Delegates Events Ex-1

<form id="form1" runat="server">

        <div>

            <asp:Label ID="lbl" runat="server" Text="Balance Remaining: "></asp:Label>

            <asp:Label ID="lblBalance" runat="server"></asp:Label>

            <br /><br /><br />

             <asp:Label ID="lblmsg" runat="server"></asp:Label>

            <br /><br /><br />

            <asp:Label ID="lbl1" runat="server" Text="Enter Amount to Debit"></asp:Label>

            <asp:TextBox ID="txtDebit" runat="server"></asp:TextBox>

            <br /><br />

            <asp:Label ID="lbl2" runat="server" Text="Enter Amount to Credit"></asp:Label>

            <asp:TextBox ID="txtCredit" runat="server"></asp:TextBox>

            <br /><br /><br />

            <asp:Button ID="btnDebit" runat="server" Text="Debit" OnClick="btnDebit_Click" />

         <asp:Button ID="btnCredit" runat="server" Text="Credit" OnClick="btnCredit_Click" />

        </div>

 </form>

public partial class EventEg : System.Web.UI.Page

{

    BankAccount BA = new BankAccount(); // publisher

    AccountSubscriber sb = new AccountSubscriber();

  

  protected void Page_Load(object sender, EventArgs e)

    {

        lblBalance.Text = BA.Balance.ToString()

    }

  protected void btnDebit_Click(object sender, EventArgs e)

    {

        // MyEventArgs myargs = new MyEventArgs();

        // BA.AccountTransaction += new AccountTransactionEventHandler(sb.AccountTransactionMessageMethod);

        //  BA.AccountTransaction +=  BA. .AccountTransactionMessageMethod(myargs);

        //  BA.AccountTransaction +=  sb.AccountTransactionMessageMethod(this,myargs); 

        BA.AccountTransaction += sb.OnAccountTransactionCompleted;

        BA.Debit(Convert.ToDecimal(txtDebit.Text));

        BA.SetLabelTextBalance(this, lblBalance);

     }

 protected void btnCredit_Click(object sender, EventArgs e)

    {

        //MyEventArgs myargs = new MyEventArgs();

        //BA.Ev_AccountTransaction +=   sb.AccountTransactionMessageMethod(this, myargs);

        BA.AccountTransaction += sb.OnAccountTransactionCompleted;

        BA.Credit(Convert.ToDecimal(txtCredit.Text));

        BA.SetLabelTextBalance(this, lblBalance);

    }

public class AccountSubscriber 

    {

        public void OnAccountTransactionCompleted(object sender,MyEventArgs args)

        {

            HttpContext.Current.Response.Write(args.Message);

            HttpContext.Current.Response.Write(args.MethodRaisingError);

         

            // EventEg eg = new EventEg();

            // Label lb = eg.GetControlFromPageClass() as Label;

            // lb.Text = args.RemainingBalance.ToString();

        }

    }

}  // end of class

BankAccount.cs

namespace DelegatesWebSite

{

    //  create a delegate

    public delegate void AccountTransactionEventHandler(object sender, MyEventArgs args);

  

    public class BankAccount  // publisher class

    {

        private static decimal _balance { get; set; } = 0;

        public decimal Balance

        {

            get

            {

                return _balance;

            }

            private set {

                _balance = value;

            }

        }

        // create an Event of delegate type

        public event AccountTransactionEventHandler AccountTransaction; 

        // public event EventHandler<MyEventArgs> Ev_AccountTransaction;

        protected virtual void OnAccountTransaction(object sender, MyEventArgs a) // this signature should be same as that of the delegate.

        {

            // INVOKE THE EVENT WHEN SOMETHING IS DONE IN THE ACCOUNT

            //if (Ev_AccountTransaction != null)

            //    Ev_AccountTransaction(this, a); // or like below

            AccountTransaction?.Invoke(this, a);

        }

        public void Credit(decimal amount)

        {

            Balance += amount;

            MyEventArgs s = new MyEventArgs();

            s.Message = "Credited Successfully!!";

            s.MethodRaisingError = "Credit Method";

            s.RemainingBalance = Balance;

            OnAccountTransaction(this, s);

        }

       public void Debit(decimal amount)

        {

            if (_balance >= amount)

            {

                _balance -= amount;

                MyEventArgs s = new MyEventArgs();

                s.Message = "Debited Successfully!!";

                s.MethodRaisingError = "Debit Method";

                s.RemainingBalance = Balance;

                OnAccountTransaction(this, s);

            }

            else

            {

                MyEventArgs s = new MyEventArgs();

                s.Message = "Insufficient Funds!!!!";

                s.MethodRaisingError = "Debit Method";

                s.RemainingBalance = Balance;

                OnAccountTransaction(this, s);

            }

        }

        public void SetLabelTextBalance(Page page,Label ctl) {

            ctl = ctl as Label;

            ctl.Text = Balance.ToString();

        }

    }

 

public class MyEventArgs : EventArgs

    {

        public string Message { get; set; }

        public string MethodRaisingError { get; set; }

        public decimal RemainingBalance { get; set; }

        BankAccount ba = new BankAccount();

        public MyEventArgs()

        {

           

        }

        public MyEventArgs(string msg)//: base()

        {

            this.Message = msg;

            this.RemainingBalance = ba.Balance;

        }

    }

}

 

 

Posted in: C#,Delegate,Events