The masked text box allows you to configure one or more placeholders in the field of the control so that the control can accept some characters, must reject some characters, and/or can display some other characters you will have put so the user cannot delete them.

To create a masked text box, from the Common Controls section of the Toolbox, you can click MaskedTextBox and click the form. To programmatically create a masked text box, declare a variable of type MaskedTextBox, use the gcnew operator to initialize it, and add it to the Controls collection of its container. Here is an example:

#include <windows.h>

#using <System.dll>
#using <System.Drawing.dll>
#using <System.Windows.Forms.dll>

using namespace System;
using namespace System::Drawing;
using namespace System::Windows::Forms;

public ref class CExercise : Form
{
private:
    MaskedTextBox ^ txtFunctional;

public:
    CExercise()
    {
        InitializeComponent();
    }
	
private:
    void InitializeComponent()
    {
        txtFunctional = gcnew MaskedTextBox;

        Controls->Add(txtFunctional);

	Text = "Functional";
    }
};

[STAThread]
int APIENTRY WinMain(HINSTANCE hInstance,
		     HINSTANCE hPrevInstance,
		     LPSTR lpCmdLine,
		     int nCmdShow)
{
    Application::Run(gcnew CExercise);

    return 0;
}

The masked text box uses the same common characteristics of other visual control: location, size, etc.

The masked text box uses the same common characteristics of other visual control: name, location, size, background color, border size, anchoring, docking, font, etc. Like the regular text box, the MaskedTextBox class is derived from TextBoxBase that provides its fundamental properties. This means that with the masked text box, you can cut or copy text from it, you can paste text to it, you can measure the length of its text, you can select some part of its text from a specific position to another, or you can select all of its text. Like the regular text box, the masked text box uses the AsciiOnly property, which indicates whether the control should accept or allow only ASCII characters.

The primary reason for using a masked text box is to control short lengths of text entered into it. For this reason, you should not consider some of the multi-line characteristics of a regular text box: word wrapping, scroll bars, the ability to use the Tab key inside the control, etc.

Probably the most important property of a masked text box, which sets it apart from the (traditional) text box control, is its ability to control what the user can and cannot enter in the text side. To visually configure this text, the MaskedTextBox class is equipped with a property named Mask:

public:
    property String^ Mask
    {
        String^ get ();
        void set (String^ value);
    }

There are two main ways you can configure it:

• If you already know the mask you want to use, access the Properties window for the control and, in the Mask field, type the right formula
• If you do not know or are not sure, in the Properties window for the control
  • Click Mask and click its ellipsis button
  • On the form, click the control and, under the Properties window, click Set Mask... This would open the Input Mask dialog box
  • On the form, click the control, click the arrow button on it, and click Edit Mask...
     
    

Any of these actions would open the Input Mask dialog box:

The Input Mask dialog box provides some of the most regularly used masks in Windows and database applications (the contents of the Input Mask dialog box depends on the language settings of the computer on which you are using Microsoft Visual Studio. For example, the above Input Box is adapted for US English with the US Social Security Number and telephone format). To use an existing mask, you can click it and click OK.

If none of the masks in the list suits you, you can create your own. In the Input Mask dialog box, you can click <Custom>, click the masked text box, create the format, and click OK. Or, in the Properties window for the masked text box, you can click the Mask field and create your mask. To create a mask, you use some characters and combine them as you see fit. The characters you can use are:

To programmatically specify a mask, create it in a string and assign that string to the Mask property. Here is an example:

void InitializeComponent()
{
    txtFunctional = gcnew MaskedTextBox;
    txtFunctional->Location = Point(12, 12);
        
    txtFunctional->Mask = "999-000-0000";

    Controls->Add(txtFunctional);

    Text = "Mask Text Box";
}

This would produce:

When you create a mask, to indicate a placeholder for a letter, a digit, or a symbol, the control uses a specific character. The default character is the underscore. If you want, you can use a different character. To support this, the MaskedTextBox class is equipped with the PromptChar property, which is of type char:

public:
    property wchar_t PromptChar
    {
        wchar_t get ();
        void set (wchar_t value);
    }

To change it visually, access the Properties window for the control, click PromptChar and type the desired character. To programmatically specify the character of the placeholders, assign a string to the PromptChar property.