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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.

When possible, use DataReaders instead of DataTables

Why this might happen:

• Although they are less efficient for simpler tasks, DataTables can do everything that DataReaders can, so someone may not realize and may just use a DataTable when a DataReader could have done everything they needed more efficiently.

Issue with this method:

• DataTables create an in-memory copy of all the data.  They are useful for manipulating data in memory or updating the database, but tends to be rather inefficient for just pulling data out of a database.
• Performance affected: Both

Solutions:

• DataReader is more efficient at pulling out data and displaying it, as it just reads one row at a time out of the database and doesn't keep anything in memory.
• DataTables still have uses beyond those provided by DataReader, so sometimes they are still needed to filter, sort or otherwise manipulate the data before populating the workbook.

Downloads

You can download the code for the best performance samples as a Visual Studio solution.

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