The DataGridView.SelectionMode property must be set to DataGridViewSelectionMode.FullRowSelect or DataGridViewSelectionMode.RowHeaderSelect for the DataGridView.SelectedRows property to be populated with selected rows.

This property contains a read-only snapshot of the selection at the time it is referenced. If you hold onto a copy of this collection, it may differ from the actual, subsequent System.Windows.Forms.DataGridView state in which the user may have changed the selection. You should therefore not operate on a copy of the collection.

To programmatically select a row, set its DataGridViewRow.Selected property to true.

Namespace: System.Windows.Forms
Assembly: System.Windows.Forms (in System.Windows.Forms.dll)
Assembly Versions: 2.0.0.0
Since: .NET 2.0