By default, users can resize the width of the row headers. You can disable this ability to set a fixed width, or you can use a content-based automatic sizing mode, which also disables user resizing.
The System.Windows.Forms.DataGridView control can adjust the width of its row headers to fit all their contents, only the contents of the first header, or only the contents of currently displayed headers. Calculating the new width using a subset of headers is useful to avoid a performance penalty when working with many rows of data.
This enumeration is used by the System.Windows.Forms.DataGridView control DataGridView.RowHeadersWidthSizeMode property and erload:System.Windows.Forms.DataGridView.AutoResizeRowHeadersWidth method.
For more information about sizing modes, see Sizing Options in the Windows Forms DataGridView Control.
The row header width adjusts to fit the contents of all the row header cells.
The row header width adjusts to fit the contents of all the row headers in the currently displayed rows.
The row header width adjusts to fit the contents of the first row header.
Users cannot adjust the column header width with the mouse.
Users can adjust the column header width with the mouse.