ComponentEditor Class
Provides the base class for a custom component editor.
Assembly: System (in System.dll)
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The HostProtectionAttribute attribute applied to this type or member has the following Resources property value: SharedState. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
A component editor is used to edit a component as a whole and can be used to implement a user interface similar to that of the property pages. You associate a component editor with a component by using the EditorAttribute attribute.
Notes to Inheritors:When you inherit from this class, you must override the EditComponent method.
The following code example demonstrates an example ComponentEditor implementation.
Imports System Imports System.ComponentModel Imports System.ComponentModel.Design Imports System.Collections Imports System.Drawing Imports System.IO Imports System.Runtime.Serialization Imports System.Runtime.Serialization.Formatters.Binary Imports System.Windows.Forms Imports System.Windows.Forms.Design ' This example demonstrates how to implement a component editor that hosts ' component pages and associate it with a component. This example also ' demonstrates how to implement a component page that provides a panel-based ' control system and Help keyword support. ' The ExampleComponentEditor displays two ExampleComponentEditorPage pages. Public Class ExampleComponentEditor Inherits System.Windows.Forms.Design.WindowsFormsComponentEditor ' This method override returns an type array containing the type of ' each component editor page to display. Protected Overrides Function GetComponentEditorPages() As Type() Return New Type() {GetType(ExampleComponentEditorPage), GetType(ExampleComponentEditorPage)} End Function ' This method override returns the index of the page to display when the ' component editor is first displayed. Protected Overrides Function GetInitialComponentEditorPageIndex() As Integer Return 1 End Function Public Overloads Overrides Function EditComponent(ByVal context As System.ComponentModel.ITypeDescriptorContext, ByVal component As Object) As Boolean End Function End Class ' This example component editor page type provides an example ' ComponentEditorPage implementation. Friend Class ExampleComponentEditorPage Inherits System.Windows.Forms.Design.ComponentEditorPage Private l1 As Label Private b1 As Button Private pg1 As PropertyGrid ' Base64-encoded serialized image data for the required component editor page icon. Private icondata As String = "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" Public Sub New() ' Initialize the page, which inherits from Panel, and its controls. Me.Size = New Size(400, 250) Me.Icon = DeserializeIconFromBase64Text(icondata) Me.Text = "Example Page" b1 = New Button b1.Size = New Size(200, 20) b1.Location = New Point(200, 0) b1.Text = "Set a random background color" AddHandler b1.Click, AddressOf Me.randomBackColor Me.Controls.Add(b1) l1 = New Label l1.Size = New Size(190, 20) l1.Location = New Point(4, 2) l1.Text = "Example Component Editor Page" Me.Controls.Add(l1) pg1 = New PropertyGrid pg1.Size = New Size(400, 280) pg1.Location = New Point(0, 30) Me.Controls.Add(pg1) End Sub ' This method indicates that the Help button should be enabled for this ' component editor page. Public Overrides Function SupportsHelp() As Boolean Return True End Function ' This method is called when the Help button for this component editor page is pressed. ' This implementation uses the IHelpService to show the Help topic for a sample keyword. Public Overrides Sub ShowHelp() ' The GetSelectedComponent method of a ComponentEditorPage retrieves the ' IComponent associated with the WindowsFormsComponentEditor. Dim selectedComponent As IComponent = Me.GetSelectedComponent() ' Retrieve the Site of the component, and return if null. Dim componentSite As ISite = selectedComponent.Site If componentSite Is Nothing Then Return End If ' Acquire the IHelpService to display a help topic using a indexed keyword lookup. Dim helpService As IHelpService = CType(componentSite.GetService(GetType(IHelpService)), IHelpService) If (helpService IsNot Nothing) Then helpService.ShowHelpFromKeyword("System.Windows.Forms.ComboBox") End If End Sub ' The LoadComponent method is raised when the ComponentEditorPage is displayed. Protected Overrides Sub LoadComponent() Me.pg1.SelectedObject = Me.Component End Sub ' The SaveComponent method is raised when the WindowsFormsComponentEditor is closing ' or the current ComponentEditorPage is closing. Protected Overrides Sub SaveComponent() End Sub ' If the associated component is a Control, this method sets the BackColor to a random color. ' This method is invoked by the button on this ComponentEditorPage. Private Sub randomBackColor(ByVal sender As Object, ByVal e As EventArgs) If GetType(System.Windows.Forms.Control).IsAssignableFrom(CType(Me.Component, Object).GetType()) Then ' Sets the background color of the Control associated with the ' WindowsFormsComponentEditor to a random color. Dim rnd As New Random CType(Me.Component, System.Windows.Forms.Control).BackColor = Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255)) pg1.Refresh() End If End Sub ' This method can be used to retrieve an Icon from a block ' of Base64-encoded text. Private Function DeserializeIconFromBase64Text(ByVal [text] As String) As icon Dim img As Icon = Nothing Dim memBytes As Byte() = Convert.FromBase64String([text]) Dim formatter As New BinaryFormatter Dim stream As New MemoryStream(memBytes) img = CType(formatter.Deserialize(stream), Icon) stream.Close() Return img End Function End Class ' This example control is associated with the ExampleComponentEditor ' through the following EditorAttribute. <EditorAttribute(GetType(ExampleComponentEditor), GetType(ComponentEditor))> _ Public Class ExampleUserControl Inherits System.Windows.Forms.UserControl End Class
System.ComponentModel.ComponentEditor
System.Windows.Forms.Design.WindowsFormsComponentEditor
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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