SUMMARY
This article provides a roadmap to learn and master data
binding using ASP.NET Web Forms. To assist you with learning a Microsoft
product or technology, roadmap articles provide links to useful information,
including online documentation, Microsoft Knowledge Base articles, and white
papers.
This article contains the following sections:
- Overview
- Architecture
- QuickStart Tutorials
- How To Articles
- Walkthroughs
- Troubleshooting
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Overview
With Web Forms pages, you can display information by binding
controls to a source of data (as with most types of forms). However, data
binding in Web Forms pages is somewhat different from data binding in other
technologies, because of the nature of Web Forms pages themselves and the
architecture of Web programming. With .NET Windows Forms and Web Forms, you can
now bind to virtually any property of a control.
This topic provides
background information about data binding in Web Forms pages, how to work with
data binding in your Web applications, and where you can find more information
about data binding and data access in Web Forms pages.
Data binding
in Web Forms pages is flexible. You can bind any property of a control to data.
This flexibility makes data binding in Web Forms pages different from previous
types of date binding. In other types of data binding, you typically bind the
display property (for example, the text property of a text box) to the data
source.
In Web Forms pages, your data source can be almost any type
of information that is available to the page, whether the information comes
from a database, from an XML document, from another control or process, or even
from a calculation that you perform yourself.
With Web Forms data
binding you can assign this data to any property of any control. Therefore, you
can use data binding to perform actions such as:
- Set the text to display in a TextBox, Label, Button,
LinkButton, or other control.
- Set the target page (the HREF attribute) of a link
control.
- Bind a CheckBox control to a Boolean value to directly set
the checked state of the control.
- Set the graphic of an Image control by binding its ImageUrl
property to a database column containing the URL or name of a graphics
file.
- Set the color, font, or size of controls. This can be
useful as a way of implementing user preferences that you store in a database
or other data store.
In other words, data binding is a way to automatically set any
run-time accessible property of any control on the page.
For overview
information about data binding by using ASP.NET Web Forms, visit the following
Microsoft Web sites:
For additional information, click the article number below
to view the article in the Microsoft Knowledge Base:
307860 ASP.NET Data Binding Overview
Architecture
You can bind any single-value Web server control property to a
data value (for example, you can bind the Text property of a TextBox or the
ImageUrl property of an Image control). This includes not only display
properties, but behavior properties such as size, width, and font. You specify
single-value data binding by creating a data-binding expression. In Microsoft
Visual Studio, you can use design-time tools to create this expression
automatically. When the control performs data binding, it resolves the
expression and assigns the resulting value to the specified property. You can
data bind as many properties on a control as you want to.
For
documentation about key Web Form data binding concepts, visit the following
Microsoft Web sites:
Controls
Some Web Forms controls display values from multiple records at
one time. These controls include the Repeater, DataList, DataGrid, ListBox,
CheckBoxList, and RadioButtonList Web server controls, and the HtmlSelect
control. Other controls, such as Label, TextBox, CheckBox, and Hyperlink
controls, display single values, which in data-binding terms means values from
a single record. For more information, visit the following Microsoft Web sites:
The "Data-Binding Expressions for Web Forms Pages" Web site
describes how Web Forms control data binding is specified through the use of a
special syntax. The Web site covers the following topics:
- Advantages of using data-binding expressions
- Using the DataBinder class for binding
- Resolving data-binding expressions
Control.DataBind Method
The
Control.DataBind method binds a data source to the invoked server control and all
its child controls. Use this method to bind data from a source to a server
control. You typically use this method after you retrieve a data set through a
database query. The "Control.DataBind Method" Web page also contains an example
that demonstrates how to override the
DataBind method in a custom control.
DataBinder Class
This Web site provides support for rapid-application development
(RAD) designers to generate and parse Data Binding Expression Syntax. This
class cannot be inherited.
DataBinder Members
This Web site has a list of all the
DataBinder class members.
