WinForms: How to Ensure Custom Drawing in DataGridView Reflects Dynamic Data Changes
I need some guidance on Quick question that's been bugging me - I'm working on a WinForms application that utilizes a `DataGridView` to display a list of products..... Each product has a stock quantity that, when updated, should change the cell's background color based on whether the stock is low (red) or sufficient (green). I've implemented custom drawing in the `CellPainting` event, but I’m working with an scenario where the colors don't update dynamically when the stock values change. Here's a snippet of my current implementation: ```csharp private void dataGridView1_CellPainting(object sender, DataGridViewCellPaintingEventArgs e) { if (e.ColumnIndex == stockColumnIndex && e.RowIndex >= 0) { int stockValue = (int)dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value; if (stockValue < 10) { e.Graphics.FillRectangle(Brushes.Red, e.CellBounds); } else { e.Graphics.FillRectangle(Brushes.Green, e.CellBounds); } e.Graphics.DrawRectangle(Pens.Black, e.CellBounds); e.Handled = true; } } ``` I have noticed that while the custom colors are applied when the form initially loads, they do not reflect updates made to the underlying data. I've tried calling `dataGridView1.Refresh()` and `dataGridView1.Invalidate()` after each data update, but it doesn’t seem to trigger the `CellPainting` event as expected. Additionally, when I try to manually refresh the data grid by re-binding the data source, I lose the custom formatting entirely. The behavior I’m seeing in the debugger often is `InvalidOperationException: 'The operation is not valid due to the current state of the object.'` when attempting to access the `Cells` collection after re-binding. I’m using .NET Framework 4.8 and the DataGridView is bound to a `BindingList<Product>` for dynamic updates. What approach should I take to ensure that the cell colors update correctly as the stock data changes? Am I missing something obvious? Any ideas how to fix this? Any feedback is welcome!