If a DataSource contains multiple sources of data, you should set the DataMember property to one of the sources.

For example, if the DataSource is a DataSet contains three tables named Customers, Orders, and OrderDetails, you must specify one of the tables to bind to.

If the DataSet contains only one DataTable, you may set the DataMember property to an empty string.

You can use the SetDataBinding(object, string) method to set the DataSource and DataMember properties at the same time.