When overridden in a derived class, writes out the attribute with the specified prefix, local name, namespace URI, and value.
Type Reason ArgumentException localName is null or string.Empty . InvalidOperationException The XmlWriter.WriteState is not WriteState.Element.
This method writes out the attribute with a user defined namespace prefix and associates it with the given namespace. If the prefix is "xmlns" then this method also treats this as a namespace declaration and associates the declared prefix with the namespace URI provided in the given attribute value. In this case the ns argument can be null.
WriteAttributeString does the following:
If the attribute value includes double or single quotes, they are replaced with " and ' respectively.
If writing an xml:space attribute, the writer verifies the attribute value is valid. (Valid values are preserve or default.)
If writing an xml:lang attribute, the writer does not verify that the attribute value is valid according to the W3C XML 1.0 recommendation.
For the asynchronous version of this method, see XmlWriter.WriteAttributeStringAsync(string, string, string, string).