如何使用WPF应用程序向列表框条目添加ID以删除条目以及在列表中记录

Question

I am trying to make a customer details system for uni that stores a customers name, email, telephone number, skype, etc.

I have it all set up so that you can add, delete, and find there details in the list. The list only stays in memory while the program runs. I have an extra advanced task where I have to add the customers details entered to the list to a listbox. It should show their ID number which they have automatically assigned and their name. When you click on it, it is supposed to show their full details list on the app.

The problem I am having is that when I add an entry to the listbox, it doesn't really have any kind of ID that I can use to search the list for that person I have had to set up taking the name of the listbox entry, turning it into a string and cutting off the name part, leaving the ID. doing this I can delete the entry at the same time as the actual list record. But I also have an ID textbox that when you enter the ID of a person and click the delete button, it deletes the list record, but not the listbox entry. How do I get it to delete the entry as well when it is not currently selected?

I also have a problem where if I add two people and try to search for the first person. it says their ID does not exist? It also only shows the last person entered details when you click on the first listbox entry.

Here is the WPF:

Here is my code for the buttons and textboxes:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using BusinessObjects;

namespace Demo
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        //Object to hold details for each customer.
        Customer cust = new Customer();
        //List to hold details of each customer.
        private MailingList store = new MailingList();
        //Variable to set starting ID number.
        private int ID = 10001;

        public MainWindow()
        {
            InitializeComponent();
        }

        // Button for Adding a customer with a specific assigned ID number.
        private void btnAdd_Click(object sender, RoutedEventArgs e)
        {
            try
            {
                // If statements that catches errors within textboxes
                if (txtFName.Text == "" || txtFName.Text.Length > 15 || Regex.IsMatch(txtFName.Text, @"^[0-9]+$"))
                {
                    throw new Exception();
                }
                else if (txtSName.Text == "" || txtSName.Text.Length > 25 || Regex.IsMatch(txtSName.Text, @"^[0-9]+$"))
                {
                    throw new Exception();
                }
                else if (txtEmail.Text == "" || !Regex.IsMatch(txtEmail.Text, @"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
                @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-0-9a-z]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$"))
                {
                    throw new Exception();
                }
                else if (txtSkype.Text == "" || txtSkype.Text.Length > 32)
                {
                    throw new Exception();
                }
                else if (txtTelephone.Text == "" || txtTelephone.Text.Length > 11 || Regex.IsMatch(txtTelephone.Text, @"^[a-zA-Z]+$"))
                {
                    throw new Exception();
                }
                else if (txtPrefContact.Text == "" || !Regex.IsMatch(txtPrefContact.Text, @"^(?:tel|email|skype)+$"))
                {
                    throw new Exception();
                }

                // Stores the details of the textboxes into the customer details for each list entry.
                cust.ID = ID;
                cust.FirstName = txtFName.Text;
                cust.SecondName = txtSName.Text;
                cust.Email = txtEmail.Text;
                cust.SkypeID = txtSkype.Text;
                cust.Telephone = txtTelephone.Text;
                cust.PrefContact = txtPrefContact.Text;

                // Adds the details of the person above to the list and increases the ID number by one for the next entry.
                store.add(cust);
                ID++;

                lbxCustomers.Items.Add(cust.ID + " " +cust.FirstName + " " + cust.SecondName);

                // Shows user the details of the person added to the list.
                MessageBox.Show("Name: " + cust.FirstName + " " + cust.SecondName +
                              "\nEmail: " + cust.Email +
                              "\nSkype: " + cust.SkypeID +
                              "\nTelephone: " + cust.Telephone +
                              "\nPreferred Contact: " + cust.PrefContact +
                              "\nID No: " + cust.ID);

