XmlWriter.WriteStartAttribute Method (String, String)
Writes the start of an attribute with the specified local name and namespace URI.
Assembly: System.Xml (in System.Xml.dll)
There is a character in the buffer that is a valid XML character but is not valid for the output encoding. For example, if the output encoding is ASCII, you should only use characters from the range of 0 to 127 for element and attribute names. The invalid character might be in the argument of this method or in an argument of previous methods that were writing to the buffer. Such characters are escaped by character entity references when possible (for example, in text nodes or attribute values). However, the character entity reference is not allowed in element and attribute names, comments, processing instructions, or CDATA sections.
An XmlWriter method was called before a previous asynchronous operation finished. In this case, InvalidOperationException is thrown with the message “An asynchronous operation is already in progress.”
.NET FrameworkSupported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.