ToolboxItem Class

Definition

Namespace:

System.Drawing.Design

Assembly:

System.Windows.Forms.Design.dll

Provides a base implementation of a toolbox item.

public ref class ToolboxItem : System::Runtime::Serialization::ISerializable

public class ToolboxItem : System.Runtime.Serialization.ISerializable

type ToolboxItem = class
    interface ISerializable

Public Class ToolboxItem
Implements ISerializable

Inheritance

Object

ToolboxItem

Derived

System.Web.UI.Design.WebControlToolboxItem

System.Workflow.ComponentModel.Design.ActivityToolboxItem

Implements

ISerializable

Examples

The following code example provides a component that uses the IToolboxService interface to add a text data format handler, or ToolboxItemCreatorCallback, to the toolbox. The data creator callback delegate passes any text data pasted to the toolbox and dragged onto a form to a custom ToolboxItem that creates a TextBox containing the text.

#using <System.Windows.Forms.dll>
#using <System.Drawing.dll>
#using <System.dll>

using namespace System;
using namespace System::ComponentModel;
using namespace System::ComponentModel::Design;
using namespace System::Drawing;
using namespace System::Drawing::Design;
using namespace System::Windows::Forms;
using namespace System::Security::Permissions;

namespace TextDataTextBoxComponent
{
   // Custom toolbox item creates a TextBox and sets its Text property
   // to the constructor-specified text.
   [PermissionSetAttribute(SecurityAction::Demand, Name="FullTrust")]
   public ref class TextToolboxItem: public ToolboxItem
   {
   private:
      String^ text;
      delegate void SetTextMethodHandler( Control^ c, String^ text );

   public:
      TextToolboxItem( String^ text )
         : ToolboxItem()
      {
         this->text = text;
      }

   protected:

      // ToolboxItem::CreateComponentsCore  to create the TextBox
      // and link a method to set its Text property.

      virtual array<IComponent^>^ CreateComponentsCore( IDesignerHost^ host ) override
      {
         TextBox^ textbox = dynamic_cast<TextBox^>(host->CreateComponent( TextBox::typeid ));
         
         // Because the designer resets the text of the textbox, use
         // a SetTextMethodHandler to set the text to the value of
         // the text data.
         Control^ c = dynamic_cast<Control^>(host->RootComponent);
         array<Object^>^temp0 = {textbox,text};
         c->BeginInvoke( gcnew SetTextMethodHandler( this, &TextToolboxItem::OnSetText ), temp0 );
         array<IComponent^>^temp1 = {textbox};
         return temp1;
      }

   private:

      // Method to set the text property of a TextBox after it is initialized.
      void OnSetText( Control^ c, String^ text )
      {
         c->Text = text;
      }

   };


   // Component that adds a "Text" data format ToolboxItemCreatorCallback 
    // to the Toolbox. This component uses a custom ToolboxItem that 
    // creates a TextBox containing the text data.
   public ref class TextDataTextBoxComponent: public Component
   {
   private:
      bool creatorAdded;
      IToolboxService^ ts;

   public:
      TextDataTextBoxComponent()
      {
         creatorAdded = false;
      }


      property System::ComponentModel::ISite^ Site 
      {
         // ISite to register TextBox creator
         virtual System::ComponentModel::ISite^ get() override
         {
            return __super::Site;
         }

         virtual void set( System::ComponentModel::ISite^ value ) override
         {
            if ( value != nullptr )
            {
               __super::Site = value;
               if (  !creatorAdded )
                              AddTextTextBoxCreator();
            }
            else
            {
               if ( creatorAdded )
                              RemoveTextTextBoxCreator();
               __super::Site = value;
            }
         }
      }

   private:

      // Adds a "Text" data format creator to the toolbox that creates
      // a textbox from a text fragment pasted to the toolbox.
      void AddTextTextBoxCreator()
      {
         ts = dynamic_cast<IToolboxService^>(GetService( IToolboxService::typeid ));
         if ( ts != nullptr )
         {
            ToolboxItemCreatorCallback^ textCreator = 
                gcnew ToolboxItemCreatorCallback( 
                this, 
                &TextDataTextBoxComponent::CreateTextBoxForText );
            try
            {
               ts->AddCreator( 
                   textCreator, 
                   "Text", 
                   dynamic_cast<IDesignerHost^>(GetService( IDesignerHost::typeid )) );
               creatorAdded = true;
            }
            catch ( Exception^ ex ) 
            {
               MessageBox::Show( ex->ToString(), "Exception Information" );
            }
         }
      }


