MaskedTextBox is an advanced textbox control which automatically validates the input entered by a user. When a MaskedTextBox is added to a form, it exists as a completely functional text box which includes a basic text input area and can be further customized with a mask. The desired mask can be set by using EditMask property of the C1MaskedTextBox class.

this.c1MaskedTextBox1 = new C1.Win.Input.C1MaskedTextBox();
((System.ComponentModel.ISupportInitialize)(this.c1MaskedTextBox1)).BeginInit();
this.c1MaskedTextBox1.Location = new System.Drawing.Point(7, 26);
this.c1MaskedTextBox1.Name = "c1MaskedTextBox1";
this.c1MaskedTextBox1.Size = new System.Drawing.Size(100, 25);

Mask Types

You can apply different types of masks to the MaskedTextBox control by specifying the following placeholders to the EditMask property. Once the mask is applied, the input entered by a user will be validated and invalid characters will not be allowed in the control: 

Apart from the above placeholders, regular expressions can also be defined in the MaskedTextBox. The following keywords can be defined in regular expressions:

Mask Settings

You can set the desired mask to MaskedTextBox control by setting the EditMask property to a mask string. On defining an edit mask, each character position in the control maps to either a special placeholder or a literal character. Literal characters, or literals, can give visual cues about the type of data being used. For example, the parenthesis surrounding the area code of a telephone number and dashes are literals: +1-(412)-123-4567.

Although setting EditMask property is enough in simple cases, there is also a MaskInfo property containing sub-properties controlling various important aspects of masked input. A few of these sub-properties are CustomPlaceholders, PromptChar, RegexpEditMask, ErrorMessage, ShowLiterals etc.

The phone number in the above image is represented with a mask where EditMask is set to "+0-(000)-000-0000"

this.c1MaskedTextBox1.EditMask = "-(000)-000-0000";
this.c1MaskedTextBox1.MaskInfo.PromptChar = '#';

Further, you can also set the mask expression style using RegexpMaskType property of the MaskInfo class. The RegexpMaskType property uses the RegexpMaskType enumeration to determine the RegexpEditMask pattern processing and validation by accepting one of the following two values:

• C1RegexpEditMask - Uses a custom parser and does not support complicated regular expressions. It provides an edit mask for the user input and can be validated while entering the text.
• RegexpMask - It is based on MS Regex with some restrictions for available keywords. It does not provide any edit mask and can be validated on exit from the edit mode only.

The code snippet below shows how to set the RegexpMaskType property:

//set the Regexptype
c1MaskedTextBox1.MaskInfo.RegexpMaskType = C1.Win.Input.Formating.RegexpMaskType.C1RegexpEditMask;
//set the regex mask
c1MaskedTextBox1.MaskInfo.RegexpEditMask = "[1-9]{1}[0-9]{9}";

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Prompt Characters and Literals

With the MaskedTextBox control, you can choose to show prompt characters and literals.

The prompt character is the text that appears in the control (like # or _)and prompts the user to enter the text. You can choose to include prompt characters in the MaskedTextBox control by setting PromptChar property.

Literals are non-mask characters that appear as themselves within the mask, like / or -. Literals always occupy a static position in the mask at run time, and cannot be moved or deleted by the user.

For example, in the below image, the EditMask property is set to "000-0000" to define a zip code. Here, the mask character include the "0" element, the "-" is a literal and "#" is a prompt character.

this.c1MaskedTextBox1.EditMask = "000-0000";
this.c1MaskedTextBox1.MaskInfo.PromptChar = '#';

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Placeholder Text

The placeholder text provides hint about what value a user should enter in a control. MaskedTextBox lets you display a placeholder text in the control when nothing is selected or entered in it by using Placeholder property of the C1MaskedTextBox class. When you click within the control and enter text, the Placeholder text disappears.

For example, the following image shows "Enter Phone Number" as a placeholder text in the MaskedtextBox control which hints the user to enter a phone number. 

this.c1MaskedTextBox1.Placeholder = "Enter Phone Number";

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Password

User can set a password of desired length and characters in a MaskedTextBox control and can use UseSystemPasswordChar property which ensures that the system-supplied password character is used.

this.c1MaskedTextBox4.UseSystemPasswordChar = true;
this.c1MaskedTextBox4.MaskInfo.EditMask = "AAAAAAAAaaaa";

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Maximum Character Length

You can limit the number of characters which can be entered in the control by specifying the desired number of characters in the EditMask property. For example, the below image shows Zip code of an area where maximum limit is 7 digits.

this.c1MaskedTextBox1.EditMask = "000-0000";

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Display and Edit Format

MaskedTextBox allows you to specify two different formats, one for display (when the control is read-only or is not in the edit mode), and another for edit mode. These two formatting modes are governed by the DisplayFormat and EditFormat properties.

this.c1MaskedTextBox1.DisplayFormat.FormatType = FormatType.LongDate;
this.c1MaskedTextBox3.EditFormat.FormatType = FormatType.ShortDate;

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Multiline MaskedTextBox

A MaskedTextBox can be converted into a multiline MaskedTextbox by using the Multiline property. This is particularly useful in cases where a considerable amount of data needs to be entered in the textbox, like an address or a customized choice.

this.c1MaskedTextBox1.Multiline = true;

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