Passing a value from Window 2 to Main window when double click WPF

Question

I have 2 Windows, Main window has a button that opens Window 2.

Windows 2 contains datagrid holding a list of values, The user double-click to select a row from the list and closes Window 2 filling some text boxes with the data of the selected row

Some example code I have:

public class User {
    public string FirstName {get; set;}
    public string LastName { get; set;}
}

private void Button_Click(object sender, KeyEventArgs e) {
    Window2 window = new(DataToRetrieve);
    window.ShowDialog();
    
    //Get data here to and print in the text boxes
    //textbox.Text = itemRetrieved.Something;

}

My method for grabbing the item from the datagrid with MouseDoubleClick event

private void dataGrid_MouseDoubleClick(object sender, MouseButtonEventArgs e) {
  if (sender != null)
  {
    DataGrid grid = sender as DataGrid;
    if (grid != null && grid.SelectedItems != null && grid.SelectedItems.Count == 1)
    {
       DataGridRow dgr = grid.ItemContainerGenerator.ContainerFromItem(grid.SelectedItem) as DataGridRow;
       DataRowView dr = (DataRowView)dgr.Item;
    }
  }
}

How should able to send over my main window the data of the list picked to my main window?

Answer 1

You could for example add a property to the second window where you store the selected data, e.g.:

public DataRowView SelectedData { get; private set; }

private void dataGrid_MouseDoubleClick(object sender, MouseButtonEventArgs e)
{
    if (sender != null)
    {
        DataGrid grid = sender as DataGrid;
        if (grid != null && grid.SelectedItems != null && grid.SelectedItems.Count == 1)
        {
            DataGridRow dgr = grid.ItemContainerGenerator.ContainerFromItem(grid.SelectedItem) as DataGridRow;
            this.SelectedData = (DataRowView)dgr.Item;
        }
    }
}

Then you just use this property in the MainWindow:

private void Button_Click(object sender, KeyEventArgs e) 
{
    Window2 window = new(DataToRetrieve);
    window2.ShowDialog();

    // Get data here...
    textbox.Text = window2.SelectedData["someColumn"].ToString();

}