Changing the format of a ComboBox item

Question

Is it possible to format a ComboBox item in C#? For example, how would I make an item bold, change the color of its text, etc.?

Answer 1

Just to add to the answer supplied by Dan, don't forget that if you have bound the list to a Datasource, rather than just having a ComboBox with plain strings, you won't be able to redraw the entry by using combo.Items[e.Index].ToString().

If for example, you've bound the ComboBox to a DataTable, and try to use the code in Dan's answer, you'll just end up with a ComboBox containing System.Data.DataRowView, as each item in the list isn't a string, it's a DataRowView.

The code in this case would be something like the following:

 private void ComboBox1_DrawItem(object sender, DrawItemEventArgs e)
            {
                if (e.Index == -1)
                    return;
                ComboBox combo = ((ComboBox)sender);

                using (SolidBrush brush = new SolidBrush(e.ForeColor))
                {
                    Font font = e.Font;
                    DataRowView item = (DataRowView)combo.Items[e.Index];

                    if (/*Condition Specifying That Text Must Be Bold*/) {
                        font = new System.Drawing.Font(font, FontStyle.Bold);
                    }
                    else {
                        font = new System.Drawing.Font(font, FontStyle.Regular);
                    }                    

                    e.DrawBackground();
                    e.Graphics.DrawString(item.Row.Field<String>("DisplayMember"), font, brush, e.Bounds);
                    e.DrawFocusRectangle();
                }

            }

Where "DisplayMember" is name of the field to be displayed in the list (set in the ComboBox1.DisplayMember property).

Answer 2

As old as this post is, I found it useful as a starting point to search from but ended up having better results using the method shown here by @Paul.

Here is the code I used to conditionally make items in a combo box appear bold, I find that the answer marked correct for this question has strange behaviour - when you hover over an item is goes slightly bolder and stays that way as if it is being redrawn over. This code results in a more natural look:

private void ComboBox1_DrawItem(object sender, DrawItemEventArgs e)
        {
            if (e.Index == -1)
                return;
            ComboBox combo = ((ComboBox)sender);
            using (SolidBrush brush = new SolidBrush(e.ForeColor))
            {
                Font font = e.Font;
                if (/*Condition Specifying That Text Must Be Bold*/)
                    font = new System.Drawing.Font(font, FontStyle.Bold);
                e.DrawBackground();
                e.Graphics.DrawString(combo.Items[e.Index].ToString(), font, brush, e.Bounds);
                e.DrawFocusRectangle();
            }

        }