CGXStyle::SetValueType() allows you to specify the value type in a cell. Possible types are:

CGXStyle::GetValueType() returns the value type of the cell.

SetValueType() does not affect the way values are stored in CGXStyle. All values are stored as a string. SetValueType() only offers additional information about the value that is stored in the cell. For example, when you apply numeric formatting to a cell, it will only affect the cell if its value type is GX_VT_NUMERIC.

The value type information is very important when you pass style objects to the formula engine. The formula engine parses values to determine if they should be stored as strings or as numbers. It is very important for the formula engine to distinguish between numbers and strings.

The following methods pertain to number formatting:

These methods let you format number values for static cells and specify the precision of the value (the number of significant digits).

Objective Grid lets you format number values for inactive cells and specify the precision when appropriate. The formatted value is displayed only for static (inactive) cells. If you start editing a cell, the original value is displayed.

For example, if you store the value 122.2345 in a cell and then set the format as fixed with two decimals, 122.23 is displayed in the cell. When you click the cell make the cell active, the cell value changes to 122.2345. Once the cell is nactive again, the display text reverts to 122.23.

When you apply numeric formatting to a cell, it affects the cell only if the value type is GX_VT_NUMERIC.

Objective Grid supports the following formats. For certain format types, you can also specify the number of places (referred to as 'N' in Table 8).

Use CGXStyle::SetFormat() to apply number formatting to cells.

By default, when using the GX_FMT_FIXED format type only, Objective Grid displays 0.0, with any precision, as negative. This is not always desirable.

Use SetNegativeZeroFlag(BOOL bDisplayNegativeZero = TRUE) to change the default of TRUE to FALSE.

For example, if you store the value 0.00004 with a precision of 4 using SetPlaces(4), the number displayed is -0.0000 by default.

However, if you set SetNegativeZeroFlag(FALSE), the number is displayed without the negative, as 0.0000.

Here is an example, as written in a Grid application's View.cpp file in Grid's OnIntialUpdate() function:

Also note that this formatting is applied only when the number displayed is all zeros.

If we change the above example's value to 0.00005 or higher with the same precision of 4, the number displayed is 0.0001.

This functionality is also available in Objective Grid's CGXPropertySheet-derived class CGXStyleSheet as well as in Grid's resource files gxres.rc, gxresdeu.rc, gxresfra.rc and gxresnld.rc. The relevant check box is Display Negative Zero? which is checked by default on the Format property sheet page.

For an example of this usage, see the updated GridApp sample. Simply run the sample, select GRIDAP document from the New dialog window, select the Format menu option, then Cells... and then select the Format tab in the Cells dialog. The Display Negative Zero check box or one of its shipped translations, displays on the right below the Precision edit box.

By default, Objective Grid does not use regional settings when you choose to format numbers. So, it cannot understand that 1.345,13 is a number, and format it properly, even if your system's regional settings are set so that period is the thousands separator and comma is the decimal separator. To get Objective Grid to use your regional settings, add a call to CGXGridCore:: EnableLocaleNumbers() in your grid's Initialize() or OnInitialUpdate() call. After that, any cell using a CGXEditControl that has been formatted using one of the codes listed below will use the numeric locale settings. In addition, with this setting enabled, Objective Grid will recognize values typed into numeric formatted cells as being numerical values.

No matter what the locale settings, the actual numerical values stored in the grid's data object use a period as the decimal separator and do not contain any thousands separator. This convention makes the grid's serialization locale independent. Numbers serialized from a grid using Italian settings can be read into a grid using English settings without losing the numerical values.

Also, for historical reasons, Objective Grid catches system changes through handling the WM_WININICHANGE message. If your code implements a handler for the newer WM_SETTINGCHANGE message, make sure you return a FALSE in your message handler so the grid's handler will also be called.

To customize this behavior, derive your control from CGXEditControl and override one of these three virtual CGXEditControl methods.

By default in a non-formula grid, the code below will display 1234.5555 as 1,234.56 no matter what your regional settings are. But if you add a call to EnableLocaleNumbers() in your initialization code, the formatting will reflect your regional settings. For example, using Italian locale settings would display the value 1234.5555 as 1.234,56.