How to: Work with Dictionaries Using LINQ to XML
It is often convenient to convert varieties of data structures to XML, and XML back to other data structures. This topic shows a specific implementation of this general approach by converting a Dictionary<TKey, TValue> to XML and back.
Example
The C# version of this example uses a form of functional construction in which a query projects new XElement objects, and the resulting collection is passed as an argument to the constructor of the Root XElement object.
The Visual Basic version of this example uses XML literals and a query in an embedded expression. The query projects new XElement objects, which then become the new content for the Root XElement object.
Dictionary<string, string> dict = new Dictionary<string, string>();
dict.Add("Child1", "Value1");
dict.Add("Child2", "Value2");
dict.Add("Child3", "Value3");
dict.Add("Child4", "Value4");
XElement root = new XElement("Root",
from keyValue in dict
select new XElement(keyValue.Key, keyValue.Value)
);
Console.WriteLine(root);
Dim dict As Dictionary(Of String, String) = New Dictionary(Of String, String)()
dict.Add("Child1", "Value1")
dict.Add("Child2", "Value2")
dict.Add("Child3", "Value3")
dict.Add("Child4", "Value4")
Dim root As XElement = _
<Root>
<%= From keyValue In dict _
Select New XElement(keyValue.Key, keyValue.Value) %>
</Root>
Console.WriteLine(root)
This code produces the following output:
<Root>
<Child1>Value1</Child1>
<Child2>Value2</Child2>
<Child3>Value3</Child3>
<Child4>Value4</Child4>
</Root>
The following code creates a dictionary from XML.
XElement root = new XElement("Root",
new XElement("Child1", "Value1"),
new XElement("Child2", "Value2"),
new XElement("Child3", "Value3"),
new XElement("Child4", "Value4")
);
Dictionary<string, string> dict = new Dictionary<string, string>();
foreach (XElement el in root.Elements())
dict.Add(el.Name.LocalName, el.Value);
foreach (string str in dict.Keys)
Console.WriteLine("{0}:{1}", str, dict[str]);
Dim root As XElement = _
<Root>
<Child1>Value1</Child1>
<Child2>Value2</Child2>
<Child3>Value3</Child3>
<Child4>Value4</Child4>
</Root>
Dim dict As Dictionary(Of String, String) = New Dictionary(Of String, String)
For Each el As XElement In root.Elements
dict.Add(el.Name.LocalName, el.Value)
Next
For Each str As String In dict.Keys
Console.WriteLine("{0}:{1}", str, dict(str))
Next
This code produces the following output:
Child1:Value1
Child2:Value2
Child3:Value3
Child4:Value4