Obsolete features in. NET4

With the introduction of the new CLR and Base Class Library, Microsoft took the opportunity to do some "dirty work ". Although there are not many items actually removed, we still see the long list of discarded types and members listed by Microsoft.

Some obsolete features are obvious. For example, it is impossible to capture ExecutionEngineException again now, so that the Code has no reason to do so. Other obsolete features reflect changes in the way CLR works. The most obvious difference is the Code Access Security and Evidence objects.

XmlDataDocument class (developers can use this class to process DataSet objects in xml dom objects) has been deprecated. Although this function is rarely used in actual development, we can still implement this function through DataSet. WriteXml and the easier-to-use XDocument class. Some classes are also discarded in the Data namespace, such as OracleCommand and OracleConnection under OracleClient. Microsoft recommends that developers use third-party implementations.

On the Web side, Microsoft gave up its mobile support for ASP. NET. Instead, we recommend that developers use ASP. net mvc. Scott Hanselman gave a speech on this technology at MIX2009 entitled "Mobile Web Sites with ASP. net mvc and the Mobile Browser Definition File ". Mobile Browser Definition File is an open-source project operated by Microsoft. It is used to classify and program the functions of all mainstream Mobile devices.

Finally, some methods are marked as obsolete from the very beginning. For example, this parallel variable of GroupJoin is created for a specific purpose and should not be used. In conclusion, this prevents developers from accidentally using non-parallel variables based on IEnumerable.