XNode.PreviousNode Property (System.Xml.Linq)

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.NET Framework Class Library

XNode.PreviousNode Property

Gets the previous sibling node of this node.

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

Syntax

Visual Basic

Public ReadOnly Property PreviousNode As XNode
	Get

public XNode PreviousNode { get; }

Visual C++

public:
property XNode^ PreviousNode {
	XNode^ get ();
}

member PreviousNode : XNode

Property Value

Type: System.Xml.Linq.XNode
The XNode that contains the previous sibling node.

Remarks

If this XNode does not have a parent, or if there is no previous node, this property returns null.

The XContainer stores its child nodes as a singly-linked list of XNode objects. This means that the PreviousNode property must traverse the list of direct child nodes under the parent container. Therefore, using this property might affect your performance.

Examples

The following example uses this property to loop through nodes.

XElement xmlTree = new XElement("Root",
    new XElement("Child1", 1),
    new XText("Some Text"),
    new XElement("Child2",
        2,
        new XElement("GrandChild", "GrandChild Content")
    ),
    new XComment("a comment"),
    new XElement("Child3")
);
XNode node = xmlTree.Element("Child2");
do {
    StringBuilder sb = new StringBuilder();
    sb.Append(String.Format("NodeType: {0}", node.NodeType.ToString().PadRight(10)));
    switch (node.NodeType)
    {
        case XmlNodeType.Text:
            sb.Append((node as XText).Value);
            break;
        case XmlNodeType.Element:
            sb.Append((node as XElement).Name);
            break;
        case XmlNodeType.Comment:
            sb.Append((node as XComment).Value);
            break;
    }
    Console.WriteLine(sb.ToString());
}
while ((node = node.PreviousNode) != null);

Visual Basic

Dim xmlTree As XElement = _
    <Root>
        <Child1>1</Child1>Some Text<Child2>2
            <GrandChild>GrandChild Content</GrandChild>
        </Child2>
        <!--a comment-->
        <Child3>3</Child3>
    </Root>

Dim node As XNode = xmlTree.Element("Child2")
Do
    Dim sb As StringBuilder = New StringBuilder()
    sb.Append(String.Format("NodeType: {0}", node.NodeType.ToString().PadRight(10)))
    Select Case node.NodeType
        Case XmlNodeType.Text
            sb.Append(DirectCast(node, XText).Value)
        Case XmlNodeType.Element
            sb.Append(DirectCast(node, XElement).Name)
        Case XmlNodeType.Comment
            sb.Append(DirectCast(node, XComment).Value)
    End Select
    Console.WriteLine(sb.ToString())

    node = node.PreviousNode
Loop While (Not (node Is Nothing))

This example produces the following output:

NodeType: Element   Child2
NodeType: Text      Some Text
NodeType: Element   Child1

Version Information

.NET Framework

Supported in: 4, 3.5

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, 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.

Reference

XNode Class

System.Xml.Linq Namespace

Other Resources

LINQ to XML