How to disable cell and apply the changes in a datagrid WPF

Question

Good morning,

 

 I am working on an application which uses a datagrid. The datagrid contains 5 columns and the content of each cells  depends of an ObservableCollection.

The  3rd column contains a combo box : when you edit a cell of the column, a combo box appears and you can select a value between four.

 

What I wanted to do is when I select the 2nd value of the combo box whis is called "Item2", the cell at the 4th column at the same row is no longer enable.

Actually I did the thing below :

 private void ComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
      string textComboBoxItem = e.AddedItems[0].ToString();
      var selectedRow = this.dataGrid.GetSelectedRow();

  
      if (textComboBoxItem!= "Item2")
      {
            this.dataGrid.GetCell(selectedRow, 4).Content = "";
            this.dataGrid.GetCell(selectedRow, 4).IsEnabled = false;
      }
}

 

It works but when I "quit" the cell with combo box, the change made by the action "isEnabled=false" is not applied. How can I male the change active ?

 

Note : The functions  GetSelectedRow(), GetCell are made for movin inside the datagrid.

 

Thanks in advance for any advice.