Data Source Controls Overview
ASP.NET includes data source controls that allow you to work with different types of data sources such as a database, an XML file, or a middle-tier business object. Data source controls connect to and retrieve data from a data source and make it available for other controls to bind to, without requiring code. They can also support modifying data.
This topic provides information about the different types of data source controls in ASP.NET. The data source control model is extensible, so you can also create your own data source controls that interact with different data sources or that provide additional functionality for an existing data source.
The .NET Framework includes data source controls to support different data-binding scenarios. The following table describes the built-in data source controls. More detail about each type of data source control is provided later in this topic.
Data source control
Enables you to use Language-Integrated Query (LINQ) in an ASP.NET Web page through declarative markup in order to retrieve and modify data from a data object. Supports automatic generation of select, update, insert, and delete commands. The control also supports sorting, filtering, and paging.
Enables you to bind to data that is based on the Entity Data Model (EDM). Supports automatic generation of update, insert, delete, and select commands. The control also supports sorting, filtering and paging.
Enables you to work with a business object or other class and create Web applications that rely on middle-tier objects to manage data. Supports advanced sorting and paging scenarios unavailable with the other data source controls.
Enables you to work with Microsoft SQL Server, OLE DB, ODBC, or Oracle databases. When used with SQL Server, supports advanced caching capabilities. The control also supports sorting, filtering, and paging when data is returned as a DataSet object.
Enables you to work with a Microsoft Access database. Supports sorting, filtering, and paging when data is returned as a DataSet object.
Enables you to work with an XML file, especially for hierarchical ASP.NET server controls such as the TreeView or Menu control. Supports filtering capabilities using XPath expressions and enables you to apply an XSLT transformation to the data. The XmlDataSource allows you to update data by saving the entire XML document with changes.
Used with ASP.NET site navigation. For more information, see ASP.NET Site Navigation Overview.
The LinqDataSource control enables you to use LINQ in an ASP.NET page to retrieve data from a database table or an in-memory data collection. You can use declarative markup to write all the conditions that are required in order retrieve, filter, order, and group the data. When you retrieve data from a SQL database table, you can also configure a LinqDataSource control to handle update, insert, and delete operations. You can do this writing SQL commands to perform these tasks. By using the LinqDataSource control, you can reduce the amount of code that is required for data operations, compared to performing the same operations in other data source controls.
For more information, see LinqDataSource Web Server Control Overview.
The SqlDataSource control can return results as a DataReader or a DataSet object. It supports sorting, filtering, and caching when the results are returned as a DataSet. When you are working with Microsoft SQL Server, the control has the added benefit that cache results can be invalidated when the database changes, using a SqlCacheDependency object.
For more information, see SqlDataSource Web Server Control Overview.
The EntityDataSource control supports data binding scenarios based on the Entity Data Model (EDM). This data specification represents data as sets of entities and relationships. The Entity Framework uses the EDM in object-relational mapping and in other scenarios such as ADO.NET Data Services. The EntityDataSource control supports Entity-SQL (eSQL) as the query language, and it supports the query specification that is exposed by the ObjectQuery<(Of <(T>)>) class.
For more information, see EntityDataSource Web Server Control Overview.
The ObjectDataSource control works with a business object or other class in Web applications that rely on middle-tier business objects to manage data. The control is designed to interact with an object that implements one or more methods to retrieve or modify data. When data-bound controls interact with the ObjectDataSource control to retrieve or modify data, the ObjectDataSource control passes values from the bound control to the source object as parameters in method calls.
The source object's data-retrieval methods must return a DataSet, DataTable, or DataView object, or an object that implements the IEnumerable interface. If the data is returned as a DataSet, DataTable, or DataView object, the ObjectDataSource control can cache and filter the data. You can also implement advanced paging scenarios if the source object accepts page size and record index information from the ObjectDataSource control.
For more information, see ObjectDataSource Web Server Control Overview.
The XmlDataSource control reads and writes XML data so that you can work with it using controls such as the TreeView and Menu controls. The XmlDataSource control can read either an XML file or string of XML. If the control is working with an XML file, it can write modified XML back to the source file. If a schema is available that describes the data, the XmlDataSource control can use the schema to expose data using typed members.
You can apply an XSLT transformation to the XML data, which allows you to restructure the raw data from the XML file into a format better suited to the control you want to bind to the XML data.
You can also apply XPath expressions to the XML data, which allows you to filter the XML data to return only certain nodes in the XML tree, to look for nodes that have specific values in them, and so on. Using an XPath expression disables the ability to insert new data.
For more information, see XmlDataSource Web Server Control Overview.
The AccessDataSource control is a specialized version of the SqlDataSource control, designed to work specifically with Microsoft Access .mdb files. As with the SqlDataSource control, you use SQL statements to define how the control fetches and retrieves data.
For more information, see AccessDataSource Web Server Control Overview.
The SiteMapDataSource control works with ASP.NET site maps and provides site navigation data. It is most commonly used with the Menu control. The SiteMapDataSource control is also useful when you want to customize site navigation using site map data with Web server controls that are not specifically designed for navigation, such as the TreeView or DropDownList controls.
For more information, see SiteMapDataSource Web Server Control Overview.