DataGrid新的DataContext之后的事件

Question

in my WPF Window I have DataGrid .
DataGrid loads data from DataTable like:

gridData.DataContext = dataTable

All works fine, DataGrid is filled by data from Stored procedure by Data Table. Depends on kind of data, Columns of DataGrid has different Width and I want get this Widths AFTER DataGrid is filled by data. Which event I have to handle to do this? I tried DataContextChanged , Loaded , AutoGenratedColumns , SourceUpdated - but all of them seems to be called before DataGrid is filled by data.

Any solution?

Answer 1

You can use several approaches to catch the moment when DataGrid's ItemsSource is changed:

1. Use DependencyPropertyDescriptor:

     DependencyPropertyDescriptor itemsSourcePropertyDescriptor = DependencyPropertyDescriptor.FromProperty(ItemsControl.ItemsSourceProperty, typeof(DataGrid)); itemsSourcePropertyDescriptor.AddValueChanged(dataGrid1, OnDataGridItemsSourceChanged); private void OnDataGridItemsSourceChanged(object sender, EventArgs e) { } 

2. Create a DataGrid descendant and override the OnItemsSourceChanged method

Answer 2

There is no bulletproof way as the DataGrid doesn't raise any "columns generated" event but you should be able to call Dispatcher.Invoke with a DispatcherPriority lower than DispatcherPriority.Loaded once the DataGrid has been loaded, eg:

dataGrid.AutoGenerateColumns = true;
dataGrid.ItemsSource = new List<Item> { new Item() { Name = "some very long name..." } };
dataGrid.Loaded += (s, e) => 
{
    dataGrid.Dispatcher.Invoke(new Action(() =>
    {
        MessageBox.Show(dataGrid.Columns[0].ActualWidth.ToString());
    }), System.Windows.Threading.DispatcherPriority.Input);
};