A Dataset maintains an index, or many indexes, to facilitate the high performance when it is traversed for data. An example of such a situation is when you use the Find or a Select option looking to filter for DataRows on a condition.

So, when you are loading rows into the DataTable with the DataAdapter.Fill or AddRow or Merger, you should indicate to the DataTable that it should switch off this index maintenance when rows are loaded.

You can do this by using the “BeginLoadData” method of the datatable.

dataTable.BeginLoadData()dataSet.Tables[0].BeginLoadData()

However, you also need to turn it on at the end of loading the data. You can do it by using the following code:

EndLoadData method of the DataTable.dataTable.EndLoadData();dataTable.Tables[0].EndLoadData()