VB.NET TemplatedControlDesigner类代码示例

' 导入命名空间
Imports System.ComponentModel
Imports System.Web.UI
Imports System.Web.UI.WebControls
Imports System.Web.UI.Design

Namespace ASPNet.Design.Samples

    ' Set an attribute reference to the designer, and define 
    ' the HTML markup that the toolbox will write into the source.
    <Designer(GetType(TemplateGroupsSampleDesigner)), _
        ToolboxData("<{0}:TemplateGroupsSample runat=server></{0}:TemplateGroupsSample>")> _
    Public Class TemplateGroupsSample
        Inherits WebControl
        Implements INamingContainer

        ' Field for the templates
        Private _templates() As ITemplate

        ' Constructor
        Public Sub New()
            ReDim _templates(4)
        End Sub

        ' For each template property, set the designer attributes 
        ' so the property does not appear in the property grid, but 
        ' changes to the template are persisted in the control.
        <Browsable(False), _
            PersistenceMode(PersistenceMode.InnerProperty)> _
        Public Property Template1() As ITemplate
            Get
                Return _templates(0)
            End Get
            Set(ByVal Value As ITemplate)
                _templates(0) = Value
            End Set
        End Property
        <Browsable(False), _
            PersistenceMode(PersistenceMode.InnerProperty)> _
        Public Property Template2() As ITemplate
            Get
                Return _templates(1)
            End Get
            Set(ByVal Value As ITemplate)
                _templates(1) = Value
            End Set
        End Property
        <Browsable(False), _
            PersistenceMode(PersistenceMode.InnerProperty)> _
        Public Property Template3() As ITemplate
            Get
                Return _templates(2)
            End Get
            Set(ByVal Value As ITemplate)
                _templates(2) = Value
            End Set
        End Property
        <Browsable(False), _
            PersistenceMode(PersistenceMode.InnerProperty)> _
        Public Property Template4() As ITemplate
            Get
                Return _templates(3)
            End Get
            Set(ByVal Value As ITemplate)
                _templates(3) = Value
            End Set
        End Property

        Protected Overrides Sub CreateChildControls()
            ' Instantiate the template inside the panel
            ' then add the panel to the Controls collection
            Dim i As Integer

            For i = 0 To 3
                Dim pan As New Panel()
                _templates(i).InstantiateIn(pan)
                Me.Controls.Add(pan)
            Next
        End Sub

    End Class

    ' Designer for the TemplateGroupsSample class
    Public Class TemplateGroupsSampleDesigner
        Inherits System.Web.UI.Design.ControlDesigner

        Private col As TemplateGroupCollection = Nothing

        Public Overrides Sub Initialize(ByVal Component As IComponent)
            ' Initialize the base
            MyBase.Initialize(Component)
            ' Turn on template editing
            SetViewFlags(ViewFlags.TemplateEditing, True)
        End Sub

        ' Add instructions to the placeholder view of the control
        Public Overloads Overrides Function GetDesignTimeHtml() As String
            Return CreatePlaceHolderDesignTimeHtml("Click here and use " & _
                "the task menu to edit the templates.")
        End Function

        Public Overrides ReadOnly Property TemplateGroups() As TemplateGroupCollection
            Get
                If IsNothing(col) Then
                    ' Get the base collection
                    col = MyBase.TemplateGroups

                    ' Create variables
                    Dim tempGroup As TemplateGroup
                    Dim tempDef As TemplateDefinition
                    Dim ctl As TemplateGroupsSample

                    ' Get reference to the component as TemplateGroupsSample
                    ctl = CType(Component, TemplateGroupsSample)

                    ' Create a TemplateGroup
                    tempGroup = New TemplateGroup("Template Set A")

                    ' Create a TemplateDefinition
                    tempDef = New TemplateDefinition(Me, "Template A1", ctl, "Template1", True)

                    ' Add the TemplateDefinition to the TemplateGroup
                    tempGroup.AddTemplateDefinition(tempDef)

                    ' Create another TemplateDefinition
                    tempDef = New TemplateDefinition(Me, "Template A2", ctl, "Template2", True)

                    ' Add the TemplateDefinition to the TemplateGroup
                    tempGroup.AddTemplateDefinition(tempDef)

                    ' Add the TemplateGroup to the TemplateGroupCollection
                    col.Add(tempGroup)

                    ' Create another TemplateGroup and populate it
                    tempGroup = New TemplateGroup("Template Set B")
                    tempDef = New TemplateDefinition(Me, "Template B1", ctl, "Template3", True)
                    tempGroup.AddTemplateDefinition(tempDef)
                    tempDef = New TemplateDefinition(Me, "Template B2", ctl, "Template4", True)
                    tempGroup.AddTemplateDefinition(tempDef)

                    ' Add the TemplateGroup to the TemplateGroupCollection
                    col.Add(tempGroup)
                End If

                Return col
            End Get
        End Property

        ' Do not allow direct resizing unless in TemplateMode
        Public Overrides ReadOnly Property AllowResize() As Boolean
            Get
                If Me.InTemplateMode Then
                    Return True
                Else
                    Return False
                End If
            End Get
        End Property
    End Class
End Namespace