Paste Functionality for WPF DataGrid with DataGridTemplateColumns

Question

Hi. I recently started using the WPF Datagrid with DataGridTemplateColumns containing the WPF AutoCompleteBox, but I'm finding trouble in implementing Clipboard.Paste functionality for these DataGridTemplateColumns.

I've managed to get Clipboard.Paste working with built-in DataGridColumns via Vishal's guide here, but it doesn't work with DataGridTemplateColumns.

Delving into the OnPastingCellClipboardContent method in the DataGridColumn class, it appears that fe.GetBindingExpression(CellValueProperty) is returning null rather than the required BindingExpression.

Can anyone point me to the right direction?

public virtual void OnPastingCellClipboardContent(object item, object cellContent)
    {
        BindingBase binding = ClipboardContentBinding;
        if (binding != null)
        {
            // Raise the event to give a chance for external listeners to modify the cell content
            // before it gets stored into the cell
            if (PastingCellClipboardContent != null)
            {
                DataGridCellClipboardEventArgs args = new DataGridCellClipboardEventArgs(item, this, cellContent);
                PastingCellClipboardContent(this, args);
                cellContent = args.Content;
            }

            // Event handlers can cancel Paste of a cell by setting its content to null
            if (cellContent != null)
            {
                FrameworkElement fe = new FrameworkElement();
                fe.DataContext = item;
                fe.SetBinding(CellValueProperty, binding);
                fe.SetValue(CellValueProperty, cellContent);

                BindingExpression be = fe.GetBindingExpression(CellValueProperty);

        be.UpdateSource();

    }

}

Thanks!

Answer 1

This is because for DataGridTemplateColumns there isnt a binding. The binding is taken care of in your datatemplate. The cell datatemplate just gets the item (the item in the row) and binds to it. there is no way for the column to know what is in the cell.

I have worked around this by creating my own columns. I derive from DataGridTextColumn (if i am doing one that has text input) and override the GenerateElement and GenerateEditingElement.

This way i still have the binding property that can be used for pasting.

Answer 2

See this link for information on creating a custom column.

http://stackoverflow.com/questions/3611213/how-to-set-values-into-custom-datagridbound-column-in-wpf/3621341#3621341

Answer 3

Use ClipboardContentBinding as shown:

<DataGridTemplateColumn 
    Header="First Name" 
    SortMemberPath="FirstName" 
    ClipboardContentBinding="{Binding FirstName}" 
    >
    <DatGridTemplateColumn.CellTemplate>
        <DataTemplate>
            <TextBlock Text="{Binding FirstName}" />
        </DataTemplate>
    </DatGridTemplateColumn.CellTemplate>
    <DataGridTemplateColumn.CellEditingTemplate>
        ...
    </DataGridTemplateColumn>
</DataGridTemplateColumn>

Taken from here.