The number control above is initialized with this code. The italic properties are optional.

MessageValidatorTip="true" 
    OnFocusCssClass="MaskedEditFocus" 
    OnInvalidCssClass="MaskedEditError"
    MaskType="Number" 
    InputDirection="RightToLeft" 
    AcceptNegative="Left" 
    DisplayMoney="Left"
    ErrorTooltipEnabled="True"/>

• MaskType - Type of validation to perform:
  None - No validation
  Number - Number validation
  Date - Date validation
  Time - Time validation
  DateTime - Date and time validation
• Mask Characters and Delimiters
  9 - Only a numeric character
  L - Only a letter
  $ - Only a letter or a space
  C - Only a custom character (case sensitive)
  A - Only a letter or a custom character
  N - Only a numeric or custom character
  ? - Any character
  
  / - Date separator
  : - Time separator
  . - Decimal separator
  , - Thousand separator
  \ - Escape character
  { - Initial delimiter for repetition of masks
  } - Final delimiter for repetition of masks
  
  Examples:
  9999999 - Seven numeric characters
  99\/99 - Four numeric characters separated in the middle by a "/"
•  
• AcceptAMPM - True to display an AM/PM symbol
• AcceptNegative - True if the negative sign (-) is allowed
  None - Do not show the negative sign
  Left - Show the negative sign on the left of the mask
  Right - Show the negative sign on the right of the mask
• AutoComplete - True to automatically fill in empty mask characters not specified by the user
  MaskType=Number - Empty mask characters will be filled with zeros
  MaskType=Time - Empty mask characters will be filled with the current time
  MaskType=Date - Empty mask characters will be filled with the current date
  MaskType=DateTime - Empty mask characters will be filled with the current date/time
• AutoCompleteValue - Default character to use when AutoComplete is enabled
• Century - Default century used when a date mask only has two digits for the year
• ClearMaskOnLostFocus - True to remove the mask when the TextBox loses focus
• ClearTextOnInvalid - True to clear the TextBox when invalid text is entered
• ClipboardEnabled- True to allow copy/paste with the clipboard
• ClipboardText - Prompt text to use when a clipboard paste is performed
• DisplayMoney - Specifies how the currency symbol is displayed
  None - Do not show the currency symbol
  Left - Show the currency symbol on the left of the mask
  Right - Show the currency symbol on the right of the mask
• ErrorTooltipCssClass - CSS class for the tooltip message
• ErrorTooltipEnabled - True to show a tooltip message when the mouse hovers over an invalid TextBox
• Filtered - Valid characters for mask type "C" (case-sensitive)
• InputDirection - Text input direction
  LeftToRight - Left to Right
  RightToLeft - Right to left
• MessageValidatorTip - Message displayed when editing in TextBox
• PromptChararacter - Prompt character for unspecified mask characters
• UserDateFormat - Custom date format
• UserTimeFormat - Custom time format
•  
• OnFocusCssClass - CSS class used when the TextBox receives focus
• OnFocusCssNegative - CSS class used when the TextBox gets focus with a negative value
• OnBlurCssNegative - CSS class used when the TextBox loses focus with a negative value
• OnInvalidCssClass - CSS class used when the text is not valid.
•  
• CultureName - Name of culture to use (overrides the default page culture)
• CultureAMPMPlaceholder - Culture override
• CultureCurrencySymbolPlaceholder - Culture override
• CultureDateFormat - Culture override
• CultureDatePlaceholder - Culture override
• CultureDecimalPlaceholder - Culture override
• CultureThousandsPlaceholder - Culture override
• CultureTimePlaceholder - Culture override

ControlToValidate="TextBox2" 
    IsValidEmpty="False" 
    MaximumValue="12000" 
    EmptyValueMessage="Number is required"
    InvalidValueMessage="Number is invalid"
    MaximumValueMessage="Number > 12000"
    MinimumValueMessage="Number < -100"
    MinimumValue="-100" 
    EmptyValueBlurredText="*" 
    InvalidValueBlurredMessage="*" 
    MaximumValueBlurredMessage="*" 
    MinimumValueBlurredText="*"
    Display="Dynamic" 
    TooltipMessage="Input a number: -100 up to 12.000"/>