C# + Xamarin を使用して Android アプリケーションを開発する -- Datetime Picker

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:minWidth="25px"
    android:minHeight="25px">
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linearLayout4">
        <TextView
            android:text="Service Name"
            android:layout_width="400px"
            android:layout_height="match_parent"
            android:id="@+id/lblBdServiceName" />
    </LinearLayout>
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linearLayout1">
        <Button
            android:text="Select Date"
            android:id="@+id/btnBDChooseDate"
            android:layout_width="154.5dp"
            android:layout_height="match_parent" />
        <TextView
            android:text=""
            android:layout_width="400px"
            android:layout_height="match_parent"
            android:id="@+id/lblBDDate" />
    </LinearLayout>
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linearLayout2">
        <Button
            android:text="Select Time"
            android:id="@+id/btnBDChooseTime"
            android:layout_width="154.5dp"
            android:layout_height="match_parent" />
        <TextView
            android:text=""
            android:layout_width="400px"
            android:layout_height="match_parent"
            android:id="@+id/lblBDTime" />
    </LinearLayout>
    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/linearLayout3">
        <TextView
            android:layout_width="154.5dp"
            android:layout_height="match_parent"
            android:id="@+id/lblEmpty" />
        <Button
            android:text="Confirm"
            android:id="@+id/btnBDConfirm"
            android:layout_width="154.5dp"
            android:layout_height="match_parent"
            android:layout_marginRight="320.8dp" />
    </LinearLayout>
</LinearLayout>

public class BookingDetails : Activity
    {

        private TextView timeDisplay;
        private Button pickTime;
        private int hour;
        private int minute;
        const int TIME_DIALOG_ID = 0;



        private TextView dateDisplay;
        private Button pickDate;
        private DateTime date;
        const int DATE_DIALOG_ID = 1;

        private DateTime serverDateTime ;

        protected override void OnCreate(Bundle bundle)
        {
            SetContentView(Resource.Layout.BookingDetails);
            base.OnCreate(bundle);

            try
            {
                var lblServiceName = FindViewById<TextView>(Resource.Id.lblBdServiceName);
                lblServiceName.SetText("Service 1", TextView.BufferType.Normal);

                serverDateTime = DateTime.Parse("2015-5-22 15:30:26");
                // Create your application here

                timeDisplay = FindViewById<TextView>(Resource.Id.lblBDTime);
                pickTime = FindViewById<Button>(Resource.Id.btnBDChooseTime);

                // Add a click listener to the button
                pickTime.Click += (o, e) => ShowDialog(TIME_DIALOG_ID);

                hour = serverDateTime.Hour;
                minute = serverDateTime.Minute;
                UpdateDisplayTime();



                // capture our View elements
                dateDisplay = FindViewById<TextView>(Resource.Id.lblBDDate);
                pickDate = FindViewById<Button>(Resource.Id.btnBDChooseDate);

                // add a click event handler to the button
                pickDate.Click += delegate { ShowDialog(DATE_DIALOG_ID); };

                date = serverDateTime;
                UpdateDisplayDate();


                var btnCfm = FindViewById<Button>(Resource.Id.btnBDConfirm);
                btnCfm.Click += (sender, args) =>
                {
                    try
                    {
                        var serviceName = FindViewById<TextView>(Resource.Id.lblBdServiceName).Text;
                        var selectDate = FindViewById<TextView>(Resource.Id.lblBDDate).Text;
                        var selectTime = FindViewById<TextView>(Resource.Id.lblBDTime).Text;

                        var selectedDateTime =
                           DateTime.Parse(string.Format("{0} {1}", selectDate, selectTime)).ToString();
                        var msg = string.Format("Confirm booking service &#39;{0}&#39; at {1} ?", serviceName, selectedDateTime);
                        this.ShowDlgYesNo(msg, "Booking Confirmation",
                            (s, arg) =>
                            {
                                this.ShowAlert("call api book");
                                this.GotoActicity<MainActivity>();
                            },
                            (s, arg) =>
                            {
                                // do nothing 
                            });
                    }
                    catch (Exception ex)
                    {
                        this.ShowAlert(ex.Message);
                    }

                    
                };
            }
            catch (Exception ex)
            {
                this.ShowAlert(ex.Message);
            }
           
        }

        private void UpdateDisplayTime()
        {
            string time = string.Format("{0}:{1}", hour, minute.ToString().PadLeft(2, &#39;0&#39;));
            timeDisplay.Text = time;

        }

        private void UpdateDisplayDate()
        {
            dateDisplay.Text = date.ToString("d");
        }

        private void TimePickerCallback(object sender, TimePickerDialog.TimeSetEventArgs e)
        {
            hour = e.HourOfDay;
            minute = e.Minute;
            UpdateDisplayTime();
        }

        void OnDateSet(object sender, DatePickerDialog.DateSetEventArgs e)
        {
            this.date = e.Date;
            UpdateDisplayDate();
        }

        protected override Dialog OnCreateDialog(int id)
        {
            if (id == TIME_DIALOG_ID)
            {
                return new TimePickerDialog(this, TimePickerCallback, hour, minute, false);
            }
            if (id == DATE_DIALOG_ID)
            {
                var dlg = new DatePickerDialog(this, OnDateSet, serverDateTime.Year, serverDateTime.Month-1, serverDateTime.Day);
                return dlg;
            }

            return null;
        }
    }