NotifyParentPropertyAttribute 类

定义

命名空间:

System.ComponentModel

程序集:

System.ComponentModel.Primitives.dll

Source:

NotifyParentPropertyAttribute.cs

指示当此特性应用到的属性的值被修改时，通知父属性。 此类不能被继承。

public ref class NotifyParentPropertyAttribute sealed : Attribute

[System.AttributeUsage(System.AttributeTargets.Property)]
public sealed class NotifyParentPropertyAttribute : Attribute

[<System.AttributeUsage(System.AttributeTargets.Property)>]
type NotifyParentPropertyAttribute = class
    inherit Attribute

Public NotInheritable Class NotifyParentPropertyAttribute
Inherits Attribute

继承

Object

Attribute

NotifyParentPropertyAttribute

属性

AttributeUsageAttribute

示例

下面的代码示例演示如何使用 NotifyParentPropertyAttribute 和 ExpandableObjectConverter 类在自定义控件上创建可展开属性。

using System;
using System.ComponentModel;
using System.Drawing;
using System.Globalization;
using System.Windows.Forms;

namespace ExpandableObjectDemo
{
    public partial class DemoControl : UserControl
    {
        BorderAppearance borderAppearanceValue = new BorderAppearance();
        private System.ComponentModel.IContainer components = null;

        public DemoControl()
        {
            InitializeComponent();
        }

        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        [Browsable(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        [Category("Demo")]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Content)]
        public BorderAppearance Border
        {
            get
            {
                return this.borderAppearanceValue;
            }

            set
            {
                this.borderAppearanceValue = value;
            }
        }

        private void InitializeComponent()
        {
            components = new System.ComponentModel.Container();
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        }
    }

    [TypeConverter(typeof(BorderAppearanceConverter))]
    public class BorderAppearance
    {
        private int borderSizeValue = 1;
        private Color borderColorValue = Color.Empty;

        [Browsable(true),
        NotifyParentProperty(true),
        EditorBrowsable(EditorBrowsableState.Always),
        DefaultValue(1)]
        public int BorderSize
        {
            get
            {
                return borderSizeValue;
            }
            set
            {
                if (value < 0)
                {
                    throw new ArgumentOutOfRangeException(
                        "BorderSize",
                        value,
                        "must be >= 0");
                }

                if (borderSizeValue != value)
                {
                    borderSizeValue = value;
                }
            }
        }

        [Browsable(true)]
        [NotifyParentProperty(true)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        [DefaultValue(typeof(Color), "")]
        public Color BorderColor
        {
            get
            {
                return borderColorValue;
            }
            set
            {
                if (value.Equals(Color.Transparent))
                {
                    throw new NotSupportedException("Transparent colors are not supported.");
                }

                if (borderColorValue != value)
                {
                    borderColorValue = value;
                }
            }
        }
    }

    public class BorderAppearanceConverter : ExpandableObjectConverter
    {
        // This override prevents the PropertyGrid from 
        // displaying the full type name in the value cell.
        public override object ConvertTo(
            ITypeDescriptorContext context,
            CultureInfo culture,
            object value,
            Type destinationType)
        {
            if (destinationType == typeof(string))
            {
                return "";
            }

            return base.ConvertTo(
                context,
                culture,
                value,
                destinationType);
        }
    }
}

Imports System.ComponentModel
Imports System.Drawing
Imports System.Globalization
Imports System.Windows.Forms

Public Class DemoControl
    Inherits UserControl

    Private borderAppearanceValue As New BorderAppearance()
    Private components As System.ComponentModel.IContainer = Nothing


    Public Sub New()
        InitializeComponent()

    End Sub

    Protected Overrides Sub Dispose(ByVal disposing As Boolean)

        If disposing AndAlso (components IsNot Nothing) Then
            components.Dispose()
        End If

        MyBase.Dispose(disposing)

