ITypeDescriptorFilterService Interfaccia
Definizione
Importante
Alcune informazioni sono relative alla release non definitiva del prodotto, che potrebbe subire modifiche significative prima della release definitiva. Microsoft non riconosce alcuna garanzia, espressa o implicita, in merito alle informazioni qui fornite.
Fornisce un'interfaccia per modificare l'insieme dei descrittori di membro per un componente in modalità progettazione.
public interface class ITypeDescriptorFilterService
public interface ITypeDescriptorFilterService
type ITypeDescriptorFilterService = interface
Public Interface ITypeDescriptorFilterService
- Derivato
Esempio
L'esempio di codice seguente illustra una finestra di progettazione che usa ITypeDescriptorFilterService per filtrare la raccolta di attributi di qualsiasi nuovo o esistente Button per aggiungere un attributo di progettazione per una nuova finestra di progettazione prima di caricare o ricaricare la finestra di progettazione per il pulsante.
Per usare l'esempio, aggiungere il codice a un progetto Windows Forms e caricare i componenti dalla libreria di classi nella casella degli strumenti.
Vedere Anche procedura dettagliata: Popolamento automatico della casella degli strumenti con componenti personalizzati.
Aggiungere alcuni pulsanti al modulo. Aggiungere un oggetto ButtonDesignerFilterComponent
al modulo e verrà visualizzato nella barra dei componenti. Verrà ButtonDesignerFilterComponent
aggiunto un ButtonDesignerFilterService
oggetto , che implementa ITypeDescriptorFilterService, come provider di servizi in modalità di progettazione. Gli oggetti esistenti o nuovi Button nel modulo inizieranno il ciclo dei colori dopo che la ButtonDesignerFilterService
finestra di progettazione sostituisce la finestra di progettazione per ogni pulsante esistente e nuovo con un ColorCycleButtonDesigner
oggetto . I pulsanti verranno ciclicamente quando si sposta il puntatore del mouse su di essi, e in alternativa continuare il ciclismo o reimpostare lo sfondo e i colori di primo piano sugli MouseLeave
eventi. I nuovi Button oggetti verranno assegnati tramite il FilterAttributesColorCycleButtonDesigner
metodo dell'oggetto ButtonDesignerFilterService
caricato, fino a quando non ButtonDesignerFilterComponent
viene eliminato e sostituisce l'oggetto originaleITypeDescriptorFilterService. La ColorCycleButton
classe in questo esempio è associata Button a un ColorCycleButtonDesigner
oggetto .
#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>
#using <System.Design.dll>
#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::ComponentModel::Design::Serialization;
using namespace System::Drawing;
using namespace System::Reflection;
using namespace System::Timers;
using namespace System::Windows::Forms;
using namespace System::Windows::Forms::Design;
// Designer for a Button control which cycles the background color.
public ref class ColorCycleButtonDesigner: public System::Windows::Forms::Design::ControlDesigner
{
private:
System::Windows::Forms::Timer^ timer1;
Color initial_bcolor;
Color initial_fcolor;
int r;
int g;
int b;
bool ru;
bool gu;
bool bu;
bool continue_;
public:
ColorCycleButtonDesigner()
{
timer1 = gcnew System::Windows::Forms::Timer;
timer1->Interval = 50;
timer1->Tick += gcnew EventHandler( this, &ColorCycleButtonDesigner::Elapsed );
ru = true;
gu = false;
bu = true;
continue_ = false;
timer1->Start();
}
private:
void Elapsed( Object^ /*sender*/, EventArgs^ /*e*/ )
{
this->Control->BackColor = Color::FromArgb( r % 255, g % 255, b % 255 );
this->Control->Refresh();
// Updates color.
if ( ru )
r += 10;
else
if ( r > 10 )
r -= 10;
if ( gu )
g += 10;
else
if ( g > 10 )
g -= 10;
if ( bu )
b += 10;
else
if ( b > 10 )
b -= 10;
// Randomly switches direction of color component values.
