I am trying to write a custom date control with 3 drop downs one each
for year, month, day. SelectedDate, MaximumDate, MinimumDate are
properties that the user can set on this control. How can I ensure:
1. The year in drop down is always < MinimumDate.Year
2. Year in drop down <MaximumDate.Year
3. Save view state



using System;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;

namespace datecontrol
{
    /// <summary>
    /// Summary description for WebCustomControl1.
    /// </summary>
    [DefaultProperty("SelectedDate"),
        ToolboxData("<{0}:YearPicker runat=server></{0}:YearPicker>")]
    public class YearPicker : System.Web.UI.WebControls.WebControl
    {
        private DateTime minimumDate = DateTime.MinValue;
        private DateTime maximumDate = DateTime.MaxValue;

        [Bindable(true),
        Category("Appearance"),
        DefaultValue("")]
        public YearPicker()
        {
            month = new DropDownList();
            day = new DropDownList();
            year = new DropDownList();

            month.Items.Add(new ListItem("January", "1"));
            month.Items.Add(new ListItem("Febuary", "2"));
            month.Items.Add(new ListItem("March", "3"));
            month.Items.Add(new ListItem("April", "4"));
            month.Items.Add(new ListItem("May", "5"));
            month.Items.Add(new ListItem("June", "6"));
            month.Items.Add(new ListItem("July", "7"));
            month.Items.Add(new ListItem("August", "8"));
            month.Items.Add(new ListItem("September", "9"));
            month.Items.Add(new ListItem("October", "10"));
            month.Items.Add(new ListItem("November", "11"));
            month.Items.Add(new ListItem("December", "12"));
            month.SelectedValue = DateTime.Now.Month.ToString();

            for (int i = 0; i <= 31; i++)
            {
                day.Items.Add(new ListItem(Convert.ToString(i),
Convert.ToString(i)));
            }
            day.SelectedValue = DateTime.Now.Day.ToString();

            for (int i = minimumDate.Year; i < maximumDate.Year; i++)
            {
                year.Items.Add(new ListItem(Convert.ToString(i),
Convert.ToString(i)));
            }
            year.SelectedValue = DateTime.Now.Year.ToString();
        }

        private DropDownList month;
        private DropDownList day;
        private DropDownList year;
        [Bindable(true),
        Category("SelectedDate"),
        Description("Gets or sets the date.")]
        public DateTime SelectedDate
        {
            get
            {
                DateTime selectedDate = new DateTime(00, 01, 01);
                if (year.SelectedValue != "" && day.SelectedValue !=
"" && month.SelectedValue != "")
                {
                    selectedDate = new
DateTime(Convert.ToInt32(year.SelectedValue),
Convert.ToInt32(month.SelectedValue),
Convert.ToInt32(day.SelectedValue));
                }
                return selectedDate;
            }

            set
            {
                DateTime selectedDate = value;
                month.SelectedValue =
Convert.ToString(selectedDate.Month);
                day.SelectedValue =
Convert.ToString(selectedDate.Day);
                year.SelectedValue =
Convert.ToString(selectedDate.Year);
            }
        }

        [Description("Sets the minimum date")]
        [DefaultValue("")]
        public DateTime MinimumDate
        {
            get
            {
                return minimumDate;
            }
            set
            {
                minimumDate = value;
            }
        }

        [Description("Sets the maximum date")]
        [DefaultValue("")]
        public DateTime MaximumDate
        {
            get
            {
                return maximumDate;
            }
            set
            {
                maximumDate = value;
            }
        }

        [Browsable(false)]
 
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public string GetDay
        {
            get
            {
                return this.day.SelectedValue;
            }
        }

        [Browsable(false)]
 
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public string GetMonth
        {
            get
            {
                return this.month.SelectedValue;
            }
        }

        [Browsable(false)]
 
[DesignerSerializationVisibility(DesignerSerializationVisibility.Hidden)]
        public string GetYear
        {
            get
            {
                return this.year.SelectedValue;
            }
        }

        public DateTime GetDate()
        {
            DateTime result = DateTime.MinValue;

            try
            {
                int day = int.Parse(this.day.SelectedValue);
                int month = int.Parse(this.month.SelectedValue);
                int year = int.Parse(this.year.SelectedValue);

                if (year >= minimumDate.Year && year
<=maximumDate.Year)
                {
                    result = new DateTime(year, month, day);
                }
            }
            catch (FormatException)
            {
                //
                // thrown by the int.Parse
                //
            }
            catch (OverflowException)
            {
                //
                // thrown by the int.Parse
                //
            }
            catch (ArgumentOutOfRangeException)
            {
                //
                // thrown by the DateTime ctor
                //
            }

            return result;
        }

        public void SetDate(DateTime value)
        {
            this.EnsureChildControls();

            if (value == DateTime.MinValue)
            {
                this.day.SelectedValue = string.Empty;
                this.month.SelectedValue = string.Empty;
                this.year.SelectedValue = string.Empty;
            }
            else
            {
                this.day.SelectedValue = value.Day.ToString("00");
                this.month.SelectedValue = value.Month.ToString("00");
                this.year.SelectedValue = value.Year.ToString("00");
            }
        }


        /// <summary>
        /// Render this control to the output parameter specified.
        /// </summary>
        /// <param name="output"> The HTML writer to write out to </
param>
        protected override void Render(HtmlTextWriter output)
        {
            month.RenderControl(output);
            output.Write(" ");
            day.RenderControl(output);
            output.Write(" ");
            year.RenderControl(output);
        }

        protected override object SaveViewState()
        {
            object selectedDate = base.SaveViewState();
            if (year.SelectedValue != "" && day.SelectedValue != "" &&
month.SelectedValue != "")
            {
                selectedDate = new
DateTime(Convert.ToInt32(year.SelectedValue),
Convert.ToInt32(month.SelectedValue),
Convert.ToInt32(day.SelectedValue));
            }
            return selectedDate;
        }

        protected override void LoadViewState(object savedState)
        {
            if (savedState == null) return;

            DateTime state = (DateTime)savedState;
            month.SelectedValue = Convert.ToString(state.Month);
            day.SelectedValue = Convert.ToString(state.Day);
            year.SelectedValue = Convert.ToString(state.Year);
        }
    }
}