C#

<br />
Items.Clear();<br />

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

namespace PCA.SecureWinCtrls
{
    [Description("Control for displaying a time selection combox box with custom time increments. Includes provision for PCA securiyt model."),
    ToolboxBitmap(typeof(ComboBox))]
    public sealed class pcaTimePicker : ComboBox
    {
        #region MEMBERS

        /// <summary>
        /// Override of the base ComboBox property. Style cannot be altered due to the specific
        /// use of this control.
        /// </summary>
        [Browsable(false)]
        public new ComboBoxStyle DropDownStyle
        {
            get
            {
                return ComboBoxStyle.DropDown;
            }
        }

        /// <summary>
        /// Gets the current hours value. If no value is set, and exception will be thrown.
        /// </summary>
        [Browsable(false)]
        public int Hours
        {
            get 
            {
                if (ShowMilitary)
                    return MilHours;
                int i = MilHours;
                if (i > 12)
                    return i - 12;
                else if (i == 0)
                    return 12;
                else
                    return i;
            }
        }

        /// <summary>
        /// Gets the current hours as a military time value, regardless of display mode. If no
        /// value is set, an exception will be thrown.
        /// </summary>
        [Browsable(false)]
        public int MilHours
        {
            get
            {
                ValidateValue(true);
                return DateTime.Parse(Text).Hour;
            }
        }

        /// <summary>
        /// Gets the current minutes value. If no value is set, and exception will be thrown.
        /// </summary>
        [Browsable(false)]
        public int Minutes
        {
            get
            {
                ValidateValue(true);
                return DateTime.Parse(Text).Minute;
            }
        }

        private bool mbMilitary = false;
        /// <summary>
        /// Gets/sets whether the control shows time as a 24-hour clock.
        /// </summary>
        [Description("Gets/sets whether the control shows time as a 24-hour clock."),
        DefaultValue(false)]
        public bool ShowMilitary
        {
            get { return mbMilitary; }
            set
            {
                mbMilitary = value;
                RepopulateChoices();
            }
        }

        private int miIncrement = 30;
        /// <summary>
        /// Gets/sets the increment of the drop-down.
        /// </summary>
        [Description("Gets/sets the increment value in minutes. Valid values are 10 - 720."),
        DefaultValue(30)]
        public int Increment
        {
            get { return miIncrement; }
            set
            {
                if (value < 10 || value > 720)
                {
                    throw new Exception("Increment value must be a value in minutes ranging from 10 to 720 (12 hours).");
                }
                miIncrement = value;
                RepopulateChoices();
            }
        }

        #endregion

        #region EVENT HANDLERS

        /// <summary>
        /// Event fired when the control performs self-validation and fails.
        /// </summary>
        [Description("Event fired when the control loses focus and the text value cannot be parsed as time.")]
        public event EventHandler ValidationFailed;
        /// <summary>
        /// Event fired when the control performs self-validation and succeeds.
        /// </summary>
        public event EventHandler ValidationSucceeded;

        #endregion

        #region PUBLIC METHODS

        /// <summary>
        /// Constructor.
        /// </summary>
        public pcaTimePicker() : base()
        {
            base.DropDownStyle = ComboBoxStyle.DropDown;
            base.Leave += new EventHandler(this_Leave);
            RepopulateChoices();
        }

        /// <summary>
        /// Triggers immediate validation of the control's current value.
        /// </summary>
        /// <param name="bCauseException">Indicates whether an exception should be thrown
        /// if the validation fails.</param>
        public void ForceValidation(bool bCauseException)
        {
            ValidateValue(bCauseException);
        }

        #endregion

        #region PRIVATE METHODS

        /// <summary>
        /// Repopulates the combo box based on the current military and increment settings.
        /// </summary>
        private void RepopulateChoices()
        {
            Items.Clear();
            int i = 0;
            while (i < 1440)
            {
                DateTime dat = new DateTime(1, 1, 1, i / 60, i % 60, 0);
                if (ShowMilitary)
                    Items.Add(dat.ToString("HH:mm"));
                else
                    Items.Add(dat.ToString("h:mm tt"));
                i += Increment;
            }
        }

        /// <summary>
        /// Checkes that the current value of the control is a parsable time.
        /// </summary>
        private void ValidateValue(bool bOnPropertyAccess)
        {
            bool bOK = true;
            try
            {
                DateTime.Parse(base.Text);
            }
            catch (Exception)
            {
                bOK = false;
                if (ValidationFailed != null)
                {
                    ValidationFailed(this, null);
                    if (bOnPropertyAccess)
                        throw;
                }
                else
                    throw;
            }
            if (bOK && ValidationSucceeded != null)
                ValidationSucceeded(this, null);
        }

        #endregion

        #region EVENT HANDLERS

        private void this_Leave(object sender, EventArgs e)
        {
            ValidateValue(false);
        }

        #endregion
    }
}