Random^ rand = gcnew Random;
for ( int i = 0; i < 4; i++ )
switch ( rand->Next( 0, 2 ) )
{
case 0:
if ( ru )
ru = false;
else
ru = true;
break;
case 1:
if ( gu )
gu = false;
else
gu = true;
break;
case 2:
if ( bu )
bu = false;
else
bu = true;
break;
}
this->Control->ForeColor = Color::FromArgb( (this->Control->BackColor.R + 128) % 255, (this->Control->BackColor.G + 128) % 255, (this->Control->BackColor.B + 128) % 255 );
}
protected:
virtual void OnMouseEnter() override
{
if ( !timer1->Enabled )
{
initial_bcolor = this->Control->BackColor;
initial_fcolor = this->Control->ForeColor;
r = initial_bcolor.R;
g = initial_bcolor.G;
b = initial_bcolor.B;
timer1->Start();
}
}
virtual void OnMouseLeave() override
{
if ( !continue_ )
{
continue_ = true;
timer1->Stop();
}
else
continue_ = false;
this->Control->BackColor = initial_bcolor;
this->Control->ForeColor = initial_fcolor;
}
public:
~ColorCycleButtonDesigner()
{
timer1->Stop();
this->Control->BackColor = initial_bcolor;
this->Control->ForeColor = initial_fcolor;
}
};
// Provides a TypeDescriptorFilterService to add the
// ColorCycleButtonDesigner using a DesignerAttribute.
public ref class ButtonDesignerFilterService: public System::ComponentModel::Design::ITypeDescriptorFilterService
{
public:
ITypeDescriptorFilterService^ oldService;
ButtonDesignerFilterService(){}
ButtonDesignerFilterService( ITypeDescriptorFilterService^ oldService_ )
{
// Stores any previous ITypeDescriptorFilterService to implement service chaining.
this->oldService = oldService_;
}
virtual bool FilterAttributes( System::ComponentModel::IComponent^ component, System::Collections::IDictionary^ attributes )
{
if ( oldService != nullptr )
oldService->FilterAttributes( component, attributes );
// Creates a designer attribute to compare its TypeID with the TypeID of existing attributes of the component.
DesignerAttribute^ da = gcnew DesignerAttribute( ColorCycleButtonDesigner::typeid );
// Adds the designer attribute if the attribute collection does not contain a DesignerAttribute of the same TypeID.
if ( dynamic_cast<System::Windows::Forms::Button^>(component) && attributes->Contains( da->TypeId ) )
attributes[ da->TypeId ] = da;
return true;
}
virtual bool FilterEvents( System::ComponentModel::IComponent^ component, System::Collections::IDictionary^ events )
{
if ( oldService != nullptr )
oldService->FilterEvents( component, events );
return true;
}
virtual bool FilterProperties( System::ComponentModel::IComponent^ component, System::Collections::IDictionary^ properties )
{
if ( oldService != nullptr )
oldService->FilterProperties( component, properties );
return true;
}
};
// System.Windows.Forms.Button associated with the ColorCycleButtonDesigner.
[Designer(ColorCycleButtonDesigner::typeid)]
public ref class ColorCycleButton: public System::Windows::Forms::Button
{
public:
ColorCycleButton(){}
};
// Provides a designer that can add a ColorCycleButtonDesigner to each
// button in a design time project using the ButtonDesignerFilterService
// ITypeDescriptorFilterService.
public ref class ButtonDesignerFilterComponentDesigner: public System::ComponentModel::Design::ComponentDesigner
{
private:
// Indicates whether the service has been loaded.
bool serviceloaded;
// Stores any old ITypeDescriptorFilterService to restore later.
ITypeDescriptorFilterService^ oldservice;
public:
ButtonDesignerFilterComponentDesigner()
{
serviceloaded = false;
}
// Loads the new ITypeDescriptorFilterService and reloads the
// designers for each button.
virtual void Initialize( System::ComponentModel::IComponent^ component ) override
{
ComponentDesigner::Initialize( component );
// Loads the custom service if it has not been loaded already
LoadService();
// Build list of buttons from Container.Components.
ArrayList^ buttons = gcnew ArrayList;
IEnumerator^ myEnum = this->Component->Site->Container->Components->GetEnumerator();
while ( myEnum->MoveNext() )
{
IComponent^ c = safe_cast<IComponent^>(myEnum->Current);
if ( c->GetType() == System::Windows::Forms::Button::typeid )
buttons->Add( dynamic_cast<System::Windows::Forms::Button^>(c) );
}
if ( buttons->Count > 0 )
{
// Tests each Button for an existing
// ColorCycleButtonDesigner;
// if it has no designer of type
// ColorCycleButtonDesigner, adds a designer.
IEnumerator^ myEnum1 = buttons->GetEnumerator();
while ( myEnum1->MoveNext() )
{
Button^ b = safe_cast<Button^>(myEnum1->Current);
bool loaddesigner = true;
// Gets the attributes for each button.
