ViewTechnology Enum

Definition

Defines identifiers for a set of technologies that designer hosts support.

C#
public enum ViewTechnology
C#
[System.Runtime.InteropServices.ComVisible(true)]
public enum ViewTechnology
Inheritance
ViewTechnology
Attributes

Fields

Name Value Description
Passthrough 0

Represents a mode in which the view object is passed directly to the development environment.

The view object must implement any interfaces the development environment requires. The Visual Studio development environment supports view objects that are either an ActiveX control, active document, or an object that implements the IVsWindowPane interface that is available through the Visual Studio VSI (Visual Studio Integration) program. The Visual Studio development environment provides support for this view technology. Support for this view technology is not necessarily available in all development environments.

WindowsForms 1

Represents a mode in which a Windows Forms control object provides the display for the root designer. The designer host fills the development environment document window with the Windows Forms control.

Default 2

Specifies the default view technology support.

The root designer may return any type of object, but the object must be compatible with an adapter for the technology of the host. Hosting environments such as Visual Studio provide a way to plug in new view technology adapters. The default view object for the Windows Forms designer is a Control instance.

Examples

The following example demonstrates how to use ViewTechnology.Default in a designer. This example is part of a larger example provided for the GetView interface.

C#
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Diagnostics;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.Design;

namespace SampleRootDesigner
{	
    // This sample demonstrates how to provide the root designer view, or
    // design mode background view, by overriding IRootDesigner.GetView().

    // This sample component inherits from RootDesignedComponent which 
    // uses the SampleRootDesigner.
    public class RootViewSampleComponent : RootDesignedComponent
    {
        public RootViewSampleComponent()
        {
        }
    }

    // The following attribute associates the SampleRootDesigner designer 
    // with the SampleComponent component.
    [Designer(typeof(SampleRootDesigner), typeof(IRootDesigner))]
    public class RootDesignedComponent : Component
    {
        public RootDesignedComponent()
        {
        }
    }

    public class SampleRootDesigner : ComponentDesigner, IRootDesigner
    {
        // Member field of custom type RootDesignerView, a control that 
        // will be shown in the Forms designer view. This member is 
        // cached to reduce processing needed to recreate the 
        // view control on each call to GetView().
        private RootDesignerView m_view;			

        // This method returns an instance of the view for this root
        // designer. The "view" is the user interface that is presented
        // in a document window for the user to manipulate. 
        object IRootDesigner.GetView(ViewTechnology technology) 
        {
            if (technology != ViewTechnology.Default)
            {
                throw new ArgumentException("Not a supported view technology", "technology");
            }
            if (m_view == null)
            {
                   // Some type of displayable Form or control is required 
                   // for a root designer that overrides GetView(). In this 
                   // example, a Control of type RootDesignerView is used.
                   // Any class that inherits from Control will work.
                m_view = new RootDesignerView(this);
            }
            return m_view;
        }

        // IRootDesigner.SupportedTechnologies is a required override for an
        // IRootDesigner. Default is the view technology used by this designer.  
        ViewTechnology[] IRootDesigner.SupportedTechnologies 
        {
            get
            {
                return new ViewTechnology[] {ViewTechnology.Default};
            }
        }

        // RootDesignerView is a simple control that will be displayed 
        // in the designer window.
        private class RootDesignerView : Control 
        {
            private SampleRootDesigner m_designer;

            public RootDesignerView(SampleRootDesigner designer)
            {
                m_designer = designer;
                BackColor = Color.Blue;
                Font = new Font(Font.FontFamily.Name, 24.0f);
            }

            protected override void OnPaint(PaintEventArgs pe)
            {
                base.OnPaint(pe);

                // Draws the name of the component in large letters.
                pe.Graphics.DrawString(m_designer.Component.Site.Name, Font, Brushes.Yellow, ClientRectangle);
            }
        }		
    }
}

The following example demonstrates how to use the `ViewTechnology> enumeration in a designer. This example is part of a larger example provided for the LocalizationExtenderProvider class.

C#
using System;
using System.Collections;
using System.ComponentModel;
using System.ComponentModel.Design;
using System.Diagnostics;
using System.Drawing;
using System.Windows.Forms;
using System.Windows.Forms.Design;

// This example demonstrates adding localization support to a component hierarchy from a 
// custom IRootDesigner using the LocalizationExtenderProvider class.
namespace LocalizationExtenderProviderExample
{	
    // RootViewDesignerComponent is a component associated with the SampleRootDesigner
    // IRootDesigner that provides LocalizationExtenderProvider localization support.
    // This derived class is included at the top of this example to enable 
    // easy launching of designer view without having to put the class in its own file.
    public class RootViewDesignerComponent : RootDesignedComponent
    {  
        public RootViewDesignerComponent()
        {            
        }
    }

    // The following attribute associates the RootDesignedComponent with the RootDesignedComponent component.
    [Designer(typeof(SampleRootDesigner), typeof(IRootDesigner))]
    public class RootDesignedComponent : Component
    {
        public RootDesignedComponent()
        {
        }    
    }

