C# - MaskedTextBox Class

In C#, the MaskedTextBox class control provides a validation procedure for the user input on the form, like date, phone numbers, etc. It provides a mask to enforce valid input formats. The MaskedTextBox class in C# is used to represent the Windows masked text box and also provides different types of properties, methods, and events. It is defined under System.Windows.Forms namespace.

What is MaskedTextBox?

This class-enhanced version of the TextBox control supports a declarative syntax for receiving or rejecting the user input, and when this control displays at run time, it represents the mask as a sequence of prompt characters and optional literal characters.

Use Cases of MaskedTextBox:

The use cases of MaskedTextBox are listed below:

• Input Validation: MaskedTextBox enforces input patterns. For example, to accept only numeric values for age.
• User-Friendly: It visually appears good and helps user to identify which kind of input needs to be filled out.
• Customizable Masks: We can also create custom masks for different kinds of specific input fields as per the requirements.

Ways to Create a MaskedTextBox In Windows Forms

There are mainly two ways to create a MaskedTextBox in Windows forms, which are mentioned below.

• Drag and drop (Design-Time)
• Custom MaskedTextBox (Run-Time)

1. Drag and Drop (Design-Time)

This is the easiest way to create a MaskedTextBox in Windows Forms using Visual Studio we just have to open the toolbox and drag and drop the button on the form in the designer, and further we can change the appearance of the MaskedTextBox using the properties.

Follow these steps to create a MaskedTextBox.

Step 1: Now locate the project with the name here we are using the default name which is Form1 and it will open a form in the editor that we can further modify.

In the image, we have two files that are open one Design and there is Form1.cs these two play a major role. We use the Form 1.cs file for the custom logic.

Step 2: Now open a Toolbox go to the view > Toolbox or ctrl + alt + x.

Step 3. Now open the common controls and drag and drop the MaskedTextBox on the form where we want to it be placed.

Step 4: Now open the properties of the button Right-click on the MaskedTextBox to open the Properties window, where you can customize its appearance and behavior.

In the properties, we can add different types of input text such as date and time.

Output:

2. Custom MaskedTextBox (Run Time)

In this method, we are going to modify Form1.cs file and add custom code modification in C# with the help of the MaskedTextBox class.

The following steps show how to create a MaskedTextBox dynamically:

Step 1: Create a MaskedTextBox control using the MaskedTextBox() constructor provided by the MaskedTextBox class.

// Creating a MaskedTextBox control

MaskedTextBox mbox = new MaskedTextBox();

Step 2: After creating the MaskedTextBox control, set the property of the MaskedTextBox control provided by the MaskedTextBox class.

// Setting the properties

// of MaskedTextBox

mbox.Location = new Point(374, 137);

mbox.Mask = "000000000";

mbox.Size = new Size(176, 20);

mbox.Name = "MyBox";

mbox.Font = new Font("Bauhaus 93", 18);

Step 3: And lastly add this MaskedTextBox control to the form using the following statement:

// Adding MaskedTextBox

// control on the form

this.Controls.Add(mbox);

Step 4: Now double-click on the form in Design and it will open the Form1.cs file where code is written in C#. Here the program file is Form 1.cs Now write this code in Form1.cs file

Form1.cs file:

namespace WinFormsApp1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // Creating and setting the
            // properties of the Label
            Label l1 = new Label();
            l1.Location = new Point(413, 98);
            l1.Size = new Size(176, 20);
            l1.Text = " Example";
            l1.Font = new Font("Bauhaus 93", 12);

            // Adding label on the form
            this.Controls.Add(l1);

            // Creating and setting the
            // properties of the Label
            Label l2 = new Label();
            l2.Location = new Point(242, 135);
            l2.Size = new Size(126, 20);
            l2.Text = "Phone number:";
            l2.Font = new Font("Bauhaus 93", 12);

            // Adding label on the form
            this.Controls.Add(l2);

            // Creating and setting the
            // properties of the MaskedTextBox
            MaskedTextBox mbox = new MaskedTextBox();
            mbox.Location = new Point(374, 137);
            mbox.Mask = "000000000";
            mbox.Size = new Size(176, 20);
            mbox.Name = "MyBox";
            mbox.Font = new Font("Bauhaus 93", 18);

            // Adding MaskedTextBox
            // control on the form
            this.Controls.Add(mbox);
        }

    }
}

Output:

Constructor

This class consists of three constructors, with the help of which we can create objects of this class in different ways. The following are the constructors available in this class:

Properties

The properties of this class is listed below:

Troubleshooting Tips and Best Practices

• Always make sure the PromptChar is easy to see, this will help user to know where they need to enter the data.
• When creating mask pattern always think about how long the input should be and its format. This helps users to avoid mistakes.
• If we can not see the MaskedTextBox, check its location and size settings to make sure it is placed and sized properly.