                // Clears all textboxes for next entry after adding a customer.
                txtFName.Clear();
                txtSName.Clear();
                txtEmail.Clear();
                txtSkype.Clear();
                txtTelephone.Clear();
                txtPrefContact.Clear();
            }
            catch
            {
                // IF statements that displays errors after catching them
                if (txtFName.Text == "" || txtFName.Text.Length > 15 || Regex.IsMatch(txtFName.Text, @"^[0-9]+$"))
                {
                    MessageBox.Show("You must enter a first name within 15 characters." +
                                  "\nNo numbers allowed.");
                    // Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }
                else if (txtSName.Text == "" || txtSName.Text.Length > 15 || Regex.IsMatch(txtSName.Text, @"^[0-9]+$"))
                {
                    MessageBox.Show("You must enter a second name within 25 characters." +
                                  "\nNo numbers allowed.");
                    //Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }
                else if (txtEmail.Text == "" || !Regex.IsMatch(txtEmail.Text, @"^(?("")("".+?(?<!\\)""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" +
                @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-0-9a-z]*[0-9a-z]*\.)+[a-z0-9][\-a-z0-9]{0,22}[a-z0-9]))$"))
                {
                    MessageBox.Show("You haven't entered a valid email address.");
                    // Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }
                else if (txtSkype.Text == "" || txtSkype.Text.Length > 32)
                {
                    MessageBox.Show("You haven't entered a valid Skype address." +
                                  "\nMust be within 32 letters and numbers.");
                    // Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }
                else if (txtTelephone.Text == "" || txtTelephone.Text.Length > 11 || Regex.IsMatch(txtTelephone.Text, @"^[a-zA-Z]+$"))
                {
                    MessageBox.Show("You must enter an 11 digit phone number." +
                                  "\nNo Letters allowed.");
                    // Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }                
                else if (txtPrefContact.Text == "" || !Regex.IsMatch(txtPrefContact.Text, @"^(?:tel|email|skype)+$"))
                {
                    MessageBox.Show("You have not entered the correct preferred contact." +
                                  "\nPlease enter either email, skype or tel.");
                    // Clears all textboxes for next entry after throwing exception.
                    txtFName.Clear();
                    txtSName.Clear();
                    txtEmail.Clear();
                    txtSkype.Clear();
                    txtTelephone.Clear();
                    txtPrefContact.Clear();
                    return;
                }
            }
        }

        // Button for deleting a specific customer with their specific ID.
        private void btnDelete_Click(object sender, RoutedEventArgs e)
        {
            // Makes sure the selected listbox entry is not negative.
            if (lbxCustomers.SelectedIndex >= 0)
            {
                // Get the currently selected item in the ListBox, convert it to a string and then cut off the name leaving only the id number.
                string curItem = lbxCustomers.SelectedItem.ToString();
                string result1 = curItem.Remove(6, curItem.Length - 6);

                // Allows the text from result 1 to be converted back to an integer to use for locating customer.
                int ID = Int32.Parse(result1);

                // Deletes the selected listbox entry and deletes that person from the list.
                lbxCustomers.Items.RemoveAt(lbxCustomers.SelectedIndex);
                store.delete(ID);

                // Stops from continuing on to check if an ID is in the ID textbox.
                return;
            }

            try
            {
                // Allows the text in the ID textbox to be changed to an integer to be used for checking the ID.
                int id = Int32.Parse(txtID.Text);

                /*If the ID number entered is not found in the list, 
                an error message is displayed to say the customer does not exist.
                If the ID does exist, deletes that customer. */

                if (store.find(id) == null)
                {
                    // Displays error message to tell user that this customer does not exist.
                    MessageBox.Show("Invalid ID!" +
                                  "\nNo Customer with this ID exists!");
                }
                else
                {
                    lbxCustomers.Items.Remove(store.ids);

                    // Displays the details of customer with specific ID.
                    store.delete(id);

                    // Displays the details of the customer deleted
                    MessageBox.Show("Deleted Customer:" +
                                  "\nName: " + cust.FirstName + " " + cust.SecondName +
                                  "\nEmail: " + cust.Email +
                                  "\nSkype: " + cust.SkypeID +
                                  "\nTelephone: " + cust.Telephone +
                                  "\nPreferred Contact: " + cust.PrefContact +
                                  "\nID No: " + cust.ID);
                }
            }
            catch
            {
                MessageBox.Show("You did not enter a correct ID!");
                return;
            }
        }

        // Button for Finding a specific customer with their specific ID.
        private void btnFind_Click(object sender, RoutedEventArgs e)
        {
            // Checking for error
            try
            {
                // Allows the text in the ID textbox to be changed to an integer to be used for checking the ID.
                int id = Int32.Parse(txtID.Text);

