WPF DataGrid: How to get binding expression of a cell?

Question

I need to get access to the binding expression of the DataGrid cell in a DataGridTextColumn. For example:

        <DataGridTextColumn Header="Name" Binding="{Binding Name}"/>

I managed to get the TextBlock associated with the cell:

        var cell = dataGrid.GetCellCtrl<TextBlock>(dataGrid.CurrentCell);

And cell seems to be correct. I can call

        cell.SetValue(TextBlock.TextProperty, value);

To update the cell text. It seems to be working on the grid (number updated). However, as I realize after a while, the source doesn't get updated. It didn't help even if I turn UpdateSourceTrigger to PropertyChange. Then, I thought I need to get the binding expression and call UpdateSource explicitly.

        var bindingExpr = cell.GetBindingExpression(TextBlock.TextProperty);

but bindingExpr is always null. Why?

EDIT: The original problem I had was that I can get to the binding TextBlock for the cell, and set the TextBlock.TextProperty. However, the source doesn't get updated. This is something I'm trying to resolve this problem.

Answer 1

The TextBox in the DataGridTextColumn will not have a binding expression the column itself has the binding.

DataGridTextColumn is derived from DataGridBoundColumn which uses a BindingBase property not TextBlock.TextProperty, However the Binding property is not a DependancyProperty so you will have to access using normal public properties.

So you will have to do a bit of casting as the Binding property in DataGridTextColumn is type BindingBase.

Something like this should work (untested)

var binding = (yourGrid.Columns[0] as DataGridBoundColumn).Binding as Binding;