Force to close MessageBox programmatically

Question

Let me give you the background.

We have an Application(medium sized) that is using MessageBox.Show (....) at various places (in hundreds).

These message bo

Answer 1

This topic has been abundantly covered in other SO questions but since this particular one has several answers about using UI automation/window lookup techniques (which I don't particularly like) and generic suggestions about creating own dialog without provided code, I decided post my own solution. One can create an instantiable MessageBox like class as it follows:

using System;
using System.Drawing;
using System.Linq;
using System.Windows.Forms;
using System.Text.RegularExpressions;

namespace Common
{
    // Loosely based on: https://www.codeproject.com/Articles/17253/A-Custom-Message-Box
    class MsgBox : Form
    {
        private Panel _plHeader = new Panel();
        private Panel _plFooter = new Panel();
        private Panel _plIcon = new Panel();
        private PictureBox _picIcon = new PictureBox();
        private FlowLayoutPanel _flpButtons = new FlowLayoutPanel();
        private Label _lblMessage;

        private MsgBox()
        {
            FormBorderStyle = FormBorderStyle.FixedDialog;
            BackColor = Color.White;
            StartPosition = FormStartPosition.CenterScreen;
            MinimizeBox = false;
            MaximizeBox = false;
            ShowIcon = false;
            Width = 400;

            _lblMessage = new Label();
            _lblMessage.Font = new Font("Segoe UI", 10);
            _lblMessage.Dock = DockStyle.Fill;
            _lblMessage.TextAlign = ContentAlignment.MiddleLeft;

            _flpButtons.FlowDirection = FlowDirection.RightToLeft;
            _flpButtons.Dock = DockStyle.Fill;

            //_plHeader.FlowDirection = FlowDirection.TopDown;
            _plHeader.Dock = DockStyle.Fill;
            _plHeader.Padding = new Padding(20);
            _plHeader.Controls.Add(_lblMessage);

            _plFooter.Dock = DockStyle.Bottom;
            _plFooter.BackColor = Color.FromArgb(240, 240, 240);
            _plFooter.Padding = new Padding(10);
            _plFooter.Height = 60;
            _plFooter.Controls.Add(_flpButtons);

            _picIcon.Location = new Point(30, 50);

            _plIcon.Dock = DockStyle.Left;
            _plIcon.Padding = new Padding(20);
            _plIcon.Width = 70;
            _plIcon.Controls.Add(_picIcon);

            Controls.Add(_plHeader);
            Controls.Add(_plIcon);
            Controls.Add(_plFooter);
        }

        public static DialogResult Show(IWin32Window owner, string message, string title = null, MessageBoxButtons? buttons = MessageBoxButtons.OK, MessageBoxIcon icon = MessageBoxIcon.Information)
        {
            var msgBox = Create(message, title, buttons, icon);
            return msgBox.ShowDialog(owner);
        }

        public static DialogResult Show(string message, string title = null, MessageBoxButtons? buttons = MessageBoxButtons.OK, MessageBoxIcon icon = MessageBoxIcon.Information)
        {
            var msgBox = Create(message, title, buttons, icon);
            return msgBox.ShowDialog();
        }

        public static MsgBox Create(string message, string title = null, MessageBoxButtons? buttons = MessageBoxButtons.OK, MessageBoxIcon icon = MessageBoxIcon.Information)
        {
            var msgBox = new MsgBox();
            msgBox.Init(message, title, buttons, icon);
            return msgBox;
        }

        void Init(string message, string title, MessageBoxButtons? buttons, MessageBoxIcon icon)
        {
            _lblMessage.Text = message;
            Text = title;
            InitButtons(buttons);
            InitIcon(icon);
            Size = MessageSize(message);
        }

        void InitButtons(MessageBoxButtons? buttons)
        {
            if (!buttons.HasValue)
                return;

            switch (buttons)
            {
                case MessageBoxButtons.AbortRetryIgnore:
                    AddButton("Ignore");
                    AddButton("Retry");
                    AddButton("Abort");
                    break;

                case MessageBoxButtons.OK:
                    AddButton("OK");
                    break;

                case MessageBoxButtons.OKCancel:
                    AddButton("Cancel");
                    AddButton("OK");
                    break;

                case MessageBoxButtons.RetryCancel:
                    AddButton("Cancel");
                    AddButton("Retry");
                    break;

                case MessageBoxButtons.YesNo:
                    AddButton("No");
                    AddButton("Yes");
                    break;

                case MessageBoxButtons.YesNoCancel:
                    AddButton("Cancel");
                    AddButton("No");
                    AddButton("Yes");
                    break;
            }
        }

        void InitIcon(MessageBoxIcon icon)
        {
            switch (icon)
            {
                case MessageBoxIcon.None:
                    _picIcon.Hide();
                    break;
                case MessageBoxIcon.Exclamation:
                    _picIcon.Image = SystemIcons.Exclamation.ToBitmap();
                    break;

                case MessageBoxIcon.Error:
                    _picIcon.Image = SystemIcons.Error.ToBitmap();
                    break;

                case MessageBoxIcon.Information:
                    _picIcon.Image = SystemIcons.Information.ToBitmap();
                    break;

                case MessageBoxIcon.Question:
                    _picIcon.Image = SystemIcons.Question.ToBitmap();
                    break;
            }

            _picIcon.Width = _picIcon.Image.Width;
            _picIcon.Height = _picIcon.Image.Height;
        }

        private void ButtonClick(object sender, EventArgs e)
        {
            Button btn = (Button)sender;

            switch (btn.Text)
            {
                case "Abort":
                    DialogResult = DialogResult.Abort;
                    break;

                case "Retry":
                    DialogResult = DialogResult.Retry;
                    break;

                case "Ignore":
                    DialogResult = DialogResult.Ignore;
                    break;

                case "OK":
                    DialogResult = DialogResult.OK;
                    break;

                case "Cancel":
                    DialogResult = DialogResult.Cancel;
                    break;

                case "Yes":
                    DialogResult = DialogResult.Yes;
                    break;

                case "No":
                    DialogResult = DialogResult.No;
                    break;
            }

            Close();
        }

        private static Size MessageSize(string message)
        {
            int width=350;
            int height = 230;

            SizeF size = TextRenderer.MeasureText(message, new Font("Segoe UI", 10));

            if (message.Length < 150)
            {
                if ((int)size.Width > 350)
                {
                    width = (int)size.Width;
                }
            }
            else
            {
                string[] groups = (from Match m in Regex.Matches(message, ".{1,180}") select m.Value).ToArray();
                int lines = groups.Length+1;
                width = 700;
                height += (int)(size.Height+10) * lines;
            }
            return new Size(width, height);
        }

        private void AddButton(string caption)
        {
            var btn = new Button();
            btn.Text = caption;
            btn.Font = new Font("Segoe UI", 8);
            btn.BackColor = Color.FromArgb(225, 225, 225);
            btn.Padding = new Padding(3);
            btn.Height = 30;
            btn.Click += ButtonClick;
            _flpButtons.Controls.Add(btn);
        }
    }
}

One can then just keep the reference of the dialog in a class scope, show the dialog and get the result, or just close it in an application exit event handler.

MsgBox _msgBox;

void eventHandler1(object sender, EventArgs e)
{
    _msgBox = MsgBox.Create("Do you want to continue", "Inquiry", MessageBoxButtons.YesNo);
    var result = _msgBox.ShowDialog();
    // do something with result
}

void applicationExitHandler(object sender, EventArgs e)
{
    if (_msgBox != null)
        _msgBox.Close();
}