ASP.NET.in.a.Nutshell.Second.Edition [Electronic resources] نسخه متنی

Chapter 37. The System.Web.UI.Design Namespace

The System.Web.UI.Design
namespace contains types used for providing design-time support for
the Web Forms user interface. These types
fall into four basic categories: type converters, UI type editors,
designers, and other helper classes (such as classes that provide
ASP.NET data binding support). Type converters allow control
properties to be converted to and from base data types, which allows
them to be displayed and edited in the Properties Window. Type
converters also extend runtime support, but they are only used
implicitly and never instantiated directly. Type converter classes
derive from System.ComponentModel.TypeConverter
and end with the word "Converter"
by convention. Unlike type converters, UI type editors are used
exclusively in the design environment. They provide the custom user
interface that is used to select special property values from the
Properties window (like a control's color). UI type
editors derive from
System.Drawing.Design.UITypeEditor and end with
the word "Editor."

Designers help provide the design-time representation of a control.
They derive from
System.ComponentModel.Design.ComponentDesigner and
end with the word "Designer." The
System.Web.UI.Design namespace contains the base
designers used for ASP.NET controls. ASP.NET controls use different
designers than Windows Form controls because they are rendered by
using HTML rather than Windows-specific GDI+ functions. For custom
designers that extend specific controls, refer to the
System.Web.UI.Design.WebControls namespace.

Generally, the types in the System.Web.UI.Design
namespace are never used directly in the runtime logic of an
application. However, they are useful for ASP.NET control designers.
For example, if you are creating a custom Web Forms control from
scratch, you may want to derive from
ControlDesigner to create a custom designer.
However, you may find it more convenient to extend an existing web
controlin which case, you would continue using the default
designers, type converters, and UI type editors, or derive custom
versions from the corresponding control-specific class in the
System.Web.UI.Design.WebControls namespace, if it
exists.

Figure 37-1 shows the fundamental types in this
namespace, and Figure 37-2 shows the remaining
types.

Figure 37-1. Fundamental types from the System.Web.UI.Design namespace

Figure 37-2. More types from the System.Web.UI.Design namespace