How do I dynamically generate columns in a WPF DataGrid?

Question

I am attempting to display the results of a query in a WPF datagrid. The ItemsSource type I am binding to is IEnumerable<dynamic>. As the fields returned are not determined until runtime I don't know the type of the data until the query is evaluated. Each "row" is returned as an ExpandoObject with dynamic properties representing the fields.

It was my hope that AutoGenerateColumns (like below) would be able to generate columns from an ExpandoObject like it does with a static type but it does not appear to.

<DataGrid AutoGenerateColumns="True" ItemsSource="{Binding Results}"/>

Is there anyway to do this declaratively or do I have to hook in imperatively with some C#?

EDIT

Ok this will get me the correct columns:

// ExpandoObject implements IDictionary<string,object> 
IEnumerable<IDictionary<string, object>> rows = dataGrid1.ItemsSource.OfType<IDictionary<string, object>>();
IEnumerable<string> columns = rows.SelectMany(d => d.Keys).Distinct(StringComparer.OrdinalIgnoreCase);
foreach (string s in columns)
    dataGrid1.Columns.Add(new DataGridTextColumn { Header = s });

So now just need to figure out how to bind the columns to the IDictionary values.

Answer 1

my answer from http://stackoverflow.com/questions/1753187/dynamic-column-binding-in-xaml

I've used an approach that follows the pattern of this pseudocode

columns = New DynamicTypeColumnList()
columns.Add(New DynamicTypeColumn("Name", GetType(String)))
dynamicType = DynamicTypeHelper.GetDynamicType(columns)

DynamicTypeHelper.GetDynamicType() generates a type with simple properties. See this post for the details on how to generate such a type

Then to actually use the type, do something like this

Dim rows as List(Of DynamicItem)
Dim row As DynamicItem = CType(Activator.CreateInstance(dynamicType), DynamicItem)
row("Name") = "Foo"
rows.Add(row)
dataGrid.DataContext = rows

Answer 2

Ultimately I needed to do two things:

1. Generate the columns manually from the list for properties returned by the query
2. Set up a DataBinding object

After that the built in data binding kicked in and worked fine and didn't seem to have any issue getting the property values out of the ExpandoObject.

<DataGrid AutoGenerateColumns="False" ItemsSource="{Binding Results}"/>

and

// Since there is no guarantee that all the ExpandoObject's have the 
// same set of properties, get the complete list of distinct property names
// this represents the list of columns
IEnumerable<IDictionary<string, object>> rows = dataGrid1.ItemsSource.OfType<IDictionary<string, object>>();
IEnumerable<string> columns = rows.SelectMany(d => d.Keys).Distinct(StringComparer.OrdinalIgnoreCase);
foreach (string text in columns)
{
    // now set up a column and binding for each property
    var column = new DataGridTextColumn 
    {
        Header = text,
        Binding = new Binding(text)
    };

    dataGrid1.Columns.Add(column);
}