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If the MultiSelect property is set to true, you can add DataGridView elements to or remove them from the selection by changing the Selected property of the element. Otherwise, setting the Selected property to true for one element automatically removes other elements from the selection.

Note that changing the value of the CurrentCell property does not alter the current selection.

You can retrieve a collection of the currently selected cells, rows, or columns through the SelectedCells, SelectedRows, and SelectedColumns properties of the DataGridView control. Accessing these properties is inefficient when every cell in the control is selected. To avoid a performance penalty in this case, use the AreAllCellsSelected method first. Additionally, accessing these collections to determine the number of selected cells, rows, or columns can be inefficient. Instead, you should use the GetCellCount, GetRowCount, or GetColumnCount method, passing in the Selected value.