.net – Why is DataAnnotations ignored when using a DataGrid with AutoGenerateColumns=”True”

bindingdata-annotationsnetwpfwpfdatagrid

I'm using the WPF DataGrid to bind to a collection of a custom class. Using AutoGenerateColumns="True" in the grid XAML, the grid is created and populated just fine, but the headings are the property names, as one would expect.

I tried specifying 

<Display(Name:="My Name")>

from the System.ComponentModel.DataAnnotations namespace and that has no effect. I also tried

<DisplayName("My Name")>

from the System.ComponentModel name space but still the headings are not affected.

Is there no way to specify column headings with the AutoGenerateColumns option?

Best Answer

Using @Marc's suggestion was the beginning of the solution, but taken on it's own, the AutoGenerated columns still have the property names as headings.

To get the DisplayName, you need to add a routine (in the code behind) to handle the GridAutoGeneratingColumn event:

Private Sub OnGeneratingColumn(sender As Object, e As System.Windows.Controls.DataGridAutoGeneratingColumnEventArgs) Handles Grid.AutoGeneratingColumn
    Dim pd As System.ComponentModel.PropertyDescriptor = e.PropertyDescriptor
    e.Column.Header = pd.DisplayName
End Sub

An additional and better solution is to use the ComponentModel.DataAnnotations namespace and specify ShortName:

Public Class modelQ016
    <Display(shortname:="DB Name")>
    Public Property DBNAME As String
    ...

OnGeneratingColumn becomes:

        Dim pd As System.ComponentModel.PropertyDescriptor = e.PropertyDescriptor
        Dim DisplayAttrib As System.ComponentModel.DataAnnotations.DisplayAttribute =
            pd.Attributes(GetType(ComponentModel.DataAnnotations.DisplayAttribute))
        If Not DisplayAttrib Is Nothing Then
            e.Column.Header = DisplayAttrib.ShortName
        End If

Note that the order of attributes in the attribute array changes, so you must use the GetType(...) instead of a numeric parameter... Such fun!

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