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ToolboxItemFilterType Enumeration

Defines identifiers used to indicate the type of filter that a ToolboxItemFilterAttribute uses.

Namespace: System.ComponentModel
Assembly: System (in system.dll)

'Declaration
Public Enumeration ToolboxItemFilterType
'Usage
Dim instance As ToolboxItemFilterType

public enum ToolboxItemFilterType
public enum ToolboxItemFilterType

 Member nameDescription
AllowIndicates that a toolbox item filter string is allowed, but not required. 
CustomIndicates that custom processing is required to determine whether to use a toolbox item filter string.  

This type of ToolboxItemFilterType is typically specified on a root designer class to indicate that the designer wishes to accept or reject a toolbox item through code. The designer must implement the GetToolSupported method of the IToolboxUser interface.

PreventIndicates that a toolbox item filter string is not allowed.  

If a designer and a component class both have a filter string and one has a ToolboxItemFilterType of Prevent, the toolbox item will not be available.

RequireIndicates that a toolbox item filter string must be present for a toolbox item to be enabled.  

For a toolbox item with a filter type of Require to be enabled, the designer and the component class must have a matching filter string. Additionally, neither the designer or component class can have a ToolboxItemFilterType of Prevent for the toolbox item to be enabled.

The following code example demonstrates how to apply the ToolboxItemFilterAttribute.

Imports System
Imports System.Collections
Imports System.ComponentModel
Imports System.ComponentModel.Design
Imports System.Diagnostics
Imports System.Drawing
Imports System.Drawing.Design
Imports System.Windows.Forms
Imports System.Windows.Forms.Design

' This example contains an IRootDesigner that implements the IToolboxUser interface.
' This example demonstrates how to enable the GetToolSupported method of an IToolboxUser
' designer in order to disable specific toolbox items, and how to respond to the 
' invocation of a ToolboxItem in the ToolPicked method of an IToolboxUser implementation.
' This example component class demonstrates the associated IRootDesigner which 
' implements the IToolboxUser interface. When designer view is invoked, Visual 
' Studio .NET attempts to display a design mode view for the class at the top 
' of a code file. This can sometimes fail when the class is one of multiple types 
' in a code file, and has a DesignerAttribute associating it with an IRootDesigner. 
' Placing a derived class at the top of the code file solves this problem. A 
' derived class is not typically needed for this reason, except that placing the 
' RootDesignedComponent class in another file is not a simple solution for a code 
' example that is packaged in one segment of code.

Public Class RootViewSampleComponent
    Inherits RootDesignedComponent
End Class

' The following attribute associates the SampleRootDesigner with this example component.
<DesignerAttribute(GetType(SampleRootDesigner), GetType(IRootDesigner))> _
Public Class RootDesignedComponent
    Inherits System.Windows.Forms.Control
End Class

' This example IRootDesigner implements the IToolboxUser interface and provides a 
' Windows Forms view technology view for its associated component using an internal 
' Control type.     
' The following ToolboxItemFilterAttribute enables the GetToolSupported method of this
' IToolboxUser designer to be queried to check for whether to enable or disable all 
' ToolboxItems which create any components whose type name begins with "System.Windows.Forms".
<ToolboxItemFilterAttribute("System.Windows.Forms", ToolboxItemFilterType.Custom)> _
<System.Security.Permissions.PermissionSetAttribute(System.Security.Permissions.SecurityAction.Demand, Name:="FullTrust")> _
Public Class SampleRootDesigner
    Inherits ParentControlDesigner
    Implements IRootDesigner, IToolboxUser

    ' Member field of custom type RootDesignerView, a control that is shown in the 
    ' design mode document window. This member is cached to reduce processing needed 
    ' to recreate the view control on each call to GetView().
    Private m_view As RootDesignerView

    ' This string array contains type names of components that should not be added to 
    ' the component managed by this designer from the Toolbox.  Any ToolboxItems whose 
    ' type name matches a type name in this array will be marked disabled according to  
    ' the signal returned by the IToolboxUser.GetToolSupported method of this designer.
    Private blockedTypeNames As String() = {"System.Windows.Forms.ListBox", "System.Windows.Forms.GroupBox"}

    ' IRootDesigner.SupportedTechnologies is a required override for an IRootDesigner.
    ' This designer provides a display using the Windows Forms view technology.
    ReadOnly Property SupportedTechnologies() As ViewTechnology() Implements IRootDesigner.SupportedTechnologies
        Get
            Return New ViewTechnology() {ViewTechnology.Default}
        End Get
    End Property

    ' This method returns an object that provides the view for this root designer. 
    Function GetView(ByVal technology As ViewTechnology) As Object Implements IRootDesigner.GetView
        ' If the design environment requests a view technology other than Windows 
        ' Forms, this method throws an Argument Exception.
        If technology <> ViewTechnology.Default Then
            Throw New ArgumentException("An unsupported view technology was requested", "Unsupported view technology.")
        End If

        ' Creates the view object if it has not yet been initialized.
        If m_view Is Nothing Then
            m_view = New RootDesignerView(Me)
        End If
        Return m_view
    End Function

    ' This method can signal whether to enable or disable the specified
    ' ToolboxItem when the component associated with this designer is selected.
    Function GetToolSupported(ByVal tool As ToolboxItem) As Boolean Implements IToolboxUser.GetToolSupported
        ' Search the blocked type names array for the type name of the tool
        ' for which support for is being tested. Return false to indicate the
        ' tool should be disabled when the associated component is selected.
        Dim i As Integer
        For i = 0 To blockedTypeNames.Length - 1
            If tool.TypeName = blockedTypeNames(i) Then
                Return False
            End If
        Next i ' Return true to indicate support for the tool, if the type name of the
        ' tool is not located in the blockedTypeNames string array.
        Return True
    End Function

    ' This method can perform behavior when the specified tool has been invoked.
    ' Invocation of a ToolboxItem typically creates a component or components, 
    ' and adds any created components to the associated component.
    Sub ToolPicked(ByVal tool As ToolboxItem) Implements IToolboxUser.ToolPicked
    End Sub

    ' This control provides a Windows Forms view technology view object that 
    ' provides a display for the SampleRootDesigner.
    <DesignerAttribute(GetType(ParentControlDesigner), GetType(IDesigner))> _
    Friend Class RootDesignerView
        Inherits Control
        ' This field stores a reference to a designer.
        Private m_designer As IDesigner

        Public Sub New(ByVal designer As IDesigner)
            ' Performs basic control initialization.
            m_designer = designer
            BackColor = Color.Blue
            Font = New Font(Font.FontFamily.Name, 24.0F)
        End Sub

        ' This method is called to draw the view for the SampleRootDesigner.
        Protected Overrides Sub OnPaint(ByVal pe As PaintEventArgs)
            MyBase.OnPaint(pe)
            ' Draws the name of the component in large letters.
            pe.Graphics.DrawString(m_designer.Component.Site.Name, Font, Brushes.Yellow, New RectangleF(ClientRectangle.X, ClientRectangle.Y, ClientRectangle.Width, ClientRectangle.Height))
        End Sub
    End Class
End Class

Windows 98, Windows Server 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.

.NET Framework

Supported in: 3.0, 2.0, 1.1, 1.0
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