Bind listbox selected item focus to button enabled

Thomas Morrison

Hi, I have a listbox which I want the users to be able to remove items from when they select an item then click the delete button. However an error will occur if you try to click remove when having nothing in the list box selected.

lstToSearch.Items.RemoveAt(lstToSearch.SelectedIndex);

Now in the "olden days" I would have to into events such as SelectionChange and have btnRemove.Enabled = True, but I'm sure there must be a more elegant way with data bindings? Am I right?

So to recap, when the user selects an item on the listbox, the remove button becomes enabled. When no item is selected the remove button is disabled

Thanks

Thomas

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Satyapriya Nayak16y ago
Hi Thomas,

Here is a solution :-

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            listBox1.Items.Add("a");
            listBox1.Items.Add("b");
            listBox1.Items.Add("c");
            listBox1.Items.Add("d");
            button1.Enabled = false;

        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {
            visible();
        }

        void visible()
        {

            if (listBox1.Text == "")
            {
                button1.Enabled = false;
            }
            else
            {
                button1.Enabled = true;
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            listBox1.Items.RemoveAt(listBox1.SelectedIndex);
            visible();
        }
    }
}

Thanks

If it helps you plz mark it as Accepted answer
0
Mike Gold16y ago
Are you using Windows Forms or WPF? In Windows Forms you can still trap the SelectionChange event. In WPF there is a more elegant solution with data bindings and value converters. You can bind to your SelectedItem in your listbox and use a value converter to determine if that value is null or not. The binding would look something like (In XAML)
0