    End Sub

    <Browsable(True), _
    EditorBrowsable(EditorBrowsableState.Always), _
    Category("Demo"), _
    DesignerSerializationVisibility(DesignerSerializationVisibility.Content)> _
    Public Property Border() As BorderAppearance

        Get
            Return Me.borderAppearanceValue
        End Get

        Set(ByVal value As BorderAppearance)
            Me.borderAppearanceValue = value
        End Set

    End Property

    Private Sub InitializeComponent()
        components = New System.ComponentModel.Container()
        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font

    End Sub
End Class

<TypeConverter(GetType(BorderAppearanceConverter))>  _
Public Class BorderAppearance
    Private borderSizeValue As Integer = 1
    Private borderColorValue As Color = Color.Empty
    
    
    <Browsable(True), NotifyParentProperty(True), EditorBrowsable(EditorBrowsableState.Always), DefaultValue(1)>  _
    Public Property BorderSize() As Integer 
        Get
            Return borderSizeValue
        End Get
        Set
            If value < 0 Then
                Throw New ArgumentOutOfRangeException("BorderSize", value, "must be >= 0")
            End If
            
            If borderSizeValue <> value Then
                borderSizeValue = value
            End If
        End Set
    End Property
    
    
    <Browsable(True), NotifyParentProperty(True), EditorBrowsable(EditorBrowsableState.Always), DefaultValue(GetType(Color), "")>  _
    Public Property BorderColor() As Color 
        Get
            Return borderColorValue
        End Get
        Set
            If value.Equals(Color.Transparent) Then
                Throw New NotSupportedException("Transparent colors are not supported.")
            End If
            
            If borderColorValue <> value Then
                borderColorValue = value
            End If
        End Set
    End Property
End Class

Public Class BorderAppearanceConverter
    Inherits ExpandableObjectConverter
    
    ' This override prevents the PropertyGrid from 
    ' displaying the full type name in the value cell.
    Public Overrides Function ConvertTo(ByVal context As ITypeDescriptorContext, ByVal culture As CultureInfo, ByVal value As Object, ByVal destinationType As Type) As Object

        If destinationType Is GetType(String) Then
            Return ""
        End If

        Return MyBase.ConvertTo(context, culture, value, destinationType)

    End Function
End Class

注解

如果属性的父属性应收到属性值更改的通知，则应用于 NotifyParentPropertyAttribute 该属性。 例如，在 属性窗口 中DataGridView.RowTemplate， 属性具有嵌套属性，例如 Height 和 DefaultCellStyle。 这些嵌套属性标记为 ， NotifyParentPropertyAttribute(true) 以便通知父属性更新其值，并在属性值更改时显示。

有关使用特性的详细信息，请参阅 特性。

构造函数

NotifyParentPropertyAttribute(Boolean)

初始化 NotifyParentPropertyAttribute 类的新实例，使用指定的值确定是否通知父属性有关属性值的更改。

字段

Default	指示默认的特性状态，即属性不向父属性通知其值的更改。 此字段为只读。
No	指示不通知父属性有关属性值的更改。 此字段为只读。
Yes	指示通知父属性有关属性值的更改。 此字段为只读。

属性

NotifyParent	获取或设置一个值，该值指示是否应该通知父属性有关属性值的更改。
TypeId	在派生类中实现时，获取此 Attribute 的唯一标识符。 (继承自 Attribute)

方法

Equals(Object)	获取一个值，该值指示指定对象是否与当前对象相同。
GetHashCode()	获取此对象的哈希代码。
GetType()	获取当前实例的 Type。 (继承自 Object)
IsDefaultAttribute()	获取一个值，该值指示该特性的当前值是否为该特性的默认值。
Match(Object)	当在派生类中重写时，返回一个指示此实例是否等于指定对象的值。 (继承自 Attribute)
MemberwiseClone()	创建当前 Object 的浅表副本。 (继承自 Object)
ToString()	返回表示当前对象的字符串。 (继承自 Object)

另请参阅

• ExpandableObjectConverter
• Attribute