By default, the grid displays values in Boolean columns as check boxes (the column's data type determined by the DataType property). If you don't want Boolean values displayed as check boxes, set the column's Format property to a string containing the values that should be displayed for True and False values, separated by a semi-colon. For example:

flex.Cols["CheckBoxes"].DataType = typeof(bool);
flex.Cols["yesNo"].DataType = typeof(bool);
flex.Cols["yesNo"].Format := "Yes;No";

In unbound mode, you can use the GetCellCheck(int, int) and SetCellCheck(int, int, CheckEnum) methods to add check boxes to any cells. The check boxes will be displayed along with any text in the cell, and you can set their position using the column's ImageAlign property.

There are two types of check boxes: Boolean and tri-state. Boolean check boxes toggle between the Checked and Unchecked states. Tri-state check boxes cycle through the settings TSChecked, TSUnchecked, and TSGrayed.

For example, the code below creates a Boolean checkbox in cell (3,3) and a tri-state checkbox in cell (4,3):

flex.SetCellCheck(3, 3, CheckEnum.Unchecked)   // Boolean;
flex.SetCellCheck(4, 3, CheckEnum.TSUnchecked) // tri-state;