The Formula Bar is a visual control (SpreadsheetFormulaBarControl) that accompanies the SpreadsheetControl. The formula bar is usually located above the worksheet area. It allows endusers to view, enter and edit data values and formulas contained in worksheet cells as well as a cell's inplace editor. The formula bar is bound to the SpreadsheetControl via the SpreadsheetFormulaBarControl.SpreadsheetControl property. To add a formula bar to your spreadsheet application, you can draganddrop the corresponding item from the DX.17.2: Spreadsheet toolbox tab or select Create FormulaBar in the SpreadsheetControl's smart tag menu (see the Getting Started example).
By default, the formula bar contains three buttons, each of which has a default action, as described in the table below. When an enduser clicks a particular button, a corresponding event is fired.
Handle these events to override the default behavior or perform additional actions when buttons are clicked, if needed. To perform the action associated with a particular button in code, use the SpreadsheetFormulaBarControl.ExecuteResourceNavigatorAction method.
A formula is a string expression that starts with an equal sign ("="). It can contain constants, operators, cell references, calls to functions, and names. An enduser can specify a cell formula in the cell's inplace editor or the formula bar, and use the following tools to enter different formula elements.

Cell References
The SpreadsheetControl allows endusers to insert cell references in formulas by selecting the desired cell ranges directly in the worksheet when editing a formula in a cell's inplace editor or formula bar. The cell ranges referenced in a formula are highlighted in different colors when an enduser edits the formula.

Defined Names
To insert a defined name into a formula, an enduser can type the name or select it from the Use in Formula list on the Formulas Ribbon tab in the Defined Names group.

Functions
The SpreadsheetControl supports a variety of functions to be used in formulas. An enduser can insert a function in a formula in one of the following ways.

Type the function name and enter its arguments in parentheses.

Select the desired function from the Function Library group on the Formulas Ribbon tab. Frequently used functions such as Sum, Average, Count Numbers, Max and Min are also listed under the AutoSum button on the Home tab in the Editing group.

Insert a function using the Insert Function dialog and specify the function parameters using the Function Arguments dialog.
An enduser can specify whether cells should show formulas or calculated values. The Show Formulas button on the Formulas tab switches this behavior.
The Calculation group on the Formulas tab contains buttons allowing an enduser to specify how formulas should be recalculated.
There are two available modes of formula calculation (the Calculation Options submenu).

Automatic  All dependent formulas are recalculated each time a cell value, formula, or name is changed. This is the default mode.

Manual  Formulas are recalculated only when an enduser explicitly requests it.
When the Manual recalculation mode is activated, an enduser can manually recalculate formulas throughout the entire workbook (Calculate Now) or in the active worksheet only (Calculate Sheet).