AttributeCollection^ ac = TypeDescriptor::GetAttributes( b );
for ( int i = 0; i < ac->Count; i++ )
{
// If designer attribute is not for a
// ColorCycleButtonDesigner, adds a new
// ColorCycleButtonDesigner.
if ( dynamic_cast<DesignerAttribute^>(ac[ i ]) )
{
DesignerAttribute^ da = dynamic_cast<DesignerAttribute^>(ac[ i ]);
if ( da->DesignerTypeName->Substring( da->DesignerTypeName->LastIndexOf( "." ) + 1 )->Equals( "ColorCycleButtonDesigner" ) )
loaddesigner = false;
}
}
if ( loaddesigner )
{
// Saves the button location so that it
// can be repositioned.
Point p = b->Location;
// Gets an IMenuCommandService to cut and
// paste control in order to register with
// selection and movement interface after
// designer is changed without reloading.
IMenuCommandService^ imcs = dynamic_cast<IMenuCommandService^>(this->GetService( IMenuCommandService::typeid ));
if ( imcs == nullptr )
throw gcnew Exception( "Could not obtain IMenuCommandService interface." );
// Gets an ISelectionService to select the
// button so that it can be cut and pasted.
ISelectionService^ iss = dynamic_cast<ISelectionService^>(this->GetService( ISelectionService::typeid ));
if ( iss == nullptr )
throw gcnew Exception( "Could not obtain ISelectionService interface." );
array<IComponent^>^temp0 = {b};
iss->SetSelectedComponents( dynamic_cast<ICollection^>(temp0), SelectionTypes::Normal );
// Invoke Cut and Paste.
imcs->GlobalInvoke( StandardCommands::Cut );
imcs->GlobalInvoke( StandardCommands::Paste );
// Regains reference to button from
// selection service.
System::Windows::Forms::Button^ b2 = dynamic_cast<System::Windows::Forms::Button^>(iss->PrimarySelection);
iss->SetSelectedComponents( nullptr );
// Refreshes TypeDescriptor properties of
// button to load new attributes from
// ButtonDesignerFilterService.
TypeDescriptor::Refresh( b2 );
b2->Location = p;
b2->Focus();
}
}
}
}
private:
// Loads a ButtonDesignerFilterService ITypeDescriptorFilterService
// to add ColorCycleButtonDesigner designers to each button.
void LoadService()
{
// If no custom ITypeDescriptorFilterService is loaded,
// loads it now.
if ( !serviceloaded )
{
// Stores the current ITypeDescriptorFilterService
// to restore later.
ITypeDescriptorFilterService^ tdfs = dynamic_cast<ITypeDescriptorFilterService^>(this->Component->Site->GetService( ITypeDescriptorFilterService::typeid ));
if ( tdfs != nullptr )
oldservice = tdfs;
// Retrieves an IDesignerHost interface to use to
// remove and add services.
IDesignerHost^ dh = dynamic_cast<IDesignerHost^>(this->Component->Site->GetService( IDesignerHost::typeid ));
if ( dh == nullptr )
throw gcnew Exception( "Could not obtain IDesignerHost interface." );
// Removes standard ITypeDescriptorFilterService.
dh->RemoveService( ITypeDescriptorFilterService::typeid );
// Adds new custom ITypeDescriptorFilterService.
dh->AddService( ITypeDescriptorFilterService::typeid, gcnew ButtonDesignerFilterService );
serviceloaded = true;
}
}
// Removes the custom service and reloads any stored,
// preexisting service.
void RemoveService()
{
IDesignerHost^ dh = dynamic_cast<IDesignerHost^>(this->GetService( IDesignerHost::typeid ));
if ( dh == nullptr )
throw gcnew Exception( "Could not obtain IDesignerHost interface." );
dh->RemoveService( ITypeDescriptorFilterService::typeid );
if ( oldservice != nullptr )
dh->AddService( ITypeDescriptorFilterService::typeid, oldservice );
serviceloaded = false;
}
public:
~ButtonDesignerFilterComponentDesigner()
{
if ( serviceloaded )
RemoveService();
}
};
// Component to host the ButtonDesignerFilterComponentDesigner that loads the
// ButtonDesignerFilterService ITypeDescriptorFilterService.
[Designer(ButtonDesignerFilterComponentDesigner::typeid)]
public ref class ButtonDesignerFilterComponent: public System::ComponentModel::Component
{
public:
ButtonDesignerFilterComponent( System::ComponentModel::IContainer^ container )
{
container->Add( this );
}
ButtonDesignerFilterComponent(){}
};
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.ComponentModel.Design.Serialization;
using System.Drawing;
using System.Reflection;
using System.Timers;
using System.Windows.Forms;
using System.Windows.Forms.Design;
namespace ITypeDescriptorFilterSample
{
// Component to host the ButtonDesignerFilterComponentDesigner that loads the
// ButtonDesignerFilterService ITypeDescriptorFilterService.
