Class DoubleTextBox

Extends the System.Windows.Forms.TextBox class to handle double input and validation.

Inheritance
System.Object
TextBoxExt
NumberTextBoxBase
NumericTextBox
DoubleTextBox
GridDoubleTextBox
Implements
System.ComponentModel.ISupportInitialize
System.Runtime.Serialization.ISerializable
Inherited Members
Namespace: Syncfusion.Windows.Forms.Tools
Assembly: Syncfusion.Shared.Base.dll
Syntax
public class DoubleTextBox : NumericTextBox, IThemeProvider, IVisualStyle, ISupportInitialize, ISerializable
Remarks

The DoubleTextBox is derived from textbox and provides all the functionality of a textbox and adds additional functionality of its own.

Collecting double input in a consistent format requires validation code that needs to be built into the application when using the Windows Forms text box control. The DoubleTextBox includes all this logic into its methods and properties and makes it easy for the developer and the end user to collect and enter double data.

The DoubleTextBox is also closely tied to the globalization settings of the operating system for number related properties. Please refer to the System.Globalization.NumberFormatInfo class for a detailed explanation of globalization and number related attributes.

The DoubleTextBox has full support for the Windows Forms designer and you can just drag-and-drop and set properties on the control just as you would with the Windows Forms text box.

The DoubleTextBox also raises a ValidationError event when in appropriate data is entered into the control.

All clipboard functions such as copy, paste and cut are also supported with special accommodations for number related issues.

Constructors

DoubleTextBox()

Overloaded. Creates an object of type DoubleTextBox.

Declaration
public DoubleTextBox()
Remarks

The DoubleTextBox object will be initialized with the default values for the display and data properties. You need to set any specific values.

Properties

AccessibilityEnabled

Gets or sets a value indicating whether the control should enable its Accessibility support.

Declaration
public bool AccessibilityEnabled { get; set; }
Property Value
Type
System.Boolean

DoubleValue

Gets or sets the double value of the control. This will be formatted and displayed.

Declaration
public double DoubleValue { get; set; }
Property Value
Type
System.Double

HideTrailingZeros

Gets or sets a value indicating whether trailing zeros should be hidden in the displayed number.

Declaration
public bool HideTrailingZeros { get; set; }
Property Value
Type
System.Boolean

MaxValue

Gets or sets the maximum value that can be set through the DoubleTextBox.

Declaration
public double MaxValue { get; set; }
Property Value
Type
System.Double

MinValue

Gets or sets the minimum value that can be set through the DoubleTextBox.

Declaration
public double MinValue { get; set; }
Property Value
Type
System.Double

Text

Overrides the Text property of System.Windows.Forms.TextBox.

Declaration
public override string Text { get; set; }
Property Value
Type
System.String
Remarks

This property is overriden in order to normalize the data that is set to the Text property and format it as needed. The method InsertString is used to format the data.

ThemeStyle

Gets or sets the DoubleTextBoxVisualStyle value used to customize the appearance of the DoubleTextBox.

Declaration
public DoubleTextBoxVisualStyle ThemeStyle { get; set; }
Property Value
Type
DoubleTextBoxVisualStyle
Remarks

This ThemeStyle settings will be applied only when the VisualStyleBased theme has been applied to the control.

UseNullString

Indicates whether the NULLString property will be used.

Declaration
[Obsolete("This property will not be used in future.Insead Use AllowNull")]
public bool UseNullString { get; set; }
Property Value
Type
System.Boolean

Methods

ApplyFormatting(String)

Formats the given text according to the current setting.

Declaration
protected override string ApplyFormatting(string rawValue)
Parameters
Type Name Description
System.String rawValue
Returns
Type
System.String
Overrides

CheckForMinMax(String, Boolean)

Checks whether the current text value is within the defined minimum and maximum range.

Declaration
protected override bool CheckForMinMax(string currentTextValue, bool ignoreLength)
Parameters
Type Name Description
System.String currentTextValue

The text value to validate.
System.Boolean ignoreLength

Indicates whether to ignore length constraints.
Returns
Type
System.Boolean
Overrides

CheckIfNegative(String)

Checks whether the specified raw value represents a negative number.