      // Removes any "Text" data format creator from the toolbox.
      void RemoveTextTextBoxCreator()
      {
         if ( ts != nullptr )
         {
            ts->RemoveCreator( 
                "Text", 
                dynamic_cast<IDesignerHost^>(GetService( IDesignerHost::typeid )) );
            creatorAdded = false;
         }
      }


      // ToolboxItemCreatorCallback delegate format method to create
      // the toolbox item.
      ToolboxItem^ CreateTextBoxForText( Object^ serializedObject, String^ format )
      {
        IDataObject^ o = gcnew DataObject(dynamic_cast<IDataObject^>(serializedObject));

        if( o->GetDataPresent("System::String", true) )
        {
            String^ toolboxText = dynamic_cast<String^>(o->GetData( "System::String", true ));
           return( gcnew TextToolboxItem( toolboxText ));
        }

        return nullptr;
      }

   public:
      ~TextDataTextBoxComponent()
      {
         if ( creatorAdded )
                  RemoveTextTextBoxCreator();
      }
   };
}

using System;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Drawing;
using System.Drawing.Design;
using System.Security.Permissions;
using System.Windows.Forms;

namespace TextDataTextBoxComponent
{
    // Component that adds a "Text" data format ToolboxItemCreatorCallback 
    // to the Toolbox. This component uses a custom ToolboxItem that 
    // creates a TextBox containing the text data.
    public class TextDataTextBoxComponent : Component
    {
        private bool creatorAdded = false;
        private IToolboxService ts;

        public TextDataTextBoxComponent()
        {                     
        }

        // ISite override to register TextBox creator
        public override System.ComponentModel.ISite Site
        {
            get
            {
                return base.Site;
            }
            set
            {
                if( value != null )
                {                    
                    base.Site = value;

                    if (!creatorAdded)
                    {
                        AddTextTextBoxCreator();
                    }
                }
                else
                {
                    if (creatorAdded)
                    {
                        RemoveTextTextBoxCreator();
                    }

                    base.Site = value;             
                }
            }
        }

        // Adds a "Text" data format creator to the toolbox that creates 
        // a textbox from a text fragment pasted to the toolbox.
        private void AddTextTextBoxCreator()
        {
            ts = (IToolboxService)GetService(typeof(IToolboxService));

            if (ts != null) 
            {
                ToolboxItemCreatorCallback textCreator = 
                    new ToolboxItemCreatorCallback(this.CreateTextBoxForText);

                try
                {
                    ts.AddCreator(
                        textCreator, 
                        "Text", 
                        (IDesignerHost)GetService(typeof(IDesignerHost)));

                    creatorAdded = true;
                }
                catch(Exception ex)
                {
                    MessageBox.Show(
                        ex.ToString(), 
                        "Exception Information");
                }                
            }
        }

        // Removes any "Text" data format creator from the toolbox.
        private void RemoveTextTextBoxCreator()
        {
            if (ts != null)             
            {
                ts.RemoveCreator(
                    "Text", 
                    (IDesignerHost)GetService(typeof(IDesignerHost)));            

                creatorAdded = false;
            }
        }

        // ToolboxItemCreatorCallback delegate format method to create 
        // the toolbox item.
        private ToolboxItem CreateTextBoxForText(
            object serializedObject, 
            string format)
        {
            DataObject o = new DataObject((IDataObject)serializedObject);

            string[] formats = o.GetFormats();

            if (o.GetDataPresent("System.String", true))
            {
                string toolboxText = (string)(o.GetData("System.String", true));
                return (new TextToolboxItem(toolboxText));
            }

            return null;
        }

        protected override void Dispose(bool disposing)
        {
            if (creatorAdded)
            {
                RemoveTextTextBoxCreator();
            }
        }        
    }

    // Custom toolbox item creates a TextBox and sets its Text property
    // to the constructor-specified text.
    public class TextToolboxItem : ToolboxItem
    {
        private string text;
        private delegate void SetTextMethodHandler(Control c, string text);

        public TextToolboxItem(string text) : base()
        {
            this.text = text;
        }

