CODEWITHSUNDEEP
c#wpf.net-4.6.1
Ben Bancroft
Ben Bancroft

Reputation: 105

Why DataGridComboBoxColumn CellStyle won't apply padding

Some days I really regret ever going down the route of using WPF for an application...

I am trying to use DataGridComboBoxColumn and all I want to do is apply padding to the text in the cell when it is not being edited but it seems they made that an impossible task

<Window.Resources>
    <CollectionViewSource x:Key="Statuses" Source="{Binding Path=Statuses}" />        
</Window.Resources>

<DataGridComboBoxColumn Header="Status"
                        Width="100"
                        ItemsSource="{Binding Source={StaticResource Statuses}}"
                        DisplayMemberPath="Description"
                        SelectedValuePath="Index"
                        SelectedValueBinding="{Binding Path=Status}">
    <DataGridComboBoxColumn.CellStyle>
        <Style TargetType="{x:Type DataGridCell}">
            <Setter Property="Padding" Value="4,2" />
        </Style>
    </DataGridComboBoxColumn.CellStyle>
</DataGridComboBoxColumn>

I tried setting ElementStyle and overriding the Template but this just causes some weird validation error and after a quick internet search it seems this is a bad option to take.

I then resorted to using a DataGridTemplateColumn but this leaves me trying to convert my Binding Value back into the same text as the ComboBox DisplayMemberPath and my attempt at using a ValueConverter failed as it never passed a value from my CollectionViewSource "Statuses".

Now I have run out of patience and will just have to accept that I can't style these cells, unless someone out there has a quick and reliable fix for this?

Edit: I have created a GitHub Repository with an example of what I am trying to do, there is also a branch named 'value-converter' with my failed attempt at implementing IValueConverter and using DataGridTemplateColumn.

Upvotes: 2

Views: 457

Answers (2)

Brian THOMAS
Brian THOMAS

Reputation: 534

Have you tried setting Margin for the ElementStyle?

<DataGridComboBoxColumn.ElementStyle>
    <Style TargetType="{x:Type ComboBox}">
        <Setter Property="Margin" Value="5,0,5,0"/>
    </Style>
</DataGridComboBoxColumn.ElementStyle>

Upvotes: 0

mm8
mm8

Reputation: 169350

The easiest way to fix this is probably to define a custom ComboBoxColumn and set the Margin property of the element generated in the GenerateElement method:

public class CustomComboBoxColumn : System.Windows.Controls.DataGridComboBoxColumn
{
    protected override FrameworkElement GenerateElement(DataGridCell cell, object dataItem)
    {
        FrameworkElement fe = base.GenerateElement(cell, dataItem);
        if (fe is Control control)
            control.Margin = new Thickness(4, 2, 4, 2);
        return fe;
    }
}

Usage:

<local:CustomComboBoxColumn Header="Status"
                                    Width="100"
                                    ItemsSource="{Binding Source={StaticResource Statuses}}"
                                    DisplayMemberPath="Description"
                                    SelectedValuePath="Index"
                                    SelectedValueBinding="{Binding Path=Status}" />

Upvotes: 1

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