Практическое руководство. Заключение элемента управления в оболочку ToolStripControlHost в Windows Forms

Статья
11/05/2008

Обновлен: Ноябрь 2007

Оболочка ToolStripControlHost предназначена для размещения произвольных элементов управления Windows Forms с помощью конструктора ToolStripControlHost либо путем расширения самой оболочки ToolStripControlHost. Она позволяет упростить создание программы-оболочки для элемента управления путем расширения ToolStripControlHost и реализации свойств и методов, открывающих доступ к часто используемым свойствам и методом элемента управления. Кроме того, на уровне ToolStripControlHost можно предоставить доступ к методам элемента управления.

Заключение элемента управления в оболочку ToolStripControlHost путем наследования

Создайте расширение класса ToolStripControlHost. Реализуйте конструктор по умолчанию, вызывающий конструктор базового класса и передающий ему требуемый элемент управления.
```
' Call the base constructor passing in a MonthCalendar instance.
Public Sub New() 
    MyBase.New(New MonthCalendar())

End Sub
```
```
     // Call the base constructor passing in a MonthCalendar instance.
        public ToolStripMonthCalendar() : base (new MonthCalendar()) { }
```
Объявите свойство того же типа, что и заключаемый в оболочку элемент управления, а в методе доступа для свойства укажите Control в качестве возвращаемого типа элемента управления.
```
Public ReadOnly Property MonthCalendarControl() As MonthCalendar 
    Get
        Return CType(Control, MonthCalendar)
    End Get
End Property
```
```
     public MonthCalendar MonthCalendarControl
        {
            get
            {
                return Control as MonthCalendar;
            }
        }
```

Обеспечьте доступ к часто используемым свойствам и методам заключаемого в оболочку элемента управления с помощью свойств и методов расширенного класса.

' Expose the MonthCalendar.FirstDayOfWeek as a property.
Public Property FirstDayOfWeek() As Day 
    Get
        Return MonthCalendarControl.FirstDayOfWeek
    End Get
    Set
        value = MonthCalendarControl.FirstDayOfWeek
    End Set
End Property

' Expose the AddBoldedDate method.
Public Sub AddBoldedDate(ByVal dateToBold As DateTime) 
    MonthCalendarControl.AddBoldedDate(dateToBold)

End Sub

     // Expose the MonthCalendar.FirstDayOfWeek as a property.
        public Day FirstDayOfWeek
        {
            get
            {
                return MonthCalendarControl.FirstDayOfWeek;
            }
            set { value = MonthCalendarControl.FirstDayOfWeek; }
        }

        // Expose the AddBoldedDate method.
        public void AddBoldedDate(DateTime dateToBold)
        {
            MonthCalendarControl.AddBoldedDate(dateToBold);
        }

При необходимости можно переопределить методы OnSubscribeControlEvents и OnUnsubscribeControlEvents и добавить события элемента управления, к которым требуется открыть доступ.

Protected Overrides Sub OnSubscribeControlEvents(ByVal c As Control) 

    ' Call the base so the base events are connected.
    MyBase.OnSubscribeControlEvents(c)

    ' Cast the control to a MonthCalendar control.
    Dim monthCalendarControl As MonthCalendar = _
        CType(c, MonthCalendar)

    ' Add the event.
    AddHandler monthCalendarControl.DateChanged, _
        AddressOf HandleDateChanged

End Sub

Protected Overrides Sub OnUnsubscribeControlEvents(ByVal c As Control)
    ' Call the base method so the basic events are unsubscribed.
    MyBase.OnUnsubscribeControlEvents(c)

    ' Cast the control to a MonthCalendar control.
    Dim monthCalendarControl As MonthCalendar = _
        CType(c, MonthCalendar)

    ' Remove the event.
    RemoveHandler monthCalendarControl.DateChanged, _
        AddressOf HandleDateChanged

End Sub

     protected override void OnSubscribeControlEvents(Control c)
        {
            // Call the base so the base events are connected.
            base.OnSubscribeControlEvents(c);

            // Cast the control to a MonthCalendar control.
            MonthCalendar monthCalendarControl = (MonthCalendar) c;

            // Add the event.
            monthCalendarControl.DateChanged +=
                new DateRangeEventHandler(OnDateChanged);
        }

        protected override void OnUnsubscribeControlEvents(Control c)
        {
            // Call the base method so the basic events are unsubscribed.
            base.OnUnsubscribeControlEvents(c);

            // Cast the control to a MonthCalendar control.
            MonthCalendar monthCalendarControl = (MonthCalendar) c;

            // Remove the event.
            monthCalendarControl.DateChanged -=
                new DateRangeEventHandler(OnDateChanged);
        }

Обеспечьте оболочку для событий, к которым необходимо открыть доступ.