        // ToolboxItem.CreateComponentsCore override to create the TextBox 
        // and link a method to set its Text property.
        protected override IComponent[] CreateComponentsCore(IDesignerHost host)
        {
            System.Windows.Forms.TextBox textbox = 
                (TextBox)host.CreateComponent(typeof(TextBox));
                
            // Because the designer resets the text of the textbox, use 
            // a SetTextMethodHandler to set the text to the value of 
            // the text data.
            Control c = host.RootComponent as Control;
            c.BeginInvoke(
                new SetTextMethodHandler(OnSetText), 
                new object[] {textbox, text});
           
            return new System.ComponentModel.IComponent[] { textbox };
        }        

        // Method to set the text property of a TextBox after it is initialized.
        private void OnSetText(Control c, string text) 
        {
            c.Text = text;
        }
    }
}

Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Drawing
Imports System.Drawing.Design
Imports System.Security.Permissions
Imports System.Windows.Forms

' Component that adds a "Text" data format ToolboxItemCreatorCallback 
' to the Toolbox. This component uses a custom ToolboxItem that 
' creates a TextBox containing the text data.
<PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
Public Class TextDataTextBoxComponent
    Inherits System.ComponentModel.Component

    Private creatorAdded As Boolean = False
    Private ts As IToolboxService

    Public Sub New()
    End Sub

    ' ISite override to register TextBox creator
    Public Overrides Property Site() As System.ComponentModel.ISite
        Get
            Return MyBase.Site
        End Get
        Set(ByVal Value As System.ComponentModel.ISite)
            If (Value IsNot Nothing) Then
                MyBase.Site = Value
                If Not creatorAdded Then
                    AddTextTextBoxCreator()
                End If
            Else
                If creatorAdded Then
                    RemoveTextTextBoxCreator()
                End If
                MyBase.Site = Value
            End If
        End Set
    End Property

    ' Adds a "Text" data format creator to the toolbox that creates 
    ' a textbox from a text fragment pasted to the toolbox.
    Private Sub AddTextTextBoxCreator()
        ts = CType(GetService(GetType(IToolboxService)), IToolboxService)
        If (ts IsNot Nothing) Then
            Dim textCreator As _
            New ToolboxItemCreatorCallback(AddressOf Me.CreateTextBoxForText)
            Try
                ts.AddCreator( _
                textCreator, _
                "Text", _
                CType(GetService(GetType(IDesignerHost)), IDesignerHost))

                creatorAdded = True
            Catch ex As Exception
                MessageBox.Show(ex.ToString(), "Exception Information")
            End Try
        End If
    End Sub

    ' Removes any "Text" data format creator from the toolbox.
    Private Sub RemoveTextTextBoxCreator()
        If (ts IsNot Nothing) Then
            ts.RemoveCreator( _
            "Text", _
            CType(GetService(GetType(IDesignerHost)), IDesignerHost))
            creatorAdded = False
        End If
    End Sub

    ' ToolboxItemCreatorCallback delegate format method to create 
    ' the toolbox item.
    Private Function CreateTextBoxForText( _
    ByVal serializedObject As Object, _
    ByVal format As String) As ToolboxItem

        Dim o As New DataObject(CType(serializedObject, IDataObject))

        Dim formats As String() = o.GetFormats()

        If o.GetDataPresent("System.String", True) Then

            Return New TextToolboxItem(CStr(o.GetData("System.String", True)))

        End If

        Return Nothing
    End Function

    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If creatorAdded Then
            RemoveTextTextBoxCreator()
        End If
    End Sub

End Class

' Custom toolbox item creates a TextBox and sets its Text property
' to the constructor-specified text.
<PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
Public Class TextToolboxItem
    Inherits System.Drawing.Design.ToolboxItem

    Private [text] As String

    Delegate Sub SetTextMethodHandler( _
    ByVal c As Control, _
    ByVal [text] As String)

