WPF与Datagrid的绑定属性

Question

I have bounded a ObservableCollection to a ItemSource to a DataGrid, however, I want to retrieve (via a setter) individual properties via the ViewModel.

Ok sounds confusing so will explain.

in my ObservableCollection, I have a property called "Active" so I want this element to be set when a user clicks on or off on a the checkbox in the DataGrid.

so the XAML

<DataGridTemplateColumn.CellTemplate>
    <DataTemplate>
        <CheckBox IsChecked="{Binding Active, Mode=TwoWay}" HorizontalAlignment="Center"></CheckBox>
    </DataTemplate>
</DataGridTemplateColumn.CellTemplate>

And I want this to trigger this code in the ViewModel when the box is unchecked or checked

private bool m_Active = false;

public bool Active
{
    get { return m_Active; }
    set
    {
        m_Active = value;

        OnPropertyChanged("Active");
    }
}

but even with two way mode on, it doesn't. Any reasons why?

Note: On the SelectedItem property of the DataGrid I can get the SelectedRow , so basically I want the selected Individual property!

Thanks

Answer 1

It sounds like you are confusing where the datagrid is looking for the 'Active' property. Since the datagrid is bound to an Observable Collection, the objects inside the observable collection need to have the 'Active' property on them, not the view model used for the view. If, however, you actually want to bind all the rows of a datagrid to a single property on the view model, you'll need to look up the ancestor tree to find the control's data context and then bind to the 'Active' property:

<CheckBox IsChecked="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type UserControl}}, Path=DataContext.Active, Mode=TwoWay}" HorizontalAlignment="Center"></CheckBox>

But, I imagine, you are looking to bind to the 'Active' property of the object in the observable collection. Check your output window when you are running your application and you should see a binding error if that property doesn't exist on the object.

Answer 2

Try using a CellEditingTemplate

<DataGridTemplateColumn.CellEditingTemplate>
                <DataTemplate>
                    <CheckBox IsChecked="{Binding Active, Mode=TwoWay}" HorizontalAlignment="Center"></CheckBox>
                </DataTemplate>
            </DataGridTemplateColumn.CellEditingTemplate>

Hope that helps

Answer 3

您是否尝试过设置UpdateSourceTrigger？

<CheckBox IsChecked="{Binding Active, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Center"></CheckBox>