Re: Changed class

I'm trying to build a class that can track changes to itself.

Class MyClass
{
public int value1=0;
public int value2=0;
private int oldvalue1=0;
private int oldvalue2=0;
public void WhatIsChanged()
{
if(oldvalue1!=value1) Console.WriteLine("value1 is changed");
if(oldvalue2!=value2) Console.WriteLine("value2 is changed");
oldvalue1=value1;
oldvalue2=value2;
}
}
class myprogram
{
MyClass nn = new MyClass()
nn.value1=2;
nn.WhatIsChanged();
}
But there MUST be a simpler way of doing this?

So if I use MemberwiseClone(); will it be like?
Class MyClass
{
public int value1=0;
public int value2=0;
private oldvalues=null;
MyClass()
{
oldvalues=(MyClass)this.MemberwiseClone();
}
public void WhatIsChanged()
{
if(oldvalues.value1!=this.value1) Console.WriteLine("value1 is
changed");
if(oldvalues.value2!=this.value2) Console.WriteLine("value2 is
changed");
oldvalues=(MyClass)this.MemberwiseClone();
}
}
class myprogram
{
MyClass nn = new MyClass()
nn.value1=2;
nn.WhatIsChanged();
}
But this don't work!


I would opt for more of a observer (.NET style) type of pattern. And let another object be responsible for tracking changes.

public class Class1
{
	/// <summary>
	/// The main entry point for the application.
	/// </summary>
	[STAThread]
	private static void Main()
	{
		new Class1();
	}

	public Class1()
	{
		MyClass original = new MyClass(5, 2);
		original.Value1Changed += new MyClass.IntegerChangedHandler(original_Value1Changed);
		original.Value2Changed += new MyClass.IntegerChangedHandler(original_Value2Changed);

		original.Value1 = 32;
		original.Value2 = 1024;
		
		original.Value1 = 5;
		original.Value2 = 2;

		Console.ReadLine();
	}

	private void original_Value1Changed(int oldValue, int newValue)
	{
		Console.WriteLine("Value1 has changed from {0} to {1}.", oldValue, newValue);
	}

	private void original_Value2Changed(int oldValue, int newValue)
	{
		Console.WriteLine("Value2 has changed from {0} to {1}.", oldValue, newValue);
	}
}

public class MyClass
{
	public delegate void IntegerChangedHandler(int oldValue, int newValue);
	
	public event IntegerChangedHandler Value1Changed;
	public event IntegerChangedHandler Value2Changed;
	
	private int value1;
	private int value2;

	public MyClass()
	{}

	public MyClass(int value1, int value2)
	{
		this.value1 = value1;
		this.value2 = value2;
	}


	public int Value1
	{
		get { return value1; }
		set
		{
			OnValue1Changed(value1, value);

			value1 = value;
		}
	}

	public int Value2
	{
		get { return value2; }
		set
		{
			OnValue2Changed(value2, value);

			value2 = value;
		}
	}

	protected virtual void OnValue1Changed(int oldValue, int newValue)
	{
		IntegerChangedHandler handler = Value1Changed;

		if (handler != null)
		{
			handler(oldValue, newValue);
		}
	}

	protected virtual void OnValue2Changed(int oldValue, int newValue)
	{
		IntegerChangedHandler handler = Value2Changed;

		if (handler != null)
		{
			handler(oldValue, newValue);
		}
	}
}


.

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