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c# - 设计时用户控件中的集合编辑器

转载 作者:行者123 更新时间:2023-11-30 16:36:21 33 4
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我在 Windows 应用程序项目中有一个 UserControl 类。它的一个属性是我定义的另一个类的集合。我似乎找不到一个很好的例子来说明如何在设计时让标准集合编辑器为它工作。

我在一定程度上使用我发现的一些示例代码让它工作,但我的集合中的数据没有得到保存。当我退出表单并在设计时重新打开它时,数据不再存在。

这是我的类(class):

Public Class Gauge
Inherits Control

Private WithEvents _Captions As New CaptionCollection

<Category("Gauge"), _
TypeConverter(GetType(CaptionCollectionConverter)), _
Description("Custom text displayed on the gauge.")> _
Public Property Captions() As CaptionCollection
Get
Return _Captions
End Get
Set(ByVal value As CaptionCollection)
_Captions = value
End Set
End Property

<Category("Gauge"), _
TypeConverter(GetType(CaptionConverter)), _
Description("Custom text displayed on the gauge.")> _
Public Class Caption
Private _Text As String = ""
Private _Color As Color = Color.Black
Private _TextIsValue As Boolean
Private _Position As New Point(0, 0)

Public Property Text() As String
Get
Return _Text
End Get
Set(ByVal value As String)
If _Text <> value Then
_Text = value
End If
End Set
End Property

Public Property Color() As Color
Get
Return _Color
End Get
Set(ByVal value As Color)
If _Color <> value Then
_Color = value
End If
End Set
End Property

Public Property TextIsValue() As Boolean
Get
Return _TextIsValue
End Get
Set(ByVal value As Boolean)
If _TextIsValue <> value Then
_TextIsValue = value
End If
End Set
End Property

Public Property Position() As Point
Get
Return _Position
End Get
Set(ByVal value As Point)
If _Position <> value Then
_Position = value
End If
End Set
End Property
End Class

Public Class CaptionCollection
Inherits CollectionBase
Implements ICustomTypeDescriptor

Public Sub Add(ByVal c As Caption)
Me.List.Add(c)
End Sub

Public Sub Remove(ByVal c As Caption)
Me.List.Remove(c)
End Sub

Default Public ReadOnly Property Item(ByVal index As Integer) As Caption
Get
Return DirectCast(Me.List(index), Caption)
End Get
End Property

' Implementation of interface ICustomTypeDescriptor
Public Function GetClassName() As String Implements System.ComponentModel.ICustomTypeDescriptor.GetClassName
Return TypeDescriptor.GetClassName(Me, True)
End Function

Public Function GetAttributes() As AttributeCollection Implements System.ComponentModel.ICustomTypeDescriptor.GetAttributes
Return TypeDescriptor.GetAttributes(Me, True)
End Function

Public Function GetComponentName() As String Implements System.ComponentModel.ICustomTypeDescriptor.GetComponentName
Return TypeDescriptor.GetComponentName(Me, True)
End Function

Public Function GetConverter() As TypeConverter Implements System.ComponentModel.ICustomTypeDescriptor.GetConverter
Return TypeDescriptor.GetConverter(Me, True)
End Function

Public Function GetDefaultEvent() As EventDescriptor Implements System.ComponentModel.ICustomTypeDescriptor.GetDefaultEvent
Return TypeDescriptor.GetDefaultEvent(Me, True)
End Function

Public Function GetDefaultProperty() As PropertyDescriptor Implements System.ComponentModel.ICustomTypeDescriptor.GetDefaultProperty
Return TypeDescriptor.GetDefaultProperty(Me, True)
End Function

Public Function GetEditor(ByVal editorBaseType As Type) As Object Implements System.ComponentModel.ICustomTypeDescriptor.GetEditor
Return TypeDescriptor.GetEditor(Me, editorBaseType, True)
End Function

Public Function GetEvents(ByVal attributes As Attribute()) As EventDescriptorCollection Implements System.ComponentModel.ICustomTypeDescriptor.GetEvents
Return TypeDescriptor.GetEvents(Me, attributes, True)
End Function

Public Function GetEvents() As EventDescriptorCollection Implements System.ComponentModel.ICustomTypeDescriptor.GetEvents
Return TypeDescriptor.GetEvents(Me, True)
End Function

