When i double click on WPF DataGrid row for get cell value, return NULL

Question

I get this error in my code in MouseDoubleClick event.

Error: System.NullReferenceException: 'Object reference not set to an instance of an object.'

<DataGrid x:Name="dtgTarafDovvom" Style="{StaticResource DataGridStyle1}" ItemsSource="{Binding}" MouseDoubleClick="dtgTarafAvval_MouseDoubleClick">
  <DataGrid.Columns>
    <DataGridTextColumn Binding="{Binding Path=TarafeynQarardadID}" Header="کد ">
    </DataGridTextColumn>
</DataGrid>

here is my c# code

private void dtgTarafAvval_MouseDoubleClick(object sender, ouseButtonEventArgs e) {
  TarafeynQarardadDTO t = dtgTarafAvval.SelectedItem as TarafeynQarardadDTO;
  int tarafeynID = t.TarafeynQarardadID;
}

Answer 1

You may want to check if your current selected count is not zero, before retrieving the cell content. Just a little code to help you.

 private void dtgTarafAvval_MouseDoubleClick(object sender, MouseButtonEventArgs e)
    {
        if(dtgTarafAvval.SelectedCells.Count > 0)
        {
            CellValue = GetSelectedValue(dtgTarafAvval);
            //CellValue is a variable of type string.

        }
    }

    private string GetSelectedValue(DataGrid grid)
    {
        DataGridCellInfo cellInfo = grid.SelectedCells[0];
        if (cellInfo == null) return null;

        DataGridBoundColumn column = cellInfo.Column as DataGridBoundColumn;
        if (column == null) return null;

        FrameworkElement element = new FrameworkElement() { DataContext = cellInfo.Item };
        BindingOperations.SetBinding(element, TagProperty, column.Binding);

        return element.Tag.ToString();
    }

PS: Above code works for SelectionUnit = 'FullRow'