You can easily add a mask for currency values using the Mask property. By default the C1MaskedTextBox control starts with its Mask not set but you can customize this at design time, in XAML, and in code. For more details about mask characters, see Mask Elements.
Run your project and observe:
The mask will appear in the control:
Enter a number; notice that the mask is filled:
Normally, you can use the backspace key to delete characters from the right end of a masked textbox, regardless of their type. However, when you try to delete characters from a specific spot within the textbox, whether by backspace or delete, the masked textbox may stop you from deleting beyond a certain point. This occurs because when a character is deleted from the middle, the remaining characters shift left. If the characters are of different element types, the textbox does not allow this shift, preventing further deletion.
For example, consider the Mask=” (999)-000-0000”. In this masking, the element type of all the characters is same, that is, digit. So, the deletion can take place easily from any position in the masked textbox, that is, from extreme right, left or middle of characters.
Consider another example where the mask is set to "LL:####:00.A###". If you enter the value "AB:1234:56.7890" into the masked textbox and attempt to delete one of the letters, such as 'A' or 'B', the textbox will prevent this action. This restriction occurs because, upon deletion, the number '1' would need to shift left to occupy the position of the deleted letter. However, due to the masking rules, that position is reserved exclusively for letters (A-Z), so the masked textbox blocks the deletion to maintain the input's format.
In conclusion, the masked textbox restricts the deletion of characters whenever a character would need to move into a position reserved for a different element type. This ensures that the integrity of the input format is maintained, preventing characters from occupying positions meant for other types.
