TCustomFloatSpinEdit class

In unit Spin

The base class for a spin edit control using a floating point value.

Declaration

pascal

TCustomFloatSpinEdit = class(TCustomEdit)

Inheritance

Descends from it: TCustomSpinEdit TFloatSpinEdit

Description

TCustomFloatSpinEdit is a TCustomEdit descendant which implements the base class for the float-based spin edit control. It provides an edit control where the Float value can be entered directly, and up / down buttons which can be used to increment or decrement the value for the control.

Use the Value property to assign a floating point value to the control as a Double type. Value is a 64-bit real type in the range 5.0E-324 .. 1.7E308 (inclusive), and allows up to 15-16 digits of precision (15 digits for a negative value).

At run-time, setting Value to a number outside of the range for the real type causes Value to be updated. When neither MinValue nor MaxValue have been assigned, either -Inf or +Inf is displayed as the value for the control. If either MinValue or MaxValue has been given an explicit non-default value, the Value property is updated with corresponding range limit.

In LCL version 3.0, the floating point property editor will not allow an invalid value to be stored in the Value property at design-time. An error is raised (and handled) with the message 'Property value out of range', and the Value property is not updated.

LCL versions prior to 3.0 allowed the values +Inf, -Inf, and NaN to be assigned as the property value. These values are no longer supported in LCL version 3.0 and later.

Use the MinValue and MaxValue properties to define the lower and upper limits for the Value in the control. Like Value, they are implemented as a Double type with the same range limits. An invalid value causes the property to be set to the corresponding range limit for the real type.

Use the DecimalPlaces property to specify the number of decimal digits displayed for a value not represented using the radix/precision/exponent format for the IEE 754 value.

Use the Increment property to set the value added to or subtracted from the control Value when the up or down buttons are clicked.

Modified in LCL version 3.0 to implement range checking with floating point property editor support.

Properties

`DecimalPlaces`	public	Number of the decimal places displayed in the spin edit control.
`EditorEnabled`	public	Indicates whether the value for the control can be entered directly into its edit box.
`Increment`	public	Amount applied to the control value when the up or down arrow button is pushed.
`MinValue`	public	Minimum value allowed in the spin edit control.
`MaxValue`	public	Maximum value allowed in the spin edit control.
`Value`	public	The floating point value for the spin edit control.
`ValueEmpty`	public	Indicates that a value has not been assigned for the control.

Methods

`WSRegisterClass`	protected	Registers this component class with the current WidgetSet.
`Change`	protected	Updates Modified prior to sending control messages and signalling OnChange handler(s).
`EditingDone`	protected	Performs actions when editing has been completed for the control.
`RealGetText`	protected	Gets the value for the text in the control.
`RealSetText`	protected	Updates Modified and the TextHint display when storing the new Text value.
`TextChanged`	protected	Updates the control state when the value in Text has been changed.
`SetDecimals`	protected	Sets the value for the DecimalPlaces property.
`SetValue`	protected	Sets the value for the Value property.
`SetMaxValue`	protected	Sets the value for the MaxValue property.
`SetMinValue`	protected	Sets the value for the MinValue property.
`SetValueEmpty`	protected	Sets the value for the ValueEmpty property.
`SetIncrement`	protected	Sets the value for the Increment property.
`InitializeWnd`	protected	Creates or re-creates the handle for the windowed control.
`FinalizeWnd`	protected	Frees the handle for the windowed control.
`Loaded`	protected	Performs actions when LCL component streaming is completed.
`KeyPress`	protected	Handles key press events for the control.
`GetControlClassDefaultSize`	protected	Gets the default size for new instances of the class.
`Create`	public	Constructor for the class instance.
`GetLimitedValue`	public	Limits the specified value to the minimum and maximum values for the control.
`ValueToStr`	public	Converts the specified value to a String type using the spin edit settings.
`StrToValue`	public	Converts the specified string to a float value according to spin edit settings.