DataGridView not rendering random cells

Question

I have a datagridview which I am populating from a datasource using dgv.DataSource = table. I then use a cell formatting event to change the color of specific cells in the datagridview depending on a value. The problem that I am facing is that when looking at the data on certain pc's some random cells will appear white with no data in. The code I am using to set the color is below however it is not just the cells which I have set custom colors which appear white:

    private void dgvRaw_CellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
    {
        if (e != null)
        {
            DataGridView dgv = (DataGridView)sender;

            if (dFlags.ContainsKey(dgv.Columns[e.ColumnIndex].Name))
            {
                e.CellStyle.ForeColor = Color.Black;
                // If pass set green else set red 
                if (e.Value != null)
                {
                    if (e.Value.ToString() == "0")
                        e.CellStyle.BackColor = System.Drawing.Color.Green;
                    else
                        e.CellStyle.BackColor = System.Drawing.Color.Red;
                }
                else
                    e.CellStyle.BackColor = System.Drawing.Color.Orange;
            }
        }
    }

I literally have no idea why this is happening or if it is due to the computers not being able to cope with rendering large grid view. Thanks!

In order to eliminate any display bug from the equation, try checking the source code : is the data in it ? If yes but it's not displayed : display bug. If not... then it's something else, and very strange — Laurent S., May 21 '13 at 16:42
It depends on the query, but probably somewhere on average of 100 columns and 1000 rows. I have the same problem with a smaller data grid view which only has 10 columns and 5-20 rows so I am skeptical that it is to do with the size of the dataset — manicmonkey21421, May 21 '13 at 16:43
How about trying to refresh the grid using `dgv.refresh()` ? — Ofiris, May 21 '13 at 16:44
@Bartdude I know the data is in it because if a cell is clicked on the data will then appear however another white cell will sometimes appear somewhere else, especially if highlighting data. — manicmonkey21421, May 21 '13 at 16:45
@Ofiris I think I have tried this in the past to no effect however I will give it a go on one of the pcs where it is an issue tomorrow when I have access. Thanks for the answer though! — manicmonkey21421, May 21 '13 at 16:48
from what you describe, it really looks like a display bug indeed, although I don't see why you would have it on smaller gridviews , a 10x20 table is no big deal, unless you're talking about very very limited client computer... — Laurent S., May 21 '13 at 16:51
@Bartdude Yes, thats what I feared. These computers are not actually that low spec and I have noticed it happen on my computer a few times but nowhere near as much. If that is the case there isnt really anything I can do unless double buffering? — manicmonkey21421, May 21 '13 at 16:55
are there line breaks in the data? Maybe the data is being displayed, it's just not visible due to clipping. — jugg1es, May 21 '13 at 17:45
@jugg1es No, it was literally just random cells. I have managed to fix the issue (I believe) by using a custom datagridview with the double buffering property set to true. I will post it as the answer as soon as I know the issue has been fixed. Thanks for all your help! — manicmonkey21421, May 22 '13 at 07:47

score 0 · Accepted Answer · answered May 23 '13 at 07:03

As it turns out the issue with the datagridview was that double buffering is not enabled by default. I used a custom datagridview class to enable double buffering and since then I have not had any issues, I suspect because there was such a large dataset it was having problems rendering the entire area and on the lower end pcs it was just giving up. I have included the class below

    /// <summary>
    /// Custom datagridview to enable double buffering
    /// </summary>
    public class MyDataGridView : DataGridView
    {
        public MyDataGridView()
        {
            DoubleBuffered = true;
        }
    }

I cannot take credit for this code as I found it on another source on Stack Overflow however it was for a different problem.

DataGridView not rendering random cells

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