Saving changes is not permitted (SQL Server 2008)

On clean installed SQL Server 2008 instance if you change the Table you may see this message:

This dialog states: "Saving changes is not permitted. The changes you have made require the following tables to be dropped and re-created. You have either made changes to a table that can't be re-created or enabled the option Prevent saving changes that require the table to be re-created."

This can be fixed by changing settings for SQL Server Management Studio.
Open: Tools > Options

Do uncheck "Prevent saving changes that require table re-creation".
Once you do that save will work.

I think Microsoft should made it unchecked by default.

Implementation of thread safe Singleton in C#

Lazy initialization

public sealed class Singleton
{
    static Singleton instance=null;
    static readonly object instancelock = new object();

    Singleton()
    {
    }

    public static Singleton Instance
    {
        get
        {
            lock (instancelock)
            {
                if (instance==null)
                {
                    instance = new Singleton();
                }
                return instance;
            }
        }
    }
}

Thread-safe without locks

public sealed class Singleton
{
    static readonly Singleton instance=new Singleton();

    static Singleton()
    {
    }

    Singleton()
    {
    }

    public static Singleton Instance
    {
        get
        {
            return instance;
        }
    }
}

How to add .NET control to a Win32 window

using System.Runtime.InteropServices;

[DllImport("user32.dll")]
private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

Then when you want attach control on window call

SetParent(control.Handle, parentHWND);
control.BringToFront();

System.Windows.Forms.ComboBox user changes selection event

Recently I found a very exciting thing in System.Windows.Forms.ComboBox that I want to share.

There is a special event for handling selection changes done by user.
If you want to capture user changes do not use SelectedIndexChanged or SelectedValueChanged events, cause those events are also raised when the selection changes programmatically.

SelectionChangeCommitted is raised only when the user changes the combo box selection.

On selection change ComboBox fire event in the following order: ComboBox.ChangeCommitted > ComboBox.ValueChanged > ComboBox.IndexChanged