Image disappearing in datagridview

Question

0.00/5 (No votes)

See more:

I managed to add an image on the Header of a dataGridView.
But in runtime:
1. if I move my mouse cursor over the image header and I dont scroll down, the image is visible.
2. if I scroll down and then I move my mouse cursor over the image header, the image is NOT visible.
3. if I scroll back up to the top, and then I move my mouse cursor over the image header, the image is visible again.

How can I make the image visible all the time?
Thank you.

What I have tried:

I tried 2 separate events, and in both, I get the same issue, with image disappearance.

C#

private void dataGridView1_CellPainting_1(object sender, DataGridViewCellPaintingEventArgs e)
{
    if (e.ColumnIndex == dataGridView1.Columns.Count - 1 && e.RowIndex == -1)
    {
        Rectangle cellRectangle = dataGridView1.GetCellDisplayRectangle(6, 0, true);
        e.PaintBackground(e.ClipBounds, true);
        e.Graphics.DrawImage(new Bitmap(@"instock.png"), cellRectangle.Location.X + 5, 1, 18, 18);
        e.Handled = true;
    }
}

private void dataGridView1_Paint(object sender, PaintEventArgs e)
{
    Rectangle cellRectangle = dataGridView1.GetCellDisplayRectangle(6, 0, true);
    e.Graphics.DrawImage(new Bitmap(@"instock.png"), cellRectangle.Location.X + 5, 1, 18, 18);
}

Posted 31-Oct-21 22:55pm

_Q12_

Updated 1-Nov-21 0:07am

v2

Add a Solution

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2021-10-31T23:35:00

The (mian) problem is that you are trying to use the wrong row index to get the image size:

C#

Rectangle cellRectangle = dataGridView1.GetCellDisplayRectangle(6, 0, true);

When you scroll, row zero is no longer displayed, so it doesn't strictly have any dimensions.

If you use the header row index (-1) then it appears to work for me:

C#

private Image header = Image.FromFile(@"D:\Test Data\butHelp16x16.gif");
private void myDataGridView_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
    {
    if (e.RowIndex < 0)
        {
        Rectangle cellRectangle = myDataGridView.GetCellDisplayRectangle(0, -1, true);
        e.PaintBackground(e.ClipBounds, true);
        e.Graphics.DrawImage(header, cellRectangle.Location.X + 5, 1, 18, 18);
        e.Handled = true;
        }
    }

However, horizontal scrolling is still a problem, because the header cell dimensions change as it scrolls, and the image gets "chopped up".
To get round that, you need to invalidate the header cell every time you scroll:

C#

private void myDataGridView_Scroll(object sender, ScrollEventArgs e)
    {
    myDataGridView.InvalidateCell(myDataGridView.Columns[0].HeaderCell);
    }

[edit]
BTW: Don't create Bitmap items willy-nilly - they are a scarce resource, and you need to Dispose of them properly when you are finished. Creating them anew each time you get a Cell Paint event is going to crash your app with an "out of memory" exception pretty quickly!
[/edit]