    Public Sub New(ByVal [text] As String)
        Me.text = [text]
    End Sub

    ' ToolboxItem.CreateComponentsCore override to create the TextBox 
    ' and link a method to set its Text property.
    <PermissionSetAttribute(SecurityAction.Demand, Name:="FullTrust")> _
    Protected Overrides Function CreateComponentsCore(ByVal host As IDesignerHost) As IComponent()
        Dim textbox As TextBox = CType(host.CreateComponent(GetType(TextBox)), TextBox)

        ' Because the designer resets the text of the textbox, use 
        ' a SetTextMethodHandler to set the text to the value of 
        ' the text data.
        Dim c As Control = host.RootComponent

        c.BeginInvoke( _
        New SetTextMethodHandler(AddressOf OnSetText), _
        New Object() {textbox, [text]})

        Return New System.ComponentModel.IComponent() {textbox}
    End Function

    ' Method to set the text property of a TextBox after it is initialized.
    Private Sub OnSetText(ByVal c As Control, ByVal [text] As String)
        c.Text = [text]
    End Sub

End Class

The following code example demonstrates the use of the ToolboxItem class as a base class for a custom toolbox item implementation.

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Drawing.Design;
using System.Data;
using System.Runtime.Serialization;
using System.Text;
using System.Windows.Forms;

namespace CustomToolboxItem
{
    public class Form1 : Form
    {
        private System.ComponentModel.IContainer components = null;
        private UserControl1 userControl11;
        private System.Windows.Forms.Label label1;

        public Form1()
        {
            InitializeComponent();
        }

        private void InitializeComponent()
        {
            this.label1 = new System.Windows.Forms.Label();
            this.userControl11 = new CustomToolboxItem.UserControl1();
            this.SuspendLayout();
            // 
            // label1
            // 
            this.label1.Location = new System.Drawing.Point(15, 16);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(265, 62);
            this.label1.TabIndex = 0;
            this.label1.Text = "Build the project and drop UserControl1 from the toolbox onto the form.";
            // 
            // userControl11
            // 
            this.userControl11.LabelText = "This is a custom user control.  The text you see here is provided by a custom too" +
                "lbox item when the user control is dropped on the form.";
            this.userControl11.Location = new System.Drawing.Point(74, 81);
            this.userControl11.Name = "userControl11";
            this.userControl11.Padding = new System.Windows.Forms.Padding(6);
            this.userControl11.Size = new System.Drawing.Size(150, 150);
            this.userControl11.TabIndex = 1;
            // 
            // Form1
            // 
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.userControl11);
            this.Controls.Add(this.label1);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);
        }

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

        static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new Form1());
        }
    }

    // Configure this user control to have a custom toolbox item.
    [ToolboxItem(typeof(MyToolboxItem))]
    public class UserControl1 : UserControl
    {
        private System.ComponentModel.IContainer components = null;
        private System.Windows.Forms.Label label1;

        public UserControl1()
        {
            InitializeComponent();
        }

        public string LabelText
        {
            get
            {
                return label1.Text;
            }
            set
            {
                label1.Text = value;
            }
        }

        private void InitializeComponent()
        {
            this.label1 = new System.Windows.Forms.Label();
            this.SuspendLayout();
            // 
            // label1
            // 
            this.label1.Dock = System.Windows.Forms.DockStyle.Fill;
            this.label1.Location = new System.Drawing.Point(6, 6);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(138, 138);
            this.label1.TabIndex = 0;
            this.label1.Text = "This is a custom user control.  " + 
                "The text you see here is provided by a custom toolbox" +
                " item when the user control is dropped on the form.\r\n";
            this.label1.TextAlign = 
                System.Drawing.ContentAlignment.MiddleCenter;
            // 
            // UserControl1
            // 
            this.Controls.Add(this.label1);
            this.Name = "UserControl1";
            this.Padding = new System.Windows.Forms.Padding(6);
            this.ResumeLayout(false);
        }

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

    // Toolbox items must be serializable.
    [Serializable]
    class MyToolboxItem : ToolboxItem
    {
        // The add components dialog in Visual Studio looks for a public
        // constructor that takes a type.
        public MyToolboxItem(Type toolType)
            : base(toolType)
        {
        }

        // And you must provide this special constructor for serialization.
        // If you add additional data to MyToolboxItem that you
        // want to serialize, you may override Deserialize and
        // Serialize methods to add that data.  
        MyToolboxItem(SerializationInfo info, StreamingContext context)
        {
            Deserialize(info, context);
        }