[Designer(typeof(ButtonDesignerFilterComponentDesigner))]
public class ButtonDesignerFilterComponent : System.ComponentModel.Component
{
public ButtonDesignerFilterComponent(System.ComponentModel.IContainer container)
{
container.Add(this);
}
public ButtonDesignerFilterComponent()
{}
}
// Provides a designer that can add a ColorCycleButtonDesigner to each
// button in a design time project using the ButtonDesignerFilterService
// ITypeDescriptorFilterService.
public class ButtonDesignerFilterComponentDesigner : System.ComponentModel.Design.ComponentDesigner
{
// Indicates whether the service has been loaded.
private bool serviceloaded = false;
// Stores any old ITypeDescriptorFilterService to restore later.
private ITypeDescriptorFilterService oldservice = null;
public ButtonDesignerFilterComponentDesigner()
{}
// Loads the new ITypeDescriptorFilterService and reloads the
// designers for each button.
public override void Initialize(System.ComponentModel.IComponent component)
{
base.Initialize(component);
// Loads the custom service if it has not been loaded already
LoadService();
// Build list of buttons from Container.Components.
ArrayList buttons = new ArrayList();
foreach(IComponent c in this.Component.Site.Container.Components)
if(c.GetType() == typeof(System.Windows.Forms.Button))
buttons.Add((System.Windows.Forms.Button)c);
if(buttons.Count > 0)
{
// Tests each Button for an existing
// ColorCycleButtonDesigner;
// if it has no designer of type
// ColorCycleButtonDesigner, adds a designer.
foreach(System.Windows.Forms.Button b in buttons)
{
bool loaddesigner = true;
// Gets the attributes for each button.
AttributeCollection ac = TypeDescriptor.GetAttributes(b);
for(int i=0; i<ac.Count; i++)
{
// If designer attribute is not for a
// ColorCycleButtonDesigner, adds a new
// ColorCycleButtonDesigner.
if( ac[i] is DesignerAttribute )
{
DesignerAttribute da = (DesignerAttribute)ac[i];
if( da.DesignerTypeName.Substring(da.DesignerTypeName.LastIndexOf(".")+1) == "ColorCycleButtonDesigner" )
loaddesigner = false;
}
}
if(loaddesigner)
{
// Saves the button location so that it
// can be repositioned.
Point p = b.Location;
// Gets an IMenuCommandService to cut and
// paste control in order to register with
// selection and movement interface after
// designer is changed without reloading.
IMenuCommandService imcs = (IMenuCommandService)this.GetService(typeof(IMenuCommandService));
if( imcs == null )
throw new Exception("Could not obtain IMenuCommandService interface.");
// Gets an ISelectionService to select the
// button so that it can be cut and pasted.
ISelectionService iss = (ISelectionService)this.GetService(typeof(ISelectionService));
if( iss == null)
throw new Exception("Could not obtain ISelectionService interface.");
iss.SetSelectedComponents(new IComponent[] { b }, SelectionTypes.Auto);
// Invoke Cut and Paste.
imcs.GlobalInvoke(StandardCommands.Cut);
imcs.GlobalInvoke(StandardCommands.Paste);
// Regains reference to button from
// selection service.
System.Windows.Forms.Button b2 = (System.Windows.Forms.Button)iss.PrimarySelection;
iss.SetSelectedComponents(null);
// Refreshes TypeDescriptor properties of
// button to load new attributes from
// ButtonDesignerFilterService.
TypeDescriptor.Refresh(b2);
b2.Location = p;
b2.Focus();
}
}
}
}
// Loads a ButtonDesignerFilterService ITypeDescriptorFilterService
// to add ColorCycleButtonDesigner designers to each button.
private void LoadService()
{
// If no custom ITypeDescriptorFilterService is loaded,
// loads it now.
if(!serviceloaded)
{
// Stores the current ITypeDescriptorFilterService
// to restore later.
ITypeDescriptorFilterService tdfs = (ITypeDescriptorFilterService)this.Component.Site.GetService(typeof(ITypeDescriptorFilterService));
if( tdfs != null )
oldservice = tdfs;
// Retrieves an IDesignerHost interface to use to
// remove and add services.
