ControlDesigner Class

Definition

public ref class ControlDesigner : System::Web::UI::Design::HtmlControlDesigner

public class ControlDesigner : System.Web.UI.Design.HtmlControlDesigner

type ControlDesigner = class
    inherit HtmlControlDesigner

Public Class ControlDesigner
Inherits HtmlControlDesigner

Inheritance

Object

ComponentDesigner

HtmlControlDesigner

ControlDesigner

Derived

System.Web.DynamicData.Design.DynamicDataManagerDesigner

System.Web.UI.Design.ContainerControlDesigner

System.Web.UI.Design.DataSourceDesigner

System.Web.UI.Design.ExtenderControlDesigner

System.Web.UI.Design.HierarchicalDataSourceDesigner

More…

Examples

The following code example demonstrates how to create a simple designer class that derives from the ControlDesigner class. This control designer supports a custom TextControl class and provides a command to change the text size of a control at design time. The control designer is associated with the control by specifying the control designer in a DesignerAttribute object declaration on the TextControl class. The key to persisting property changes from the control designer to the HTML markup is found in the ToggleTextSize method of the custom ActionList class.

To try the example, add a reference to the System.Design.dll assembly and compile the code.

using System;
using System.Web.UI;
using System.Drawing;
using System.Web.UI.Design;
using System.Web.UI.WebControls;
using System.ComponentModel;
using System.ComponentModel.Design;

namespace ASPNet.Design.Samples.CS
{
    // Simple text Web control renders a text string.
    // This control is associated with the TextSizeWebControlDesigner.
    [DesignerAttribute(typeof(TextSizeWebControlDesigner)),
    ToolboxData("<{0}:TextControl runat=\"server\"></{0}:TextControl>")]
    public class TextControl : Label
    {
        private bool _largeText = true;

        // Constructor
        public TextControl()
        {
            Text = "Test Phrase";
            SetSize();
        }

        // Determines whether the text is large or small
        [Bindable(true), Category("Appearance"), DefaultValue("true")]
        public bool LargeText
        {
            get { return _largeText; }
            set
            {
                _largeText = value;
                SetSize();
            }
        }

        // Applies the LargeText property to the control
        private void SetSize()
        {
            if (LargeText)
                this.Font.Size = FontUnit.XLarge;
            else
                this.Font.Size = FontUnit.Small;
        }
    }

    // This control designer offers DesignerActionList commands
    // that can alter the design time html of the associated control.
    public class TextSizeWebControlDesigner : ControlDesigner
    {
        private DesignerActionListCollection _actionLists = null;

        // Do not allow direct resizing of the control
        public override bool AllowResize
        {
            get { return false; }
        }

        // Return a custom ActionList collection
        public override DesignerActionListCollection ActionLists
        {
            get
            {
                if (_actionLists == null)
                {
                    _actionLists = new DesignerActionListCollection();
                    _actionLists.AddRange(base.ActionLists);

                    // Add a custom DesignerActionList
                    _actionLists.Add(new ActionList(this));
                }
                return _actionLists;
            }
        }

        public class ActionList : DesignerActionList
        {
            private TextSizeWebControlDesigner _parent;
            private DesignerActionItemCollection _items;

            // Constructor
            public ActionList(TextSizeWebControlDesigner parent)
                : base(parent.Component)
            {
                _parent = parent;
            }

            // Create the ActionItem collection and add one command
            public override DesignerActionItemCollection GetSortedActionItems()
            {
                if (_items == null)
                {
                    _items = new DesignerActionItemCollection();
                    _items.Add(new DesignerActionMethodItem(this, "ToggleLargeText", "Toggle Text Size", true));
                }
                return _items;
            }

            // ActionList command to change the text size
            private void ToggleLargeText()
            {
                // Get a reference to the parent designer's associated control
                TextControl ctl = (TextControl)_parent.Component;

                // Get a reference to the control's LargeText property
                PropertyDescriptor propDesc = TypeDescriptor.GetProperties(ctl)["LargeText"];

                // Get the current value of the property
                bool v = (bool)propDesc.GetValue(ctl);

                // Toggle the property value
                propDesc.SetValue(ctl, !v);
            }
        }
    }
}

Imports System.Web.UI
Imports System.Web.UI.Design
Imports System.Web.UI.WebControls
Imports System.ComponentModel
Imports System.ComponentModel.Design

Namespace ASPNet.Design.Samples.VB

    ' Simple text Web control renders a text string.
    ' This control is associated with the TextSizeWebControlDesigner.
    <DesignerAttribute(GetType(TextSizeWebControlDesigner)), _
        ToolboxData("<{0}:TextControl runat='server'></{0}:TextControl>")> _
    Public Class TextControl
        Inherits Label

        Private _largeText As Boolean = True

        ' Constructor
        Public Sub New()
            Text = "Test Phrase"
            SetSize()
        End Sub

        ' Determines whether the text is large or small
        <Bindable(True), Category("Appearance"), DefaultValue(True)> _
        Public Property LargeText() As Boolean
            Get
                Return _largeText
            End Get
            Set(ByVal value As Boolean)
                _largeText = value
                SetSize()
            End Set
        End Property

        ' Applies the LargeText property to the control
        Private Sub SetSize()
            If LargeText Then
                Me.Font.Size = FontUnit.XLarge
            Else
                Me.Font.Size = FontUnit.Small
            End If
        End Sub
    End Class


    ' This control designer offers DesignerActionList commands
    ' that can alter the design time html of the associated control.
    Public Class TextSizeWebControlDesigner
        Inherits ControlDesigner