        // Let's override the creation code and pop up a dialog.
        protected override IComponent[] CreateComponentsCore(
            System.ComponentModel.Design.IDesignerHost host, 
            System.Collections.IDictionary defaultValues)
        {
            // Get the string we want to fill in the custom
            // user control.  If the user cancels out of the dialog,
            // return null or an empty array to signify that the 
            // tool creation was canceled.
            using (ToolboxItemDialog d = new ToolboxItemDialog())
            {
                if (d.ShowDialog() == DialogResult.OK)
                {
                    string text = d.CreationText;

                    IComponent[] comps =
                        base.CreateComponentsCore(host, defaultValues);
                    // comps will have a single component: our data type.
                    ((UserControl1)comps[0]).LabelText = text;
                    return comps;
                }
                else
                {
                    return null;
                }
            }
        }
    }

    public class ToolboxItemDialog : Form
    {
        private System.ComponentModel.IContainer components = null;
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.TextBox textBox1;
        private System.Windows.Forms.Button button1;
        private System.Windows.Forms.Button button2;

        public ToolboxItemDialog()
        {
            InitializeComponent();
        }

        private void InitializeComponent()
        {
            this.label1 = new System.Windows.Forms.Label();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.button1 = new System.Windows.Forms.Button();
            this.button2 = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // label1
            // 
            this.label1.Location = new System.Drawing.Point(10, 9);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(273, 43);
            this.label1.TabIndex = 0;
            this.label1.Text = "Enter the text you would like" + 
                " to have the user control populated with:";
            // 
            // textBox1
            // 
            this.textBox1.AutoSize = false;
            this.textBox1.Location = new System.Drawing.Point(10, 58);
            this.textBox1.Multiline = true;
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(270, 67);
            this.textBox1.TabIndex = 1;
            this.textBox1.Text = "This is a custom user control.  " + 
                "The text you see here is provided by a custom toolbox" +
                " item when the user control is dropped on the form.";
            // 
            // button1
            // 
            this.button1.DialogResult = System.Windows.Forms.DialogResult.OK;
            this.button1.Location = new System.Drawing.Point(124, 131);
            this.button1.Name = "button1";
            this.button1.TabIndex = 2;
            this.button1.Text = "OK";
            // 
            // button2
            // 
            this.button2.DialogResult = System.Windows.Forms.DialogResult.Cancel;
            this.button2.Location = new System.Drawing.Point(205, 131);
            this.button2.Name = "button2";
            this.button2.TabIndex = 3;
            this.button2.Text = "Cancel";
            // 
            // ToolboxItemDialog
            // 
            this.AcceptButton = this.button1;
            this.CancelButton = this.button2;
            this.ClientSize = new System.Drawing.Size(292, 162);
            this.ControlBox = false;
            this.Controls.Add(this.button2);
            this.Controls.Add(this.button1);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.label1);
            this.FormBorderStyle = 
                System.Windows.Forms.FormBorderStyle.FixedDialog;
            this.Name = "ToolboxItemDialog";
            this.Text = "ToolboxItemDialog";
            this.ResumeLayout(false);
        }

        public string CreationText
        {
            get
            {
                return textBox1.Text;
            }
        }

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

Imports System.Collections.Generic
Imports System.ComponentModel
Imports System.Drawing
Imports System.Drawing.Design
Imports System.Runtime.Serialization
Imports System.Text
Imports System.Windows.Forms



Public Class Form1
    Inherits Form
    Private components As System.ComponentModel.IContainer = Nothing
    Friend WithEvents UserControl11 As UserControl1
    Friend WithEvents label1 As System.Windows.Forms.Label