                /*If the ID number entered is not found in the list, 
                an error message is displayed to say the user does not exist.
                If the ID does exist, shows the user the details of the person with that ID. */
                if (store.find(id) == null)
                {
                    // Displays error message to tell user that this customer does not exist.
                    MessageBox.Show("Invalid ID!" +
                                    "\nNo Customer with this ID exists!");
                }
                else
                {
                    // Displays the details of customer with specific ID.
                    MessageBox.Show(store.Display(id));
                }
            }
            catch
            {
                MessageBox.Show("You did not enter a correct ID!");
            }
        }

        private void lbxCustomers_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            // Allows user to delete a listbox entry without program crashing whilst still having one selected to show details.
            try
            {
                // Get the currently selected item in the ListBox, convert it to a string and then cut off the name leaving only the id number.
                string curItem = lbxCustomers.SelectedItem.ToString();
                string result1 = curItem.Remove(6, curItem.Length - 6);

                // Allows the text from result 1 to be converted back to an integer to use for locating customer.
                int ID = Int32.Parse(result1);

                // Shows the user the selected customers full details.
                MessageBox.Show(cust.Display(ID));
            }
            catch
            {
            }
        }
    }
}

This is my customer class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace BusinessObjects
{
    public class Customer
    {
        //Variables to hold each specific detail for each customer for adding to the list.
        private int _customerID;
        private string _telephone;
        private string _firstName;
        private string _secondName;
        private string _email;
        private string _skypeID;
        private string _prefContact;

        //Get/Set for using ID value.
        public int ID
        {
            get
            {
                return _customerID;
            }
            set
            {
                _customerID = value;
            }
        }

        //Get/Set for using First Name value.
        public string FirstName
        {
            get
            {
                return _firstName;
            }
            set
            {
                _firstName = value;
            }
        }

        //Get/Set for using Second Name value.
        public string SecondName
        {
            get
            {
                return _secondName;
            }
            set
            {
                _secondName = value;
            }
        }

        //Get/Set for using Skype value.
        public string SkypeID
        {
            get
            {
                return _skypeID;
            }
            set
            {
                _skypeID = value;
            }
        }

        //Get/Set for using Telephone value.
        public string Telephone
        {
            get
            {
                return _telephone;
            }
            set
            {
                _telephone = value;
            }
        }

        //Get/Set for using Email value.
        public string Email
        {
            get
            {
                return _email;
            }
            set
            {
                _email = value;
            }
        }

        //Get/Set for using preferred Contact value.
        public string PrefContact
        {
            get
            {
                return _prefContact;
            }
            set
            {
                _prefContact = value;
            }
        }

        public string PrintDetails()
        {
            return "Found:" +
                 "\nName: " + FirstName + " " + SecondName +
                 "\nEmail: " + Email +
                 "\nSkype: " + SkypeID +
                 "\nTelephone: " + Telephone +
                 "\nPreferred Contact: " + PrefContact +
                 "\nID No: " + ID;
        }
    }
}

And this is my mailing list class:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace BusinessObjects
{
    public class MailingList
    {
        private List<Customer> _list = new List<Customer>();

        public void add(Customer newCustomer)
        {
            _list.Add(newCustomer);
        }

        public Customer find(int id)
        {
            foreach (Customer c in _list)
            {
                if (id == c.ID)
                {
                    return c;
                }
            }

            return null;

        }

        public void delete(int id)
        {
            Customer c = this.find(id);
            if (c != null)
            {
                _list.Remove(c);
            }

        }

        public List<int> ids
        {
            get
            {
               List<int> res = new List<int>();
               foreach(Customer p in _list)
                   res.Add(p.ID);
                return res;
            }

        }

        public void ShowDetails()
        {
            foreach (Customer c in _list)
            {
                MessageBox.Show(c.PrintDetails());
            }
        }
    }
}

Answer 1

Unless you want to use mentioned data bindings you can try this.

Add ListBoxItem instead of string, that way you can access ID without parsing.

lbxCustomers.Items.Add(new ListBoxItem 
{ 
    Tag = cust.ID, 
    Content = cust.FirstName + " " + cust.SecondName
});

Removing from listbox:

ListBoxItem itemToDelete = null;

foreach (ListBoxItem item in listbox.Items)
{
    if (item.Tag == idToDelete)
    {
        itemToDelete = item;
        break;
    }
}

if(itemToDelete != null)
{
    lbxCustomers.Items.Remove(itemToDelete);
}

You might need to cast some variables into proper types.