DataBinder.Eval Method
The
DataBinder.Eval method uses reflection to parse and evaluate a data-binding
expression against an object at run time. This method allows rapid-application
development (RAD) designers, such as Visual Studio .NET, to easily generate and
parse data-binding syntax. You can also use this method declaratively on a Web
Forms page to simplify casting from one type to another. This Web site contains
an example that shows how to use one of the overloaded versions of Eval.
Control.OnDataBinding Method
The
Control.OnDataBinding method raises the DataBinding event. This method notifies a
server control to perform any data binding logic that is associated with it.
This Web site contains an example that demonstrates how to override the
OnDataBinding method to add child controls to the parent control from a data
source.
DataBinding Class
This Web site contains information about a single data-binding
expression in an ASP.NET server control. This single data-binding expression
allows RAD designers, such as Visual Studio .NET, to create data-binding
expressions at design time. This class cannot be inherited.
DataBindingCollection Class
The
DataBindingCollection class provides a collection of DataBinding objects for an ASP.NET
server control. This class cannot be inherited. This Web site contains an
example that demonstrates how to use the DataBindingCollection constructor.
DataBindingCollection Members
The "DataBindingCollection Members" Web site has a list of all
members of the
DataBindingCollection class.
Control.DataBinding Event
The
Control.DataBinding event occurs when the server control binds to a data source. The
event handler receives an argument of the EventArgs type that contains data
that is related to this event. This event notifies the server control to
perform any data binding logic that has been written for it.
IDataBindingsAccessor Interface
With the IDataBindingsAccessor interface, the collection of
data-binding expressions on a control can be accessed at design time.
IDataBindingsAccessor Members
This Web site has a list of all the members of the
IDataBindingsAccessor interface.
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QuickStart Tutorials
For QuickStart tutorials, visit the following Microsoft Web
sites:
For more information about data binding server controls, visit
the following Microsoft GotDotNet Web site:
For more information about templated data-bound controls, visit
the following Microsoft Web site:
For more information about server controls, visit the following
Microsoft Web site:
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How To Articles
How To articles in the Microsoft Knowledge Base contain
step-by-step instructions about how to do specific tasks.
For additional information about data binding with ASP.NET
Web Forms, click the article numbers below to view the articles in the
Microsoft Knowledge Base:
308485 HOW TO: Create a Master/Detail Page with Web Form Controls
308485 HOW TO: Create a Master/Detail Page with Web Form Controls
306227 HOW TO: Use a CheckBox Web Control in a DataGrid
314334 HOW TO: Add Static Items to a DropDownList Control Using VB .NET
317429 HOW TO: Use the ItemDataBound Event in VB.Net Web Forms
317719 HOW TO: Export Data in DataGrid on an ASP. NET WebForm to Excel
313154 HOW TO: Create Summary Row for DataGrid in ASP.NET Using VB .NET
317794 HOW TO: Dynamically Create Controls in ASP.NET w/Visual C# .NET
Walkthroughs
Walkthroughs are mini-tutorials that walk you through some
typical application development scenarios using Web Forms data binding. For
walkthrough documents, visit the following Microsoft Web sites:
The "Using a DataGrid Web Control" walkthrough assists you with
developing a templated data-bound control. It is easy to bind a property of a
control to a single data item (or expression) by using ASP.NET data-binding
syntax. This section addresses the more complex scenario of developing a
control that has templated properties bound to a data source that is a
collection type (System.Collections.ICollection or
System.Collections.IEnumerable). Templates enable a page developer to customize
the presentation of data that is bound to the control. The Repeater and
DataList controls are examples of templated data-bound controls.
For
additional information about how to develop templated data-bound controls,
visit the following Microsoft Web site:
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Troubleshooting
The Microsoft newsgroups and the Microsoft Knowledge are both
valuable resources for troubleshooting.
In the Microsoft newsgroups,
your peers can answer problems and questions. To view the Microsoft newsgroups,
visit the following Microsoft Web site:
To search for articles about specific issues in the Microsoft
Knowledge Base (KB), visit the following Microsoft Web site:
For additional information to help you with troubleshooting,
visit the following Microsoft Web sites:
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