What is the difference of using Invoke and without invoke for invoking delegate references .

Question

Lets consider the below example,
1. Invoke the delegate reference with Invoke keyword,
public delegate double returndel(int r);
 private void button1_Click(object sender, EventArgs e)
            returndel ret = CalculateArea;
            double yt = ret.Invoke(4);   
            MessageBox.Show(yt.ToString());
        public double CalculateArea(int r)
            return 3.14 * r * r;
2.  Invoke the delegate reference without Invoke keyword,
public delegate double returndel(int r);
 private void button1_Click(object sender, EventArgs e)
            returndel ret = new returndel(CalculateArea);
            double yt = ret(4);
            MessageBox.Show(yt.ToString());
 public double CalculateArea(int r)
            return 3.14 * r * r;
What is the difference between these two ?
Thanks and Regards
Bijukrishnan.BS

Answer 1

No difference if you just want to call single function.
Try the following:
public delegate void DoMyWork(int i);
static void DoMyWork1(int i)
Console.WriteLine(i);
static void DoMyWork2(int i)
Console.WriteLine(i * i);
static void delegateTest()
DoMyWork work = new DoMyWork(DoMyWork1);
work += new DoMyWork(DoMyWork2);
work.Invoke(4);
The output would be:
4
16