Question

Due the nature of our software, we have to create our datagrid columns dynamically in code behind and add it then to the datagrid like this:

DataGridBoundColumn dataGridBoundColumn = new DataGridTextColumn
                                                          {
                                                              CellStyle = ...,                                                                            
                                                              Header = header,
                                                              Binding = binding
                                                          };
reportDataGrid.Columns.Add(dataGridBoundColumn);

Now we need a tooltip on the columnheader:

ToolTipService.SetToolTip(dataGridBoundColumn, "ENTER VALUE");

Well that works fine too. However I need to bind the tooltip’s value to a property on the ViewModel. I know how to do this in the xaml, but no idea how to do that in code.

Any help would be appreciated,

UPDATE:

Thanks to Steve’s answer I was able to fix this slightly differently:

Binding bindingBoundToTooltipProperty = new Binding()
                                   {
                                       Source = reportDataGrid.DataContext, 
                                       Path = new PropertyPath("ToolTipSorting")
                                   };


BindingOperations.SetBinding(dataGridBoundColumn, ToolTipService.ToolTipProperty, bindingBoundToTooltipProperty);

if the DataGridColumnHeaderStyle was customized, make sure to add these lines to the template as well:

<Trigger Property="IsMouseOver" Value="True">
    <Setter Property="ToolTip" Value="{Binding Column.(ToolTipService.ToolTip), RelativeSource={RelativeSource Self}}"/>
</Trigger>

Answer 1

You should be able to set up a binding as below:

BindingOperations.SetBinding(dataGridBoundColumn,
    ToolTipService.ToolTipProperty,
    new Binding("Path.To.My.Property"));

Note: the DataContext of this will be the value of the Header property on the column

You want to bind to a property on the view model; assuming that your view model is the DataContext for the DataGrid you would want to change the binding to something like:

new Binding("DataContext.ToolTipSorting")
{
    RelativeSource = new RelativeSource(RelativeSourceMode.FindAncestor)
    {
        AncestorType = typeof(DataGrid)
    }
}

This attempts to locate the first parent object of type DataGrid and grab the value of its DataContext.ToolTipSorting property.