If I drop a GridControl on a form, and place this code in form_load, then cell 2,2 is editable and all other cells are not.
private void gridControl1_Click(object sender, System.EventArgs e)
{
this.gridControl1.BaseStylesMap["Standard"].StyleInfo.ReadOnly = true;
this.gridControl1[2,2].ReadOnly = false;
}
Are you trying to do this for a GridDataBoundGrid? In a GridDataBoundGrid, you cannot directly set any cell specific properties except the CellValue (or Text). So you will have to handle the Model.QueryCellInfo event, and set the readonly property there for specific cells.
//hook the event
this.gridDataBoundGrid1.Model.QueryCellInfo += new GridQueryCellInfoEventHandler(grid_QueryCellInfo);
//the handler
private void grid_QueryCellInfo(object sender, GridQueryCellInfoEventArgs e)
{
if(e.ColIndex == 2 && e.RowIndex == 2)
e.Style.ReadOnly = false;
}