Declaration
protected override bool CheckIfNegative(string rawValue)
Parameters
Type Name Description
System.String rawValue

The raw string value to check.
Returns
Type
System.Boolean
Overrides

CheckIsZero()

Checks whether the current value is zero and not null.

Declaration
protected override bool CheckIsZero()
Returns
Type
System.Boolean
Overrides

CheckNullStringIsInRange(String)

Checks whether the null string value is within the valid range.

Declaration
protected override bool CheckNullStringIsInRange(string nullString)
Parameters
Type Name Description
System.String nullString

The string to validate.
Returns
Type
System.Boolean
Overrides

CreateAccessibilityInstance()

Creates a custom accessibility instance for the control if accessibility is enabled.

Declaration
protected override AccessibleObject CreateAccessibilityInstance()
Returns
Type
System.Windows.Forms.AccessibleObject
Overrides

Dispose(Boolean)

Releases the unmanaged resources used by the DoubleTextBox and optionally releases the managed resources.

Declaration
protected override void Dispose(bool disposing)
Parameters
Type Name Description
System.Boolean disposing

true to release both managed and unmanaged resources; false to release only unmanage resources.
Overrides

FormatChanged(String, NumberFormatInfo)

Declaration
protected override void FormatChanged(string currentText, NumberFormatInfo previousFormat)
Parameters
Type Name Description
System.String currentText
System.Globalization.NumberFormatInfo previousFormat
Overrides

GetControlName(String)

Helps to override the ThemeName property settings

Declaration
public override string GetControlName(string controlName)
Parameters
Type Name Description
System.String controlName

ThemeName
Returns
Type
System.String
Overrides

GetNumberPartLength(Double)

Gets the length of the number part from the specified double value.

Declaration
protected int GetNumberPartLength(double numberValue)
Parameters
Type Name Description
System.Double numberValue

The number value.
Returns
Type
System.Int32

GetNumberValue(String, Int32)

Extracts and returns the numeric value from the formatted text starting at the specified position.

Declaration
protected override string GetNumberValue(string formattedText, int startPosition)
Parameters
Type Name Description
System.String formattedText

The formatted text containing the number.
System.Int32 startPosition

The position to start extraction.
Returns
Type
System.String
Overrides

GetValue()

Gets the current value of the control.

Declaration
protected override object GetValue()
Returns
Type Description
System.Object

The current value as an object.
Overrides

HandleBackspaceKey()

Handles the Backspace key press event. If the current value is zero and null is allowed, sets the control to its null state.

Declaration
protected override bool HandleBackspaceKey()
Returns
Type
System.Boolean
Overrides

HandleDecimalKey()

Handles the Decimal key press event. Moves the cursor to the decimal separator or enables decimal mode if the value is null.

Declaration
protected override bool HandleDecimalKey()
Returns
Type
System.Boolean
Overrides

HandleDeleteKey()

Handles the Delete key press event. If the current value is zero and null is allowed, sets the control to its null state.

Declaration
protected override bool HandleDeleteKey()
Returns
Type
System.Boolean
Overrides

HandleSubtractKey()

Handles the Subtract key press event. If DeleteSelectionOnNegative is enabled, clears the selection at the decimal separator.

Declaration
protected override NumberModifyState HandleSubtractKey()
Returns
Type
NumberModifyState
Overrides

InitializeNumberTextBox()

Overrides InitializeNumberTextBox().

Declaration
protected override void InitializeNumberTextBox()
Overrides

IsAssignable(Object)

Determines whether the specified value is assignable to a System.Double.

Declaration
protected override bool IsAssignable(object val)
Parameters
Type Name Description
System.Object val

The value to check.
Returns
Type
System.Boolean
Overrides

IsValidNumberValue(String)

Determines whether the specified string represents a valid number.

Declaration
protected override bool IsValidNumberValue(string doubleString)
Parameters
Type Name Description
System.String doubleString

The string to validate.
Returns
Type
System.Boolean
Overrides

OnDoubleValueChanged(EventArgs)

Raises the DoubleValueChanged event.

Declaration
protected virtual void OnDoubleValueChanged(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

A System.EventArgs that contains the event data.

OnEnabledChanged(EventArgs)

Raises the System.Windows.Forms.Control.EnabledChanged event.

Declaration
protected override void OnEnabledChanged(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

An System.EventArgs that contains the event data.
Overrides

OnEnter(EventArgs)

Overrides the System.Windows.Forms.Control.OnEnter(System.EventArgs) method.