    Public Sub New() 
        InitializeComponent()
    End Sub
    
    
    Private Sub InitializeComponent() 
        Me.label1 = New System.Windows.Forms.Label
        Me.UserControl11 = New UserControl1
        Me.SuspendLayout()
        '
        'label1
        '
        Me.label1.Location = New System.Drawing.Point(15, 16)
        Me.label1.Name = "label1"
        Me.label1.Size = New System.Drawing.Size(265, 62)
        Me.label1.TabIndex = 0
        Me.label1.Text = "Build the project and drop UserControl1" + _
            " from the toolbox onto the form."
        '
        'UserControl11
        '
        Me.UserControl11.LabelText = "This is a custom user control.  " + _
            "The text you see here is provided by a custom too" + _
            "lbox item when the user control is dropped on the form."
        Me.UserControl11.Location = New System.Drawing.Point(74, 85)
        Me.UserControl11.Name = "UserControl11"
        Me.UserControl11.Padding = New System.Windows.Forms.Padding(6)
        Me.UserControl11.TabIndex = 1
        '
        'Form1
        '
        Me.ClientSize = New System.Drawing.Size(292, 266)
        Me.Controls.Add(Me.UserControl11)
        Me.Controls.Add(Me.label1)
        Me.Name = "Form1"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    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
    
    
    Shared Sub Main() 
        Application.EnableVisualStyles()
        Application.Run(New Form1())
    End Sub
End Class

' Configure this user control to have a custom toolbox item.
<ToolboxItem(GetType(MyToolboxItem))> _
Public Class UserControl1
    Inherits UserControl
    Private components As System.ComponentModel.IContainer = Nothing
    Private label1 As System.Windows.Forms.Label


    Public Sub New()
        InitializeComponent()
    End Sub


    Public Property LabelText() As String
        Get
            Return label1.Text
        End Get
        Set(ByVal value As String)
            label1.Text = Value
        End Set
    End Property


    Private Sub InitializeComponent()
        Me.label1 = New System.Windows.Forms.Label()
        Me.SuspendLayout()
        ' 
        ' label1
        ' 
        Me.label1.Dock = System.Windows.Forms.DockStyle.Fill
        Me.label1.Location = New System.Drawing.Point(6, 6)
        Me.label1.Name = "label1"
        Me.label1.Size = New System.Drawing.Size(138, 138)
        Me.label1.TabIndex = 0
        Me.label1.Text = "This is a custom user control.  " + _
            "The text you see here is provided by a custom toolbox" + _
            " item when the user control is dropped on the form." + _
            vbCr + vbLf
        Me.label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
        ' 
        ' UserControl1
        ' 
        Me.Controls.Add(label1)
        Me.Name = "UserControl1"
        Me.Padding = New System.Windows.Forms.Padding(6)
        Me.ResumeLayout(False)
    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
End Class

' Toolbox items must be serializable.
<Serializable()> _
Class MyToolboxItem
    Inherits ToolboxItem

    ' The add components dialog in Visual Studio looks for a public
    ' constructor that takes a type.
    Public Sub New(ByVal toolType As Type)
        MyBase.New(toolType)
    End Sub


    ' And you must provide this special constructor for serialization.
    ' If you add additional data to MyToolboxItem that you
    ' want to serialize, you may override Deserialize and
    ' Serialize methods to add that data.  
    Sub New(ByVal info As SerializationInfo, _
        ByVal context As StreamingContext)
        Deserialize(info, context)
    End Sub


    ' Let's override the creation code and pop up a dialog.
    Protected Overrides Function CreateComponentsCore( _
        ByVal host As System.ComponentModel.Design.IDesignerHost, _
        ByVal defaultValues As System.Collections.IDictionary) _
        As IComponent()
        ' Get the string we want to fill in the custom
        ' user control.  If the user cancels out of the dialog,
        ' return null or an empty array to signify that the 
        ' tool creation was canceled.
        Using d As New ToolboxItemDialog()
            If d.ShowDialog() = DialogResult.OK Then
                Dim [text] As String = d.CreationText
                Dim comps As IComponent() = _
                    MyBase.CreateComponentsCore(host, defaultValues)
                ' comps will have a single component: our data type.
                CType(comps(0), UserControl1).LabelText = [text]
                Return comps
            Else
                Return Nothing
            End If
        End Using
    End Function
End Class


Public Class ToolboxItemDialog
    Inherits Form
    Private components As System.ComponentModel.IContainer = Nothing
    Private label1 As System.Windows.Forms.Label
    Private textBox1 As System.Windows.Forms.TextBox
    Private button1 As System.Windows.Forms.Button
    Private button2 As System.Windows.Forms.Button
    
