CODEWITHSUNDEEP
c#wpfxamlbindingdatagrid
DerSöllinger
DerSöllinger

Reputation: 57

How to access property of DataGrid ItemsSource object in DataGridRow.CellStyle?


First of all, let me show you my classes:

public class Model
{
    public Model Parent {get; set;}
    public ObservableCollection<Model> Childs {get; set;}
    public ObservableCollection<Partner> Partners {get; set;}
    public bool IsTopElement => Parent == null;
}

public class Partner
{
    public bool IsActive {get; set;}
    public string PartnerRole {get; set;}
    public bool IsCustomer => PartnerRole == "Customer"
}

As you can see, Modelis a hierarchy as it can have a parent and a list of childs. I have a UserControl whose DataContext is set to an instance of Model. In this UserControl I have a DataGrid whose ItemsSource is bound to Partners. In this DataGrid I have a DataGridCheckBoxColumn that is bound to IsActive property of Partner object and several DataGridTextColumns. What I want to achieve is that if the current Model object is NOT the top element (has no parent), all IsActive-Checkbox cells that belong to a Partner entry whose IsCustomer == True shall be disabled.
I tried the following XAML code:

<UserControl DataContext="{Binding Model}">
    <DataGrid ItemsSource="{Binding Partners}" 
              AutoGenerateColumns="False"
              CanUserResizeRows="False"
              CanUserAddRows="False"
              CanUserDeleteRows="False"
              RowDetailsVisibilityMode="VisibleWhenSelected">
        <DataGrid.Columns>
            <DataGridCheckBoxColumn Binding="{Binding IsActive}">
                <DataGridCheckBoxColumn.CellStyle>
                    <Style TargetType="{x:Type DataGridCell}">
                        <Style.Triggers>
                            <MultiDataTrigger>
                                <MultiDataTrigger.Conditions>
                                    <Condition Binding="{Binding Model.IsTopElement}" Value="False"/>
                                    <Condition Binding="{Binding ???}"/> <!-- I'd have expected Binding="{Binding IsCustomer}" Value="True" to work, but it doesn't-->
                                </MultiDataTrigger.Conditions>
                                <Setter Property="IsEnabled" Value="False"/>
                            </MultiDataTrigger>
                        </Style.Triggers>
                    </Style>
                </DataGridCheckBoxColumn.CellStyle>
            </DataGridCheckBoxColumn>
        </DataGrid.Columns>             
    </DataGrid>
</UserControl>

The problem I'm facing now is that I don't have access to the property IsCustomer of the Partner object in the DataGrid in the second Condition of the MultiDataTrigger. So how can I access this property there? Also, I didn't expect to have access to IsTopElement property of Model in the first Condition because the ItemsSource of the DataGrid is bound to Partners but apparently I have, which is rather confusing to me.
Any help would be much appreciated. Please let me know if you need further information.

Upvotes: 1

Views: 373

Answers (1)

mm8
mm8

Reputation: 169350

The DataContext of the DataGridCell is a Partner object. You could use a {RelativeSource} to bind to the parent UserControl's DataContext. Try this:

<Style TargetType="{x:Type DataGridCell}">
    <Style.Triggers>
        <MultiDataTrigger>
            <MultiDataTrigger.Conditions>
                <Condition Binding="{Binding DataContext.IsTopElement, RelativeSource={RelativeSource AncestorType=UserControl}}" Value="False"/>
                <Condition Binding="{Binding IsCustomer}" Value="True"/>
            </MultiDataTrigger.Conditions>
            <Setter Property="IsEnabled" Value="False"/>
        </MultiDataTrigger>
    </Style.Triggers>
</Style>

Upvotes: 1

Related Questions