Runtime Assign Method using Delegate

Writing Plug-in Methods with Delegates




A delegate variable is assigned a method dynamically. This is useful for writing plug-
in methods. In this example, we have a utility method named  Add,Sub that applies
a NumberOper . The NumberOper method has a delegate
parameter,

   ///

        /// delegate  declaration

        ///

        ///

        ///

        ///

        public delegate int NumberOperation(int fvalue, int svalue);

        ///

        /// Button click event it will call NumberOper method

        ///

        ///

        ///

        private void btnClick_Click(object sender, EventArgs e)

        {

            int a = Convert.ToInt16(txtfvalue.Text);

            int b = Convert.ToInt16(txtsvalue.Text);

            txtresult.Text = NumberOper(a, b, Add).ToString();//Dynamic we Assign Method name

        }

        ///

        /// Button click event it will call NumberOper method

        ///

        ///

        ///

        private void btnSub_Click(object sender, EventArgs e)

        {

            int a = Convert.ToInt16(txtfvalue.Text);

            int b = Convert.ToInt16(txtsvalue.Text);

            txtresult.Text = NumberOper(a, b, Sub).ToString(); //Dynamic we Assign Method name

        }

        ///

        /// Main Method with delegate Parameter

        ///

        /// first value

        /// second value

        /// Dynamic Delegate

        /// call method add or sub and return result

        public int NumberOper(int a, int b, NumberOperation AT)

        {

          return   AT(a, b);

        }

        ///

        /// Add two numbers Methos

        ///

        /// first Value

        /// Second value

        /// Result

        public int Add(int a, int b)

        {

            return a + b;

        }

        ///

        /// Sub two number

        ///

        /// first value

        /// Second value

        /// int value

        public int Sub(int a, int b)

        {

            return a - b;

        }