    
    Public Sub New() 
        InitializeComponent()
    End Sub
    
    Private Sub InitializeComponent() 
        Me.label1 = New System.Windows.Forms.Label()
        Me.textBox1 = New System.Windows.Forms.TextBox()
        Me.button1 = New System.Windows.Forms.Button()
        Me.button2 = New System.Windows.Forms.Button()
        Me.SuspendLayout()
        ' 
        ' label1
        ' 
        Me.label1.Location = New System.Drawing.Point(10, 9)
        Me.label1.Name = "label1"
        Me.label1.Size = New System.Drawing.Size(273, 43)
        Me.label1.TabIndex = 0
        Me.label1.Text = "Enter the text you would like" + _
            " to have the user control populated with:"
        ' 
        ' textBox1
        ' 
        Me.textBox1.AutoSize = False
        Me.textBox1.Location = New System.Drawing.Point(10, 58)
        Me.textBox1.Multiline = True
        Me.textBox1.Name = "textBox1"
        Me.textBox1.Size = New System.Drawing.Size(270, 67)
        Me.textBox1.TabIndex = 1
        Me.textBox1.Text = "This is a custom user control.  " + _
            "The text you see here is provided by a custom toolbox" + _
            " item when the user control is dropped on the form."
        ' 
        ' button1
        ' 
        Me.button1.DialogResult = System.Windows.Forms.DialogResult.OK
        Me.button1.Location = New System.Drawing.Point(124, 131)
        Me.button1.Name = "button1"
        Me.button1.TabIndex = 2
        Me.button1.Text = "OK"
        ' 
        ' button2
        ' 
        Me.button2.DialogResult = System.Windows.Forms.DialogResult.Cancel
        Me.button2.Location = New System.Drawing.Point(205, 131)
        Me.button2.Name = "button2"
        Me.button2.TabIndex = 3
        Me.button2.Text = "Cancel"
        ' 
        ' ToolboxItemDialog
        ' 
        Me.AcceptButton = Me.button1
        Me.CancelButton = Me.button2
        Me.ClientSize = New System.Drawing.Size(292, 162)
        Me.ControlBox = False
        Me.Controls.Add(button2)
        Me.Controls.Add(button1)
        Me.Controls.Add(textBox1)
        Me.Controls.Add(label1)
        Me.FormBorderStyle = _
            System.Windows.Forms.FormBorderStyle.FixedDialog
        Me.Name = "ToolboxItemDialog"
        Me.Text = "ToolboxItemDialog"
        Me.ResumeLayout(False)
    
    End Sub
    
    Public ReadOnly Property CreationText() As String 
        Get
            Return textBox1.Text
        End Get
    End Property
    
    
    Protected Overrides Sub Dispose(ByVal disposing As Boolean) 
        If disposing AndAlso (components IsNot Nothing) Then
            components.Dispose()
        End If
        MyBase.Dispose(disposing)
    
    End Sub
End Class

Remarks

ToolboxItem is a base class for toolbox items that can be displayed in the toolbox of a design-time environment. A toolbox item typically represents a component to create when invoked on a design mode document. The ToolboxItem class provides the methods and properties needed to provide the toolbox with the display properties for the toolbox item, to create a component or components when used, and to serialize and deserialize itself for persistence within the toolbox database.

An instance of the ToolboxItem class can be configured with a name, bitmap, and type to create, without creating a class that derives from ToolboxItem. The ToolboxItem class also provides a base class for custom toolbox item implementations. A custom ToolboxItem can create multiple components. To implement a custom toolbox item, you must derive from ToolboxItem and override the CreateComponentsCore, Serialize, and Deserialize methods.

The following properties and methods must be configured for a ToolboxItem to function correctly:

• The DisplayName property specifies the label for the toolbox item when displayed in a toolbox.

• The TypeName property specifies the fully qualified name of the type of the component that the item creates. If a derived class creates multiple components, the TypeName property may or may not be used, contingent on whether a CreateComponentsCore method override depends on the value of this property.

• The AssemblyName property specifies the assembly that contains the type of a component that the item creates.

• The Bitmap property optionally specifies a bitmap image to display next to the display name for the toolbox item in the toolbox.

• The Filter property optionally contains any ToolboxItemFilterAttribute objects that determine whether the toolbox item can be used on a particular component.