IDesignerHost dh = (IDesignerHost)this.Component.Site.GetService(typeof(IDesignerHost));
if( dh == null )
throw new Exception("Could not obtain IDesignerHost interface.");
// Removes standard ITypeDescriptorFilterService.
dh.RemoveService(typeof(ITypeDescriptorFilterService));
// Adds new custom ITypeDescriptorFilterService.
dh.AddService(typeof(ITypeDescriptorFilterService), new ButtonDesignerFilterService());
serviceloaded = true;
}
}
// Removes the custom service and reloads any stored,
// preexisting service.
private void RemoveService()
{
IDesignerHost dh = (IDesignerHost)this.GetService(typeof(IDesignerHost));
if( dh == null )
throw new Exception("Could not obtain IDesignerHost interface.");
dh.RemoveService(typeof(ITypeDescriptorFilterService));
if( oldservice != null )
dh.AddService(typeof(ITypeDescriptorFilterService), oldservice);
serviceloaded = false;
}
protected override void Dispose(bool disposing)
{
if(serviceloaded)
RemoveService();
}
}
// Provides a TypeDescriptorFilterService to add the
// ColorCycleButtonDesigner using a DesignerAttribute.
public class ButtonDesignerFilterService : System.ComponentModel.Design.ITypeDescriptorFilterService
{
public ITypeDescriptorFilterService oldService = null;
public ButtonDesignerFilterService()
{}
public ButtonDesignerFilterService(ITypeDescriptorFilterService oldService_)
{
// Stores any previous ITypeDescriptorFilterService to implement service chaining.
this.oldService = oldService_;
}
public bool FilterAttributes(System.ComponentModel.IComponent component, System.Collections.IDictionary attributes)
{
if(oldService != null)
oldService.FilterAttributes(component, attributes);
// Creates a designer attribute to compare its TypeID with the TypeID of existing attributes of the component.
DesignerAttribute da = new DesignerAttribute(typeof(ColorCycleButtonDesigner));
// Adds the designer attribute if the attribute collection does not contain a DesignerAttribute of the same TypeID.
if(component is System.Windows.Forms.Button && attributes.Contains(da.TypeId))
attributes[da.TypeId]=da;
return true;
}
public bool FilterEvents(System.ComponentModel.IComponent component, System.Collections.IDictionary events)
{
if(oldService != null)
oldService.FilterEvents(component, events);
return true;
}
public bool FilterProperties(System.ComponentModel.IComponent component, System.Collections.IDictionary properties)
{
if(oldService != null)
oldService.FilterProperties(component, properties);
return true;
}
}
// Designer for a Button control which cycles the background color.
public class ColorCycleButtonDesigner : System.Windows.Forms.Design.ControlDesigner
{
private System.Windows.Forms.Timer timer1;
private Color initial_bcolor, initial_fcolor;
private int r, g, b;
private bool ru, gu, bu, continue_;
public ColorCycleButtonDesigner()
{
timer1 = new System.Windows.Forms.Timer();
timer1.Interval = 50;
timer1.Tick += new EventHandler(this.Elapsed);
ru = true;
gu = false;
bu = true;
continue_ = false;
timer1.Start();
}
private void Elapsed(object sender, EventArgs e)
{
this.Control.BackColor = Color.FromArgb(r%255, g%255, b%255);
this.Control.Refresh();
// Updates color.
if(ru)
r+=10;
else if(r>10)
r-=10;
if(gu)
g+=10;
else if(g>10)
g-=10;
if(bu)
b+=10;
else if(b>10)
b-=10;
// Randomly switches direction of color component values.
Random rand = new Random();
for(int i=0; i<4; i++)
switch(rand.Next(0, 2))
{
case 0:
if(ru)
ru=false;
else
ru=true;
break;
case 1:
if(gu)
gu=false;
else
gu=true;
break;
case 2:
if(bu)
bu=false;
else
bu=true;
break;
}
this.Control.ForeColor = Color.FromArgb((this.Control.BackColor.R+128)%255, (this.Control.BackColor.G+128)%255, (this.Control.BackColor.B+128)%255);
}
protected override void OnMouseEnter()
{
if(!timer1.Enabled)
{
initial_bcolor = this.Control.BackColor;
initial_fcolor = this.Control.ForeColor;
r = initial_bcolor.R;
g = initial_bcolor.G;
b = initial_bcolor.B;
timer1.Start();
}
}
protected override void OnMouseLeave()
{
if(!continue_)
{
continue_ = true;
timer1.Stop();
}
else
{
continue_ = false;
}
this.Control.BackColor = initial_bcolor;
this.Control.ForeColor = initial_fcolor;
}
protected override void Dispose(bool disposing)
{
timer1.Stop();
this.Control.BackColor = initial_bcolor;
this.Control.ForeColor = initial_fcolor;
base.Dispose(disposing);
}
}
// System.Windows.Forms.Button associated with the ColorCycleButtonDesigner.
