When overridden in a derived class, writes the XML declaration with the version "1.0".
Assembly: System.Xml (in System.Xml.dll)
This is not the first write method called after the constructor.
The encoding level of the document is determined by how the writer is implemented. For example, if an Encoding object is specified in the XmlTextWriter constructor, this determines the value of the encoding attribute. This method does not create a standalone attribute.
When WriteStartDocument is called the writer validates that what you are writing is a well-formed XML document. For example, it checks that the XML declaration is the first node, that one and only one root-level element exists, and so on. If this method is not called, the writer assumes an XML fragment is being written and applies no root level rules.
If WriteStartDocument has been called and then the WriteProcessingInstruction method is used to create another XML declaration, an exception will be thrown.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.