XElement.SetAttributeValue Method

Sets the value of an attribute, adds an attribute, or removes an attribute.

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

public void SetAttributeValue(
	XName name,
	Object value


Type: System.Xml.Linq.XName
An XName that contains the name of the attribute to change.
Type: System.Object
The value to assign to the attribute. The attribute is removed if the value is null. Otherwise, the value is converted to its string representation and assigned to the Value property of the attribute.


The value is an instance of XObject.

This method is designed to make it easy to maintain a list of name/value pairs as a set of attributes. When maintaining the list, you need to add pairs, modify pairs, or delete pairs. If you call this method passing a name that does not exist as an attribute, this method creates an attribute for you. If you call this method passing the name of an existing attribute, this method modifies the value of the attribute to the value that you specify. If you pass null for value, this method removes the attribute.

This method will raise the Changed and the Changing events.

The value is assigned to the attribute with the specified name. If no attribute with the specified name exists, a new attribute is added. If the value is null, the attribute with the specified name, if any, is deleted.

For more information, see Maintaining Name/Value Pairs in the .NET Framework documentation.

The following example creates an element with an attribute. It then uses this method to replace the content of the attribute.

StringBuilder output = new StringBuilder();
// Create an element with no content.
XElement root = new XElement("Root");

// Add some name/value pairs.
root.SetAttributeValue("Att1", 1);
root.SetAttributeValue("Att2", 2);
root.SetAttributeValue("Att3", 3);
output.Append(root + Environment.NewLine);

// Modify one of the name/value pairs.
root.SetAttributeValue("Att2", 22);
output.Append(root + Environment.NewLine);

// Remove one of the name/value pairs.
root.SetAttributeValue("Att3", null);
output.Append(root + Environment.NewLine);

OutputTextBlock.Text = output.ToString();


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Community Additions