Lambda Simplified

Introduction

Lambda expressions in C# are simple to use, but when you see Lambda expression for the first time, it will be so confusing. The article simplifies the understanding of a Lambda expression by taking you through a code evolution tour.

Evolution

In a typical .NET 1.0 code, the simple event handler can be written as follows:

public Form1()
{
   InitializeComponent();
   this.button1.Click += new System.EventHandler(this.button1_Click);
}

private void button1_Click(object sender, EventArgs e)
{
   MessageBox.Show("Hello Events");
}

By using .NET 2.0 Anonymous method, we can simplify the code by:

• Removing method name
• Bringing it closer to event handler (move the code within the {})
• No need to add Event Handler. You can use Delegate keyword to create a delegate object of the anonymous method.

public Form1()
{
   InitializeComponent();
   this.button1.Click += new System.EventHandler(this.button1_Click);

    private void button1_Click delegate (object sender, EventArgs e)
    {
        MessageBox.Show("Hello Events");
    }
}

So if you use anonymous method, the code looks like:

public Form1()
{
   InitializeComponent();
   this.button1.Click += delegate (object sender, EventArgs e)
                         {
                             MessageBox.Show("Hello Events");
                         };
}

By using .NET 3.0 lambda syntax, the code is even more simplified.

• You can remove delegate keyword
• No need to explicitly state the param types, as the compiler can inference type types
• When we have single expression, no need for {} also.
• and introduce => to split the param and method expression.

public Form1()
{
   InitializeComponent();
   this.button1.Click += delegate (object sender, EventArgs e) =>
                         {
                             MessageBox.Show("Hello Events");
                         };
}

So now with Lambda syntax, the same code simplified as below:

public Form1()
{
   InitializeComponent();
   this.button1.Click += (sender, e) => MessageBox.Show("Hello Events");
 }

Conclusion

The article try to simplify the understanding of Lambda expression. To know more about Lambda, check this MSDN article.

This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)