Preview:
List<string> toRemove = dt.Columns.Cast<DataColumn>().Where(c => c.ColumnName.StartsWith("ExtraColumn")).Select(c => c.ColumnName).ToList();
foreach (var col in toRemove) dt.Columns.Remove(col);
downloadDownload PNG downloadDownload JPEG downloadDownload SVG

Tip: You can change the style, width & colours of the snippet with the inspect tool before clicking Download!

Click to optimize width for Twitter