fpDoubleSingle Control

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The fpDoubleSingle control is a formatted edit control that supports floating-point numbers and supports many numeric formats.

You can limit the range of values allowed in the control by specifying minimum and maximum values, customize how the user interacts with the control, and add buttons to the control to customize user interaction.

Displaying a Separator Character | Working with Negative Numbers | Customizing User Entry | Setting and Returning Floating-Point Values | Formatting Decimal Values | Providing Buttons | Validating Floating-Point Data

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Displaying a Separator Character
You can group digits using a separator character to assist readability. For example, it is common in the United States to represent large figures with commas separating every three digits to show multiples of one thousand, as shown in the figure. By default, the fpDoubleSingle control does not display a separator character. If you format the control to display a separator character, but do not specify the character to display, the control displays the separator character specified by the international or regional Windows settings.

Working with Negative Numbers
You can customize the format for displaying negative numbers. You can also let the user toggle the control’s value between positive and negative by pressing the hyphen key or the minus key on the numeric keypad. By default, the fpDoubleSingle control displays a negative value as a minus sign followed by the numeric value. You can specify that the control display any of the formats illustrated to the right.

Customizing User Entry
By default, user entry is restricted because the fpDoubleSingle control checks each character as the user types it or when the user pastes data into the control. If the user tries to type or paste a character that is not valid for the control, the control does not accept the character, and a UserError event occurs. You can specify that the control beeps when the user types or pastes an invalid character. You can also restrict user entry by making the control read-only or static. You can specify that the cursor stay in the rightmost position in the control as the user types characters. If you prefer, you can configure the control so it does not check each character as it is supplied, and lets the user type or paste invalid characters. The value supplied to the fpDoubleSingle control can contain only numbers and a decimal symbol (though the control can supply additional formatting characters, such as a separator character).

Setting and Returning Floating-Point Values
You can set floating-point values using the Text property. You can return floating-point values with or without formatting characters. The fpDoubleSingle control maintains the decimal precision of the control’s value until the value is edited, even if the number of decimal places displayed is restricted. Three properties and one function/method return the value of the control. They differ in whether they maintain the precision and return the formatting of the value, and whether they return the value as a string or as a number.
Text Returns value as string with formatting, does not maintain precision UnFmtText Returns value as string without formatting, maintains precision Value Returns value as string without formatting, does not maintain precision DoubleValue Returns value as number without formatting, maintains precision

Formatting Decimal Values
You can configure the control to display decimal values with formatting to assist readability and consistency. You can specify the decimal symbol, the number of digits in the decimal portion, and whether placeholding zeros are displayed. In addition, values less than 1.0 and greater than –1.0 can display a zero in the integer portion. By default, the fpDoubleSingle control determines the decimal symbol, the number of decimal digits, and whether the control displays a leading zero using the international or regional Windows settings. This figure illustrates a fpDoubleSingle control that displays a comma as the decimal symbol, three digits in the decimal portion, a placeholding zero, and a leading zero.

Providing Buttons
The fpDoubleSingle control can display buttons to let the user quickly change the value in the control without typing. You can choose which type of buttons to display and the amount by which the value of the control changes when the user clicks a button. A commonly used button style for the fpDoubleSingle control is the spin button. By default, spin buttons increment and decrement the value of the control. You can specify the amount by which the integer and decimal portions are changed. To increment or decrement the integer portion, click a button when the cursor is in the integer portion. To increment or decrement the decimal portion, click a button when the cursor is in the decimal portion.

Validating Floating-Point Data
NOTE: Be sure to read the Customizing User Entry* section above for information on validation of data while being entered by the user.* When the fpDoubleSingle control loses the focus, it checks the value of the control to see whether it is valid. Valid values are defined as numeric values, and values are limited by the settings of the MinValue and MaxValue properties. If an invalid value is received, an InvalidData event occurs after the control loses the focus. You can change the fpDoubleSingle control’s appearance to reflect that it has received invalid data. In addition, you can specify whether and how invalid data is displayed. You can specify whether the control allows the Null value. If the control allows the Null value as a valid value, the control is blank when it contains the Null value, and it displays as its background color the color specified by the NullColor property. Otherwise, the control displays its default value, zero.