• The CreateComponentsCore method returns the component instance or instances to insert where this tool is used.

• The Serialize method saves the toolbox item to a specified SerializationInfo.

• The Deserialize method configures the toolbox item from the state information contained in the specified SerializationInfo.

• The Initialize method configures the toolbox item to create the specified type of component, if the CreateComponentsCore method has not been overridden to behave differently.

• The Locked property indicates whether the properties of the toolbox item can be changed. A toolbox item is typically locked after it is added to a toolbox.

• The Lock method locks a toolbox item.

• The CheckUnlocked method throws an exception if the Locked property is true.

Constructors

ToolboxItem()	Initializes a new instance of the ToolboxItem class.
ToolboxItem(Type)	Initializes a new instance of the ToolboxItem class that creates the specified type of component.

Properties

AssemblyName	Gets or sets the name of the assembly that contains the type or types that the toolbox item creates.
Bitmap	Gets or sets a bitmap to represent the toolbox item in the toolbox.
Company	Gets or sets the company name for this ToolboxItem.
ComponentType	Gets the component type for this ToolboxItem.
DependentAssemblies	Gets or sets the AssemblyName for the toolbox item.
Description	Gets or sets the description for this ToolboxItem.
DisplayName	Gets or sets the display name for the toolbox item.
Filter	Gets or sets the filter that determines whether the toolbox item can be used on a destination component.
IsTransient	Gets a value indicating whether the toolbox item is transient.
Locked	Gets a value indicating whether the ToolboxItem is currently locked.
OriginalBitmap	Gets or sets the original bitmap that will be used in the toolbox for this item.
Properties	Gets a dictionary of properties.
TypeName	Gets or sets the fully qualified name of the type of IComponent that the toolbox item creates when invoked.
Version	Gets the version for this ToolboxItem.

Methods

CheckUnlocked()	Throws an exception if the toolbox item is currently locked.
CreateComponents()	Creates the components that the toolbox item is configured to create.
CreateComponents(IDesignerHost, IDictionary)	Creates the components that the toolbox item is configured to create, using the specified designer host and default values.
CreateComponents(IDesignerHost)	Creates the components that the toolbox item is configured to create, using the specified designer host.
CreateComponentsCore(IDesignerHost, IDictionary)	Creates an array of components when the toolbox item is invoked.
CreateComponentsCore(IDesignerHost)	Creates a component or an array of components when the toolbox item is invoked.
Deserialize(SerializationInfo, StreamingContext)	Loads the state of the toolbox item from the specified serialization information object.
Equals(Object)	Determines whether two ToolboxItem instances are equal.
FilterPropertyValue(String, Object)	Filters a property value before returning it.
GetHashCode()	Returns the hash code for this instance.
GetType()	Gets the Type of the current instance. (Inherited from Object)
GetType(IDesignerHost, AssemblyName, String, Boolean)	Creates an instance of the specified type, optionally using a specified designer host and assembly name.
GetType(IDesignerHost)	Enables access to the type associated with the toolbox item.
Initialize(Type)	Initializes the current toolbox item with the specified type to create.
Lock()	Locks the toolbox item and prevents changes to its properties.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
OnComponentsCreated(ToolboxComponentsCreatedEventArgs)	Raises the ComponentsCreated event.
OnComponentsCreating(ToolboxComponentsCreatingEventArgs)	Raises the ComponentsCreating event.
Serialize(SerializationInfo, StreamingContext)	Saves the state of the toolbox item to the specified serialization information object.
ToString()	Returns a String that represents the current ToolboxItem.
ValidatePropertyType(String, Object, Type, Boolean)	Validates that an object is of a given type.
ValidatePropertyValue(String, Object)	Validates a property before it is assigned to the property dictionary.

Events

ComponentsCreated	Occurs immediately after components are created.
ComponentsCreating	Occurs when components are about to be created.

Explicit Interface Implementations

ISerializable.GetObjectData(SerializationInfo, StreamingContext)

For a description of this member, see the GetObjectData(SerializationInfo, StreamingContext) method.

See also

• ToolboxItemFilterAttribute
• ToolboxItemAttribute
• IToolboxService
• IToolboxUser
• ToolboxComponentsCreatedEventArgs
• ToolboxComponentsCreatedEventHandler