How to Style the Border of the RichTextBox in C#?

In C#, RichTextBox control is a textbox which gives you rich text editing controls and advanced formatting features also includes a loading rich text format (RTF) files. Or in other words, RichTextBox controls allows you to display or edit flow content, including paragraphs, images, tables, etc. In RichTextBox, you are allowed to style the border of the RichTextBox control using BorderStyle Property. This property has three different values that are defined under BorderStyle enum and the values are:

• None value for no border.
• Fixed3D value for 3-D border.
• FixedSingle value for single line border.

The default value of this property is Fixed3D. You can set this property in two different ways:

1. Design-Time: It is the easiest way to style the border of the RichTextBox as shown in the following steps:

• Step 1: Create a windows form as shown in the below image:
  Visual Studio -> File -> New -> Project -> WindowsFormApp
  
• Step 2: Next, drag and drop the RichTextBox control from the toolbox to the form as shown in the below image:

  

• Step 3: After drag and drop you will go to the properties of the RichTextBox and style the border of the RichTextBox as shown in the below image:

  

  
  
  

  Output:

  

2. Run-Time: It is a little bit trickier than the above method. In this method, you can style the border of the RichTextBox control programmatically with the help of given syntax:

public string Name { get; set; }

Here, BorderStyle represents the border style of the RichTextBox control. It will throw an InvalidEnumArgumentException if the value of this property does not belong to BorderStyle enum values. The following steps show how to style the border of the RichTextBox dynamically:

• Step 1: Create a RichTextBox using the RichTextBox() constructor is provided by the RichTextBox class.

  // Creating a RichTextBox
  RichTextBox rbox = new RichTextBox();
  

• Step 2: After creating RichTextBox, set the BorderStyle property of the RichTextBox provided by the RichTextBox class.

  // Setting the border style
  rbox.BorderStyle = BorderStyle.FixedSingle;
  

• Step 3: And last add this RichTextBox control to the form using the following statement:

  // Adding a RichTextBox
  // control to the form
  this.Controls.Add(rbox);
  

Example:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp51 {

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 lb = new Label();
        lb.Location = new Point(251, 70);
        lb.Text = "Enter Introduction";

        // Adding this label in the form
        this.Controls.Add(lb);

        // Creating and setting the
        // properties of RichTextBox
        RichTextBox rbox = new RichTextBox();
        rbox.Location = new Point(236, 97);
        rbox.Size = new Size(278, 115);
        rbox.BorderStyle = BorderStyle.FixedSingle;
        rbox.ForeColor = Color.Green;
        rbox.Text = "Welcome to GeeksforGeeks Portal";

        // Adding this RichTextBox
        // in the form
        this.Controls.Add(rbox);
    }
}
}

Output: