com/articles/2010/06/23/code-contracts.aspx
http://www.codeproject.com/KB/cs/CodeContracts.aspx

One of the key features of the .NET Framework is its enforcement of strong typing. But sometimes, simply enforcing that an integer is passed into a method isn't enough. We have to write additional code to make sure the integer is in a particular range or some other requirement. With Code Contracts, we get a language-neutral way to express such additional requirements in the form of preconditions, postconditions and invariants.

What is Code Contracts
Code Contracts is a subset of a larger Microsoft Research Project called Spec# (pronounced "Spec Sharp"). You can read more about this project here. Spec# is a formal language for defining API contracts. A subset of these contracts -- preconditions, postconditions and invariants -- has made its way into Visual Studio 2010 in the form of Code Contracts.

Before being able to utilize Code Contracts, you'll need to download and install it from http://msdn.microsoft.com/en-us/devlabs/dd491992.aspx. Why the need for the download? Code Contracts has support for both Visual Studio 2008 as well as 2010. Since it's not a VS 2010-specific product, a separate download is required.

Example :

using System.Diagnostics.Contracts;

public class TestContract

    {

        int m_n1;

        int m_n2;

        public TestContract(int x,int y)

        {

            Contract.Requires(x > 10, "x should be > 10");

            m_n1 = x;

            m_n2 = y;

        }       

    }

Now try to create an object of TestContract

                TestContract obj = new TestContract(3, 20);

This will throw exception as “x should be > 10”

Parallel Programming with dot net

http://msdn.microsoft.com/en-us/library/ff963553.aspx

Example.
using System.Threading.Tasks;
int n=5;
Parallel.For(0, n, i => {
MessageBox.Show(i.ToString());
});