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• Loop through a large number of cells, setting styles on each cell individually.
• Set group of cells to an area, then apply that style to the area.

  Code Block

  /* INCORRECT CODE: Style randDataStyle = wb.CreateStyle(); randDataStyle.BackgroundColor = wb.Palette.GetClosestColor(162, 221, 139); randDataStyle.HorizontalAlignment = Style.HAlign.Center; ColumnProperties columnProperties; System.Random rand = new System.Random(); for (int iRow = 1; iRow < 50; iRow++) { for (int iCol = 0; iCol < 3; iCol++) { ws.Cells[iRow, iCol].Value = rand.Next(100); ws.Cells[iRow, iCol].ApplyStyle(randDataStyle); } } */

Why this method causes issues:

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• Apply styles to large numbers of cells by setting the style to either rows/columns or to singular data marker cells.
• If more than one style is needed in a row/column, and it can't be handled by switching the style for the other (ie, setting style on a row to change part of a column), try to keep the style that takes a majority of the row/column as the one set by that row/column.

  Code Block

  // POSSIBLE CORRECT CODE: Style randDataStyle = wb.CreateStyle(); randDataStyle.BackgroundColor = wb.Palette.GetClosestColor(162, 221, 139); randDataStyle.HorizontalAlignment = Style.HAlign.Center; ColumnProperties columnProperties; // Loop through the 2-4 columns to apply formatting for (int i = 1; i < 4; i++) { columnProperties = ws.GetColumnProperties(i); columnProperties.Width = 100; columnProperties.ApplyStyle(randDataStyle); }

When Possible, Use DataReaders Instead of DataTables

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