Public Function GetPropertyOwner(ByVal pd As PropertyDescriptor) As Object Implements System.ComponentModel.ICustomTypeDescriptor.GetPropertyOwner
Return Me
End Function

Public Function GetProperties(ByVal attributes As Attribute()) As PropertyDescriptorCollection Implements System.ComponentModel.ICustomTypeDescriptor.GetProperties
Return GetProperties()
End Function

Public Function GetProperties() As PropertyDescriptorCollection Implements System.ComponentModel.ICustomTypeDescriptor.GetProperties
' Create a collection object to hold property descriptors
Dim pds As New PropertyDescriptorCollection(Nothing)

' Iterate the list of employees
For i As Integer = 0 To Me.List.Count - 1
' Create a property descriptor for the caption item and add to the property descriptor collection
Dim pd As New CaptionCollectionPropertyDescriptor(Me, i)
pds.Add(pd)
Next
' return the property descriptor collection
Return pds
End Function
End Class

' This is a special type converter which will be associated with the Caption class.
' It converts a Caption object to string representation for use in a property grid.
Friend Class CaptionConverter
Inherits ExpandableObjectConverter

Public Overloads Overrides Function ConvertTo(ByVal context As ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object, ByVal destType As Type) As Object
'Return "(Collection)"
If destType Is GetType(String) AndAlso TypeOf value Is Caption Then
' Cast the value to an Caption type
Dim emp As Caption = DirectCast(value, Caption)
' Return the text for display.
Return emp.Text
End If
Return MyBase.ConvertTo(context, culture, value, destType)
End Function
End Class

' This is a special type converter which will be associated with the CaptionCollection class.
' It converts a CaptionCollection object to a string representation for use in a property grid.
Friend Class CaptionCollectionConverter
Inherits ExpandableObjectConverter

Public Overloads Overrides Function ConvertTo(ByVal context As ITypeDescriptorContext, ByVal culture As System.Globalization.CultureInfo, ByVal value As Object, ByVal destType As Type) As Object
If destType Is GetType(String) AndAlso TypeOf value Is CaptionCollection Then
' Return department and department role separated by comma.
Return "(Collection)"
End If
Return MyBase.ConvertTo(context, culture, value, destType)
End Function
End Class

Public Class CaptionCollectionPropertyDescriptor
Inherits PropertyDescriptor
Private collection As CaptionCollection = Nothing
Private index As Integer = -1

Public Sub New(ByVal coll As CaptionCollection, ByVal idx As Integer)
MyBase.New("#" & idx.ToString(), Nothing)
Me.collection = coll
Me.index = idx
End Sub

Public Overloads Overrides ReadOnly Property Attributes() As AttributeCollection
Get
Return New AttributeCollection(Nothing)
End Get
End Property

Public Overloads Overrides Function CanResetValue(ByVal component As Object) As Boolean
Return True
End Function

Public Overloads Overrides ReadOnly Property ComponentType() As Type
Get
Return Me.collection.[GetType]()
End Get
End Property

Public Overloads Overrides ReadOnly Property DisplayName() As String
Get
Return "Caption" + (index + 1).ToString()
End Get
End Property

Public Overloads Overrides ReadOnly Property Description() As String
Get
Return "Caption" + (index + 1).ToString()
End Get
End Property

Public Overloads Overrides Function GetValue(ByVal component As Object) As Object
Return Me.collection(index)
End Function

Public Overloads Overrides ReadOnly Property IsReadOnly() As Boolean
Get
Return False
End Get
End Property

Public Overloads Overrides ReadOnly Property Name() As String
Get
Return "#" & index.ToString()
End Get
End Property

Public Overloads Overrides ReadOnly Property PropertyType() As Type
Get
Return Me.collection(index).[GetType]()
End Get
End Property

Public Overloads Overrides Sub ResetValue(ByVal component As Object)
End Sub

Public Overloads Overrides Function ShouldSerializeValue(ByVal component As Object) As Boolean
Return True
End Function

Public Overloads Overrides Sub SetValue(ByVal component As Object, ByVal value As Object)
' this.collection[index] = value;
End Sub
End Class

下课

最佳答案

我找到了答案。我缺少的是 Captions 属性中的这个属性:DesignerSerializationVisibility(DesignerSerializationVisibility.Content

关于c# - 设计时用户控件中的集合编辑器,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/964912/

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