    ' Declare the DateChanged event.
    Public Event DateChanged As DateRangeEventHandler

    ' Raise the DateChanged event.
    Private Sub HandleDateChanged(ByVal sender As Object, _
        ByVal e As DateRangeEventArgs)

        RaiseEvent DateChanged(Me, e)
    End Sub
End Class

     // Declare the DateChanged event.
        public event DateRangeEventHandler DateChanged;

        // Raise the DateChanged event.
        private void OnDateChanged(object sender, DateRangeEventArgs e)
        {
            if (DateChanged != null)
            {
                DateChanged(this, e);
            }
        }

Пример

'Declare a class that inherits from ToolStripControlHost.

Public Class ToolStripMonthCalendar
    Inherits ToolStripControlHost

    ' Call the base constructor passing in a MonthCalendar instance.
    Public Sub New() 
        MyBase.New(New MonthCalendar())

    End Sub

    Public ReadOnly Property MonthCalendarControl() As MonthCalendar 
        Get
            Return CType(Control, MonthCalendar)
        End Get
    End Property

    ' Expose the MonthCalendar.FirstDayOfWeek as a property.
    Public Property FirstDayOfWeek() As Day 
        Get
            Return MonthCalendarControl.FirstDayOfWeek
        End Get
        Set
            value = MonthCalendarControl.FirstDayOfWeek
        End Set
    End Property

    ' Expose the AddBoldedDate method.
    Public Sub AddBoldedDate(ByVal dateToBold As DateTime) 
        MonthCalendarControl.AddBoldedDate(dateToBold)

    End Sub

    ' Subscribe and unsubscribe the control events you wish to expose.
    Protected Overrides Sub OnSubscribeControlEvents(ByVal c As Control) 

        ' Call the base so the base events are connected.
        MyBase.OnSubscribeControlEvents(c)

        ' Cast the control to a MonthCalendar control.
        Dim monthCalendarControl As MonthCalendar = _
            CType(c, MonthCalendar)

        ' Add the event.
        AddHandler monthCalendarControl.DateChanged, _
            AddressOf HandleDateChanged

    End Sub

    Protected Overrides Sub OnUnsubscribeControlEvents(ByVal c As Control)
        ' Call the base method so the basic events are unsubscribed.
        MyBase.OnUnsubscribeControlEvents(c)

        ' Cast the control to a MonthCalendar control.
        Dim monthCalendarControl As MonthCalendar = _
            CType(c, MonthCalendar)

        ' Remove the event.
        RemoveHandler monthCalendarControl.DateChanged, _
            AddressOf HandleDateChanged

    End Sub

    ' Declare the DateChanged event.
    Public Event DateChanged As DateRangeEventHandler

    ' Raise the DateChanged event.
    Private Sub HandleDateChanged(ByVal sender As Object, _
        ByVal e As DateRangeEventArgs)

        RaiseEvent DateChanged(Me, e)
    End Sub
End Class

 //Declare a class that inherits from ToolStripControlHost.
    public class ToolStripMonthCalendar : ToolStripControlHost
    {
        // Call the base constructor passing in a MonthCalendar instance.
        public ToolStripMonthCalendar() : base (new MonthCalendar()) { }

        public MonthCalendar MonthCalendarControl
        {
            get
            {
                return Control as MonthCalendar;
            }
        }

        // Expose the MonthCalendar.FirstDayOfWeek as a property.
        public Day FirstDayOfWeek
        {
            get
            {
                return MonthCalendarControl.FirstDayOfWeek;
            }
            set { value = MonthCalendarControl.FirstDayOfWeek; }
        }

        // Expose the AddBoldedDate method.
        public void AddBoldedDate(DateTime dateToBold)
        {
            MonthCalendarControl.AddBoldedDate(dateToBold);
        }

        // Subscribe and unsubscribe the control events you wish to expose.
        protected override void OnSubscribeControlEvents(Control c)
        {
            // Call the base so the base events are connected.
            base.OnSubscribeControlEvents(c);

            // Cast the control to a MonthCalendar control.
            MonthCalendar monthCalendarControl = (MonthCalendar) c;

            // Add the event.
            monthCalendarControl.DateChanged +=
                new DateRangeEventHandler(OnDateChanged);
        }

        protected override void OnUnsubscribeControlEvents(Control c)
        {
            // Call the base method so the basic events are unsubscribed.
            base.OnUnsubscribeControlEvents(c);

            // Cast the control to a MonthCalendar control.
            MonthCalendar monthCalendarControl = (MonthCalendar) c;

            // Remove the event.
            monthCalendarControl.DateChanged -=
                new DateRangeEventHandler(OnDateChanged);
        }

        // Declare the DateChanged event.
        public event DateRangeEventHandler DateChanged;

        // Raise the DateChanged event.
        private void OnDateChanged(object sender, DateRangeEventArgs e)
        {
            if (DateChanged != null)
            {
                DateChanged(this, e);
            }
        }
    }