    // Example IRootDesigner implementation demonstrates LocalizationExtenderProvider support.
    internal class SampleRootDesigner : IRootDesigner
    {
        // RootDesignerView Control provides a full region designer view for this root designer's associated component.
        private RootDesignerView m_view;			
        // Stores reference to the LocalizationExtenderProvider this designer adds, in order to remove it on Dispose.
        private LocalizationExtenderProvider extender;        
        // Internally stores the IDesigner's component reference
        private IComponent component;                
        
        // Adds a LocalizationExtenderProvider for the component this designer is initialized to support.
        public void Initialize(System.ComponentModel.IComponent component)
        {
           this.component = component;
            
            // If no extender from this designer is active...
            if( extender == null )
            {
                // Adds a LocalizationExtenderProvider that provides localization support properties to the specified component.
                extender = new LocalizationExtenderProvider(this.component.Site, this.component);
            }
        }

        // Provides a RootDesignerView object that supports ViewTechnology.WindowsForms.
        object IRootDesigner.GetView(ViewTechnology technology) 
        {
            if (technology != ViewTechnology.WindowsForms)
            {
                throw new ArgumentException("Not a supported view technology", "technology");
            }
            if (m_view == null )
            {
                // Create the view control. In this example, a Control of type RootDesignerView is used.
                // A WindowsForms ViewTechnology view provider requires a class that inherits from Control.
                m_view = new RootDesignerView(this, this.Component);
            }
            return m_view;
        }

        // This designer supports the WindowsForms view technology.
        ViewTechnology[] IRootDesigner.SupportedTechnologies 
        {
            get
            {
                return new ViewTechnology[] {ViewTechnology.WindowsForms};
            }
        }
        
        // If a LocalizationExtenderProvider has been added, removes the extender provider.
        protected void Dispose(bool disposing)
        {            
            // If an extender has been added, remove it
            if( extender != null  )  
            {
                // Disposes of the extender provider.  The extender 
                // provider removes itself from the extender provider
                // service when it is disposed.
                extender.Dispose();
                extender = null;                
            }            
        }

        // Empty IDesigner interface property and method implementations
        public System.ComponentModel.Design.DesignerVerbCollection Verbs
        {
            get
            {
                return null;
            }
        }

        public System.ComponentModel.IComponent Component
        {
            get
            {
                return this.component;
            }
        }

        public void DoDefaultAction()
        {            
        }

        public void Dispose()
        {        
        }
        
        // RootDesignerView is a simple control that will be displayed in the designer window.
        private class RootDesignerView : Control
        {
            private SampleRootDesigner m_designer;   
            private IComponent comp;
            
            public RootDesignerView(SampleRootDesigner designer, IComponent component)
            {
                m_designer = designer;                        
                this.comp = component;      
                BackColor = Color.Blue;
                Font = new Font(FontFamily.GenericMonospace, 12);
            }

            // Displays the name of the component and the name of the assembly of the component 
            // that this root designer is providing support for.
            protected override void OnPaint(PaintEventArgs pe)
            {
                base.OnPaint(pe);

                if( m_designer != null && comp != null )
                {
                    // Draws the name of the component in large letters.
                    pe.Graphics.DrawString("Root Designer View", Font, Brushes.Yellow, 8, 4);                    
                    pe.Graphics.DrawString("Design Name  : "+comp.Site.Name, new Font("Arial", 10), Brushes.Yellow, 8, 28);                    
                    pe.Graphics.DrawString("Assembly    : "+comp.GetType().AssemblyQualifiedName, new Font("Arial", 10), Brushes.Yellow, new Rectangle(new Point(8, 44), new Size(ClientRectangle.Width-8, ClientRectangle.Height-44)));                   

                    // Uses the site of the component to acquire an ISelectionService and sets the property grid focus to the component.
                    ISelectionService selectionService = (ISelectionService)comp.Site.GetService(typeof(ISelectionService));
                    if( selectionService != null )                
                        selectionService.SetSelectedComponents( new IComponent[] { m_designer.component } );             
                }
            }
        }
    }
}

Remarks

The view adapter model replaces and adds functionality to the ViewTechnology feature; however, the ViewTechnology feature is retained for both backward compatibility and future use, if you choose.

ViewTechnology defines identifiers that can indicate the mode to use for controlling the display of a designer-hosted document.

You should only use the Default value in your designer hosting environment. In previous versions of the .NET Framework, the ViewTechnology enumeration specified the type of UI model supported by a root designer. Because this model is not extensible, you should instead use a view adapter model. A view adapter is a type that adapts an object of one type to another.

For example, an HTML designer might return a DemoDOM tree as its view. The HTML designer returns a view technology of Default. A Windows Forms hosting environment would have one or more view adapter classes available. If one such class could convert the DemoDOM into a Windows Forms control, the hosting application can support this type of designer. If no adapter can handle the data type returned from the designer's GetView method, the load of the designer will fail, and the user will be presented with an error.

Visual Studio has an extensible scheme for providing view adapters, so it can adapt to any UI technology. Third-party technology providers can also offer an appropriate view adapter, and their object models are immediately consumable.

Applies to

Product Versions
.NET Core 2.0, Core 2.1, Core 2.2, Core 3.0, Core 3.1, 5, 6, 7, 8, 9
.NET Framework 1.1, 2.0, 3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
.NET Standard 2.0, 2.1