        Private _actionLists As DesignerActionListCollection

        ' Do not allow direct resizing of the control
        Public Overrides ReadOnly Property AllowResize() As Boolean
            Get
                Return False
            End Get
        End Property

        ' Return a custom ActionList collection
        Public Overrides ReadOnly Property ActionLists() As System.ComponentModel.Design.DesignerActionListCollection
            Get
                If IsNothing(_actionLists) Then
                    _actionLists = New DesignerActionListCollection()
                    _actionLists.AddRange(MyBase.ActionLists)

                    ' Add a custom DesignerActionList
                    _actionLists.Add(New ActionList(Me))
                End If

                Return _actionLists
            End Get
        End Property

        ' Create a custom class of DesignerActionList
        Public Class ActionList
            Inherits DesignerActionList
            Private _parent As TextSizeWebControlDesigner
            Private _items As DesignerActionItemCollection

            ' Constructor
            Public Sub New(ByRef parent As TextSizeWebControlDesigner)
                MyBase.New(parent.Component)
                _parent = parent
            End Sub

            ' Create the ActionItem collection and add one command
            Public Overrides Function GetSortedActionItems() As DesignerActionItemCollection
                If IsNothing(_items) Then
                    _items = New DesignerActionItemCollection()
                    _items.Add(New DesignerActionMethodItem(Me, "ToggleLargeText", "Toggle Text Size", True))
                End If

                Return _items
            End Function

            ' ActionList command to change the text size
            Private Sub ToggleLargeText()
                ' Get a reference to the parent designer's associated control
                Dim ctl As TextControl = CType(_parent.Component, TextControl)

                ' Get a reference to the control's LargeText property
                Dim propDesc As PropertyDescriptor = TypeDescriptor.GetProperties(ctl)("LargeText")

                ' Get the current value of the property
                Dim v As Boolean = CType(propDesc.GetValue(ctl), Boolean)
                ' Toggle the property value
                propDesc.SetValue(ctl, (Not v))
            End Sub
        End Class
    End Class
End Namespace

<%@ Page Language="C#" %>
<%@ Register TagPrefix="aspSample" 
    Namespace="ASPNet.Design.Samples.CS" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<script runat="server">

</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
    <aspSample:TextControl ID="TextControl1" runat="server">
    </aspSample:TextControl>

    
    </div>
    </form>
</body>
</html>

<%@ Page Language="VB" %>
<%@ Register TagPrefix="aspSample" 
    Namespace="ASPNet.Design.Samples.VB" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" 
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
    <title>Untitled Page</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    
        <aspSample:TextControl ID="TextControl1" runat="server">
        </aspSample:TextControl>
    
    </div>
    </form>
</body>
</html>

Remarks

The ControlDesigner class provides a base control designer class that can be inherited from and extended to provide design-time support for a Web server control in a design host, such as Visual Studio 2005.

The object model for working with design-time rendering is improved over earlier versions, with the following new base classes to provide access to the simplified object model:

• ControlDesigner, which is not new, but has been greatly improved.

• ContainerControlDesigner.

• CompositeControlDesigner.

Automatic Formatting

You can create a variety of automatic and pre-defined formats that can simplify the process of page developers who are applying complex style changes to custom Web server controls. For example, the TableDesigner control, which derives from the ControlDesigner class, provides many automatic formats from which to choose. To implement and provide automatic formatting in your custom controls, use the following features:

• The AutoFormats property.

• The OnAutoFormatApplied method.

• The DesignerAutoFormat class.

• The DesignerAutoFormatStyle class.

Action Lists (Smart Tags)

Action lists are menus of important or widely used tasks that a page developer who uses a control can perform in a design-time user interface (UI), such as Visual Studio 2005. For example, the design-time view of your control could provide a menu of available tasks. This includes a task to format the control automatically. To learn about action lists, start with the following features:

• The ActionLists property.

• The DesignerActionList class.

• The GetSortedActionItems method.

• The DesignerActionListCollection class.

• The DesignerActionMethodItem class.

• The DesignerActionPropertyItem class.

Control Designer Regions

Regions are editable areas in the design-time view of a Web server control. This feature offers WYSIWYG-like editing of the template content, inner controls, and properties at design time. You can have the control designer create controls in regions or you can use the Toolbox to drag and drop controls into regions. Regions are managed with the following features:

• The OnClick method.

• The DesignerRegion class.

• The EditableDesignerRegion class.

• The GetEditableDesignerRegionContent method.

• The SetEditableDesignerRegionContent method.

Templates

The model for creating a UI for design-time editing of templated controls, such as the GridView control, has been greatly improved from earlier versions. You can create complex custom controls that include templates for various parts of the control, and your custom control designer can help page developers who are modifying templates with the following features:

• The TemplateGroups property.

• The InTemplateMode property.

• The TemplateGroup class.

Design-Time Rendering

The ControlDesigner class has the following methods to support design-time rendering of the Web server control. Most of these methods are the same as in earlier versions:

• The GetDesignTimeHtml method.

• The GetEmptyDesignTimeHtml method.

• The GetErrorDesignTimeHtml method.

• The UpdateDesignTimeHtml method.

• The CreatePlaceHolderDesignTimeHtml method.

Constructors

Properties

Methods

Explicit Interface Implementations

Applies to

See also

• TemplateGroup
• DesignerAutoFormat
• DesignerActionList
• DesignerRegion
• ContainerControlDesigner
• CompositeControlDesigner
• Introduction to ASP.NET Control Designers
• Design-Time Architecture
• Sample Control Designer with Action Lists and Services