How to override automate creation of data grid column header?

Question

since WPF creates column headers automatically based on which class is holding data, I'd like to ask if there is a possibility to override this process?

For example, having this class

public class Report
{
    public string Value { get; set; }
    public int Title { get; set; }
}

I will receive 2 columns - | Value | Title |

As I see it now, WPF creates those columns headers by getting the name of property and "pastes" plain output of what it gets

something like this?

nameof(property);

The goal I want to achieve is to create a custom attribute for the property like

[Header("Price in €")]
public string Value { get; set}

and let WPF create column header based on that attribute, so my columns would be like this -

| Price in € | Title |

My question is how to override this?

You could set in your xaml autogeneratecolumns to false, and create manually the columns, setting the headers yourself. [check this out](https://www.wpf-tutorial.com/datagrid-control/custom-columns/) — Magnetron, Oct 16 '18 at 15:47
Yes I know, but I guess I would have to do it programmatically what I want to avoid because with every change in class, let's suppose I would add/delete property, I would have to add/delete column header manually. And also it's more convenient and easier to set column headers in attributes — Steve, Oct 16 '18 at 15:50
There is an event that is fired when the column is generated, I think it's possible to use it to do what you want, I just don't remember which event it is. I'll check. — Magnetron, Oct 16 '18 at 15:51

score 2 · Accepted Answer · answered Oct 16 '18 at 16:01

You can create a simple Behavior for that.

I will use the ComponentModel.DescriptionAttribute in this example, but you can of course use any custom attribute.

using System.ComponentModel;
using System.Windows.Interactivity;

class ExtendendHeadersBehavior : Behavior<DataGrid>
{
    protected override void OnAttached()
    {
        AssociatedObject.AutoGeneratingColumn += AssociatedObject_AutoGeneratingColumn;
    }

    protected override void OnDetaching()
    {
        AssociatedObject.AutoGeneratingColumn -= AssociatedObject_AutoGeneratingColumn;
    }

    private void AssociatedObject_AutoGeneratingColumn(object sender, DataGridAutoGeneratingColumnEventArgs e)
    {
        if (e.PropertyDescriptor is PropertyDescriptor desc)
        {
            string header = desc.Attributes.OfType<DescriptionAttribute>()
                .FirstOrDefault()?.Description;

            if (!string.IsNullOrEmpty(header))
            {
                e.Column.Header = header;
            }
        }      
    }
}

Usage:

<DataGrid>
    <i:Interaction.Behaviors>
        <b:ExtendendHeadersBehavior/>
    </i:Interaction.Behaviors>
</DataGrid>

The namespaces are:

xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
xmlns:b="clr-namespace:YourAppNamespace"

How did you add `System.Windows.Interactivity`? I couldn't find the assembly it belongs to. — Magnetron, Oct 16 '18 at 16:23
@Magnetron, refer to [this question](https://stackoverflow.com/questions/8360209/how-to-add-system-windows-interactivity-to-project). — dymanoid, Oct 16 '18 at 16:24
It's hard finding, but what I've done is just simply wait till all References load up and then type starting with System then Windows AND THEN Interactivity, Visual Studio is tricky — Steve, Oct 16 '18 at 16:48

How to override automate creation of data grid column header?

1 Answers1