WriteStartAttribute Method (String, String, String)

XmlWriter.WriteStartAttribute Method (String, String, String)


When overridden in a derived class, writes the start of an attribute with the specified prefix, local name, and namespace URI.

Namespace:   System.Xml
Assembly:  System.Xml (in System.Xml.dll)

public abstract void WriteStartAttribute(
	string prefix,
	string localName,
	string ns


Type: System.String

The namespace prefix of the attribute.

Type: System.String

The local name of the attribute.

Type: System.String

The namespace URI for the attribute.

Exception Condition

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.”

This method enables you to write a value using multiple Write methods.

For the asynchronous version of this method, see WriteStartAttributeAsync.

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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