[Designer(typeof(ColorCycleButtonDesigner))]
public class ColorCycleButton : System.Windows.Forms.Button
{
public ColorCycleButton()
{}
}
}
Imports System.Collections
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.ComponentModel.Design.Serialization
Imports System.Drawing
Imports System.Reflection
Imports System.Timers
Imports System.Windows.Forms
Imports System.Windows.Forms.Design
Namespace ITypeDescriptorFilterSample
' Component to host the ButtonDesignerFilterComponentDesigner that loads the
' ButtonDesignerFilterService ITypeDescriptorFilterService.
<Designer(GetType(ButtonDesignerFilterComponentDesigner))> _
Public Class ButtonDesignerFilterComponent
Inherits System.ComponentModel.Component
Public Sub New(ByVal container As System.ComponentModel.IContainer)
container.Add(Me)
End Sub
Public Sub New()
End Sub
End Class
' Provides a designer that can add a ColorCycleButtonDesigner to each
' button in a design time project using the ButtonDesignerFilterService
' ITypeDescriptorFilterService.
Public Class ButtonDesignerFilterComponentDesigner
Inherits System.ComponentModel.Design.ComponentDesigner
' Indicates whether the service has been loaded.
Private serviceloaded As Boolean = False
' Stores any old ITypeDescriptorFilterService to restore later.
Private oldservice As ITypeDescriptorFilterService = Nothing
Public Sub New()
End Sub
' Loads the new ITypeDescriptorFilterService and reloads the
' designers for each Button.
Public Overrides Sub Initialize(ByVal component As System.ComponentModel.IComponent)
MyBase.Initialize(component)
' Loads the custom service if it has not been loaded already.
LoadService()
' Build list of buttons from Container.Components.
Dim buttons As New ArrayList()
Dim c As IComponent
For Each c In Me.Component.Site.Container.Components
If TypeOf c Is System.Windows.Forms.Button Then
buttons.Add(CType(c, System.Windows.Forms.Button))
End If
Next c
If buttons.Count > 0 Then
' Tests each Button for an existing
' ColorCycleButtonDesigner;
' if it has no designer of type
' ColorCycleButtonDesigner, adds a designer.
Dim b As System.Windows.Forms.Button
For Each b In buttons
Dim loaddesigner As Boolean = True
' Gets the attributes for each button.
Dim ac As AttributeCollection = TypeDescriptor.GetAttributes(b)
Dim i As Integer
For i = 0 To ac.Count - 1
' If designer attribute is not for a
' ColorCycleButtonDesigner, adds a new
' ColorCycleButtonDesigner.
If TypeOf ac(i) Is DesignerAttribute Then
Dim da As DesignerAttribute = CType(ac(i), DesignerAttribute)
If da.DesignerTypeName.Substring((da.DesignerTypeName.LastIndexOf(".") + 1)) = "ColorCycleButtonDesigner" Then
loaddesigner = False
End If
End If
Next i
If loaddesigner Then
' Saves the button location so that it
' can be repositioned.
Dim p As Point = b.Location
' Gets an IMenuCommandService to cut and
' paste control in order to register with
' selection and movement interface after
' designer is changed without reloading.
Dim imcs As IMenuCommandService = CType(Me.GetService(GetType(IMenuCommandService)), IMenuCommandService)
If imcs Is Nothing Then
Throw New Exception("Could not obtain IMenuCommandService interface.")
End If
' Gets an ISelectionService to select the
' button so that it can be cut and pasted.
Dim iss As ISelectionService = CType(Me.GetService(GetType(ISelectionService)), ISelectionService)
If iss Is Nothing Then
Throw New Exception("Could not obtain ISelectionService interface.")
End If
iss.SetSelectedComponents(New IComponent() {b}, SelectionTypes.Auto)
' Invoke Cut and Paste.
imcs.GlobalInvoke(StandardCommands.Cut)
imcs.GlobalInvoke(StandardCommands.Paste)
' Regains reference to button from
' selection service.
Dim b2 As System.Windows.Forms.Button = CType(iss.PrimarySelection, System.Windows.Forms.Button)
iss.SetSelectedComponents(Nothing)
' Refreshes TypeDescriptor properties of
' button to load new attributes from
' ButtonDesignerFilterService.