Declaration
protected override void OnEnter(EventArgs args)
Parameters
Type Name Description
System.EventArgs args

The event data.
Overrides
Remarks

Saves the current DoubleValue so that it can be compared during validation. The DoubleValueChanged and TextChanged event will only be raised if the value is different during validation.

OnGotFocus(EventArgs)

Helps to override the OnGotFocus events

Declaration
protected override void OnGotFocus(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

An System.EventArgs that contains the event data.
Overrides

OnKeyDown(KeyEventArgs)

Raises the System.Windows.Forms.Control.KeyDown event.

Declaration
protected override void OnKeyDown(KeyEventArgs e)
Parameters
Type Name Description
System.Windows.Forms.KeyEventArgs e

A System.Windows.Forms.KeyEventArgs that contains the event data.

OnLostFocus(EventArgs)

Handles the lost focus event and updates the text box formatting.

Declaration
protected override void OnLostFocus(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

An System.EventArgs that contains the event data.
Overrides

OnTextChanged(EventArgs)

Overrides OnTextChanged.

Declaration
protected override void OnTextChanged(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

The event data.
Overrides

OnThemeNameChanged(String)

Helps to apply the ThemeName settings in control

Declaration
public override void OnThemeNameChanged(string themeName)
Parameters
Type Name Description
System.String themeName

ThemeName
Overrides

OnValidated(EventArgs)

Handles the validated event and triggers control-specific validation logic.

Declaration
protected override void OnValidated(EventArgs e)
Parameters
Type Name Description
System.EventArgs e

An System.EventArgs that contains the event data.

OnValidating(CancelEventArgs)

Handles the validating event to ensure the value is within the allowed range. Applies corrective actions based on the OnValidationFailed setting.

Declaration
protected override void OnValidating(CancelEventArgs e)
Parameters
Type Name Description
System.ComponentModel.CancelEventArgs e

A System.ComponentModel.CancelEventArgs that contains the event data.
Overrides

PrepareInsertString(String, Int32, Int32, String, Boolean)

Prepares the control for inserting a string, handling formatting and validation.

Declaration
protected override NumberModifyState PrepareInsertString(string currentText, int startPosition, int selectionLength, string textToBeInserted, bool pasteOperation)
Parameters
Type Name Description
System.String currentText

The current text in the control.
System.Int32 startPosition

The position at which the new text will be inserted.
System.Int32 selectionLength

The length of the selected text to be replaced.
System.String textToBeInserted

The text to be inserted.
System.Boolean pasteOperation

Indicates whether the operation is a paste action.
Returns
Type
NumberModifyState
Overrides

ResetText()

Restores the CurrencyNumberDigits to the MaximumLength.

Declaration
protected void ResetText()

SetDoubleValue(Double)

Sets the double value of the control, applying rounding and formatting.

Declaration
protected void SetDoubleValue(double newValue)
Parameters
Type Name Description
System.Double newValue

The new double value to set.

SetNullNumberValue()

Sets the control's value to represent a null number.

Declaration
protected override void SetNullNumberValue()
Overrides

SetTextProperty(String)

Sets the text property of the control, parsing and validating the input.

Declaration
protected override void SetTextProperty(string newText)
Parameters
Type Name Description
System.String newText

The new text to assign.
Overrides

SetValue(Object)

Sets the control's value using the specified object.

Declaration
protected override void SetValue(object val)
Parameters
Type Name Description
System.Object val

The value to assign.
Overrides

ShouldSerializeText()

Indicates whether to serialize the Text property if it is null or quals NullString

Declaration
protected bool ShouldSerializeText()
Returns
Type
System.Boolean

ToggleNegative(String)

Toggles the sign of the numeric value represented by the input text. If the result is zero, updates the zero-negative state.

Declaration
protected override string ToggleNegative(string currentText)
Parameters
Type Name Description
System.String currentText

The current numeric text.
Returns
Type
System.String
Overrides

Events

DoubleValueChanged

Occurs when the DoubleValue property is changed.

Declaration
public event EventHandler DoubleValueChanged
Event Type
Type
System.EventHandler

Implements

System.ComponentModel.ISupportInitialize
System.Runtime.Serialization.ISerializable