Setting a button enabled after all fields are filled in

Question

I have a window with three textboxes and a button. Is there a way to check if all fields have a value in each before setting the button enabled. It matters not what is in each box, rather each box has an entry.

Thanks

Answer 1

The easiest is setting the button as disabled first, then handling TextChanged event of all text boxes with the same handler and enable the button only if all those text boxes have value:

using System;
using System.Windows.Forms;

namespace WindowsFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            button1.Enabled = false;
            textBox1.TextChanged += TextBox_TextChanged;
            textBox2.TextChanged += TextBox_TextChanged;
            textBox3.TextChanged += TextBox_TextChanged;
        }

        private void TextBox_TextChanged(object sender, EventArgs e)
        {
            button1.Enabled = !string.IsNullOrEmpty(textBox1.Text)
                && !string.IsNullOrEmpty(textBox2.Text)
                && !string.IsNullOrEmpty(textBox3.Text);
        }
    }
}