TypeDescriptor.Refresh(b2)
b2.Location = p
b2.Focus()
End If
Next b
End If
End Sub
' Loads a ButtonDesignerFilterService ITypeDescriptorFilterService
' to add ColorCycleButtonDesigner designers to each button.
Private Sub LoadService()
' If no custom ITypeDescriptorFilterService is loaded,
' loads it now.
If Not serviceloaded Then
' Stores the current ITypeDescriptorFilterService
' to restore later.
Dim tdfs As ITypeDescriptorFilterService = CType(Me.Component.Site.GetService(GetType(ITypeDescriptorFilterService)), ITypeDescriptorFilterService)
If (tdfs IsNot Nothing) Then
oldservice = tdfs
End If
' Retrieves an IDesignerHost interface to use to
' remove and add services.
Dim dh As IDesignerHost = CType(Me.Component.Site.GetService(GetType(IDesignerHost)), IDesignerHost)
If dh Is Nothing Then
Throw New Exception("Could not obtain IDesignerHost interface.")
End If
' Removes the standard ITypeDescriptorFilterService.
dh.RemoveService(GetType(ITypeDescriptorFilterService))
' Adds the new custom ITypeDescriptorFilterService.
dh.AddService(GetType(ITypeDescriptorFilterService), New ButtonDesignerFilterService())
serviceloaded = True
End If
End Sub
' Removes the custom service and reloads any stored,
' preexisting service.
Private Sub RemoveService()
Dim dh As IDesignerHost = CType(Me.GetService(GetType(IDesignerHost)), IDesignerHost)
If dh Is Nothing Then
Throw New Exception("Could not obtain IDesignerHost interface.")
End If
dh.RemoveService(GetType(ITypeDescriptorFilterService))
If (oldservice IsNot Nothing) Then
dh.AddService(GetType(ITypeDescriptorFilterService), oldservice)
End If
serviceloaded = False
End Sub
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If serviceloaded Then
RemoveService()
End If
End Sub
End Class
' Provides a TypeDescriptorFilterService to add the
' ColorCycleButtonDesigner using a DesignerAttribute.
Public Class ButtonDesignerFilterService
Implements System.ComponentModel.Design.ITypeDescriptorFilterService
Public oldService As ITypeDescriptorFilterService = Nothing
Public Sub New()
End Sub
Public Sub New(ByVal oldService_ As ITypeDescriptorFilterService)
' Stores any previous ITypeDescriptorFilterService to implement service chaining.
Me.oldService = oldService_
End Sub
Public Function FilterAttributes(ByVal component As System.ComponentModel.IComponent, ByVal attributes As System.Collections.IDictionary) As Boolean Implements ITypeDescriptorFilterService.FilterAttributes
If (oldService IsNot Nothing) Then
oldService.FilterAttributes(component, attributes)
End If
' Creates a designer attribute to compare its TypeID with the TypeID of existing attributes of the component.
Dim da As New DesignerAttribute(GetType(ColorCycleButtonDesigner))
' Adds the designer attribute if the attribute collection does not contain a DesignerAttribute of the same TypeID.
If TypeOf component Is System.Windows.Forms.Button And attributes.Contains(da.TypeId) Then
attributes(da.TypeId) = da
End If
Return True
End Function
Public Function FilterEvents(ByVal component As System.ComponentModel.IComponent, ByVal events As System.Collections.IDictionary) As Boolean Implements ITypeDescriptorFilterService.FilterEvents
If (oldService IsNot Nothing) Then
oldService.FilterEvents(component, events)
End If
Return True
End Function
Public Function FilterProperties(ByVal component As System.ComponentModel.IComponent, ByVal properties As System.Collections.IDictionary) As Boolean Implements ITypeDescriptorFilterService.FilterProperties
If (oldService IsNot Nothing) Then
oldService.FilterProperties(component, properties)
End If
Return True
End Function
End Class
' Designer for a Button control which cycles the background color.
Public Class ColorCycleButtonDesigner
Inherits System.Windows.Forms.Design.ControlDesigner
Private timer1 As System.Windows.Forms.Timer
Private initial_bcolor, initial_fcolor As Color
Private r, g, b As Integer
Private ru, gu, bu, continue_ As Boolean
Public Sub New()
timer1 = New System.Windows.Forms.Timer()
timer1.Interval = 50
AddHandler timer1.Tick, AddressOf Me.Elapsed
ru = True
gu = False
bu = True
continue_ = False
timer1.Start()
End Sub
Private Sub Elapsed(ByVal sender As Object, ByVal e As EventArgs)
Me.Control.BackColor = Color.FromArgb(r Mod 255, g Mod 255, b Mod 255)
Me.Control.Refresh()
' Updates color.
If ru Then
r += 10
Else
If r > 10 Then
r -= 10
End If
End If
If gu Then
g += 10
Else
If g > 10 Then
g -= 10
End If
End If
If bu Then
b += 10
Else
If b > 10 Then
b -= 10
End If
End If
' Randomly switches direction of color component values.
Dim rand As New Random()
Dim i As Integer
For i = 0 To 3
Select Case rand.Next(0, 2)
Case 0
If ru Then
ru = False
Else
ru = True
End If
Case 1
If gu Then
gu = False
Else
gu = True
End If
Case 2
If bu Then
bu = False
Else
bu = True
End If
End Select
Next i
Me.Control.ForeColor = Color.FromArgb((Me.Control.BackColor.R + 128) Mod 255, (Me.Control.BackColor.G + 128) Mod 255, (Me.Control.BackColor.B + 128) Mod 255)
End Sub
Protected Overrides Sub OnMouseEnter()
If Not timer1.Enabled Then
initial_bcolor = Me.Control.BackColor
initial_fcolor = Me.Control.ForeColor
r = initial_bcolor.R
g = initial_bcolor.G
b = initial_bcolor.B
timer1.Start()
End If
End Sub
Protected Overrides Sub OnMouseLeave()
If Not continue_ Then
continue_ = True
timer1.Stop()
Else
continue_ = False
End If
Me.Control.BackColor = initial_bcolor
Me.Control.ForeColor = initial_fcolor
End Sub
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
timer1.Stop()
Me.Control.BackColor = initial_bcolor
Me.Control.ForeColor = initial_fcolor
MyBase.Dispose(disposing)
End Sub
End Class
' System.Windows.Forms.Button associated with the ColorCycleButtonDesigner.
<Designer(GetType(ColorCycleButtonDesigner))> _
Public Class ColorCycleButton
Inherits System.Windows.Forms.Button
Public Sub New()
End Sub
End Class
End Namespace
Commenti
L'interfaccia ITypeDescriptorFilterService fornisce un'interfaccia che consente di modificare le proprietà, gli eventi e gli attributi a livello di classe di un componente in fase di progettazione. Questa modifica si verifica tramite il set di descrittori forniti da un componente tramite .TypeDescriptor Il descrittore di tipo eseguirà una query sul sito di un componente per il ITypeDescriptorFilterService servizio e, se presente, il descrittore di tipo passerà tutti i metadati raccolti al servizio. Il servizio può quindi modificare i metadati aggiungendo, rimuovendo e modificando le caratteristiche esistenti del componente.
Ad esempio, le proprietà di un componente possono essere modificate tramite una chiamata al FilterProperties metodo . Il servizio filtro ottiene un dizionario contenente i nomi delle proprietà e i descrittori di proprietà di tipo PropertyDescriptor. Le modifiche vengono implementate usando la logica seguente.
Modifica | Implementazione |
---|---|
Rimozione | Eliminare la voce corrispondente nel dizionario. |
Addizione | Aggiungere la voce appropriata al dizionario. |
Alterazione | Chiamare i metodi descrittori delle proprietà esistenti, sostituire la voce descrittore della proprietà associata o sostituire l'intera coppia chiave/valore della proprietà nel dizionario. |
Il valore restituito di determina se questo set di FilterProperties proprietà è fisso. Se questo metodo restituisce true
, l'oggetto TypeDescriptor per questo componente può memorizzare nella cache i risultati. Questa cache viene mantenuta finché il componente non viene raccolto o viene chiamato il Refresh metodo del descrittore di tipo.
Note per gli implementatori
Per filtrare i descrittori membro esposti da un TypeDescriptoroggetto , implementare questa interfaccia in un componente e eseguire l'override rispettivamente dei FilterAttributes(IComponent, IDictionary)metodi , FilterEvents(IComponent, IDictionary)o FilterProperties(IComponent, IDictionary) di questa classe per filtrare attributi, eventi o proprietà.
Metodi
FilterAttributes(IComponent, IDictionary) |
Filtra gli attributi esposti da un componente tramite un oggetto TypeDescriptor. |
FilterEvents(IComponent, IDictionary) |
Filtra gli eventi esposti da un componente tramite un oggetto TypeDescriptor. |
FilterProperties(IComponent, IDictionary) |
Filtra le proprietà esposte da un componente tramite un oggetto TypeDescriptor. |