[c#] Remove the title bar in Windows Forms

How can I remove the blue border that's on top of the Window Form? (I don't know the name of it exactly.)

 Me.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None

if by Blue Border thats on top of the Window Form you mean titlebar, set Forms ControlBox property to false and Text property to empty string ("").

here's a snippet:

this.ControlBox = false;
this.Text = String.Empty;

I am sharing my code. form1.cs:-

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

    private void Form1_Load(object sender, EventArgs e)
    {
        FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;

    }

    private void ExitClick(object sender, EventArgs e)
    {
        Application.Exit();
    }

    private void MaxClick(object sender, EventArgs e)
    {
        if (WindowState ==FormWindowState.Normal)
        {
            this.WindowState = FormWindowState.Maximized;
        }
        else
        {
            this.WindowState = FormWindowState.Normal;
        }
    }

    private void MinClick(object sender, EventArgs e)
    {
        this.WindowState = FormWindowState.Minimized;
       }
    }
    }

Now, the designer:-

namespace BorderExp
 {
   partial class Form1
  {
    /// <summary>
    /// Required designer variable.
    /// </summary>
    private System.ComponentModel.IContainer components = null;

    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Dispose(disposing);
    }

    #region Windows Form Designer generated code

    /// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    {
        this.button1 = new System.Windows.Forms.Button();
        this.button2 = new System.Windows.Forms.Button();
        this.button3 = new System.Windows.Forms.Button();
        this.SuspendLayout();
        // 
        // button1
        // 
        this.button1.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
        this.button1.BackColor = System.Drawing.SystemColors.ButtonFace;
        this.button1.BackgroundImage = global::BorderExp.Properties.Resources.blank_1_;
        this.button1.FlatAppearance.BorderSize = 0;
        this.button1.FlatAppearance.MouseOverBackColor = System.Drawing.Color.FromArgb(((int)(((byte)(224)))), ((int)(((byte)(224)))), ((int)(((byte)(224)))));
        this.button1.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
        this.button1.Location = new System.Drawing.Point(376, 1);
        this.button1.Name = "button1";
        this.button1.Size = new System.Drawing.Size(27, 26);
        this.button1.TabIndex = 0;
        this.button1.Text = "X";
        this.button1.UseVisualStyleBackColor = false;
        this.button1.Click += new System.EventHandler(this.ExitClick);
        // 
        // button2
        // 
        this.button2.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
        this.button2.BackColor = System.Drawing.SystemColors.ButtonFace;
        this.button2.BackgroundImage = global::BorderExp.Properties.Resources.blank_1_;
        this.button2.FlatAppearance.BorderSize = 0;
        this.button2.FlatAppearance.MouseOverBackColor = System.Drawing.Color.FromArgb(((int)(((byte)(224)))), ((int)(((byte)(224)))), ((int)(((byte)(224)))));
        this.button2.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
        this.button2.Location = new System.Drawing.Point(343, 1);
        this.button2.Name = "button2";
        this.button2.Size = new System.Drawing.Size(27, 26);
        this.button2.TabIndex = 1;
        this.button2.Text = "[]";
        this.button2.UseVisualStyleBackColor = false;
        this.button2.Click += new System.EventHandler(this.MaxClick);
        // 
        // button3
        // 
        this.button3.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
        this.button3.BackColor = System.Drawing.SystemColors.ButtonFace;
        this.button3.BackgroundImage = global::BorderExp.Properties.Resources.blank_1_;
        this.button3.FlatAppearance.BorderSize = 0;
        this.button3.FlatAppearance.MouseOverBackColor = System.Drawing.Color.FromArgb(((int)(((byte)(224)))), ((int)(((byte)(224)))), ((int)(((byte)(224)))));
        this.button3.FlatStyle = System.Windows.Forms.FlatStyle.Flat;
        this.button3.Location = new System.Drawing.Point(310, 1);
        this.button3.Name = "button3";
        this.button3.Size = new System.Drawing.Size(27, 26);
        this.button3.TabIndex = 2;
        this.button3.Text = "___";
        this.button3.UseVisualStyleBackColor = false;
        this.button3.Click += new System.EventHandler(this.MinClick);
        // 
        // Form1
        // 
        this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
        this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
        this.BackgroundImage = global::BorderExp.Properties.Resources.blank_1_;
        this.ClientSize = new System.Drawing.Size(403, 320);
        this.ControlBox = false;
        this.Controls.Add(this.button3);
        this.Controls.Add(this.button2);
        this.Controls.Add(this.button1);
        this.Name = "Form1";
        this.StartPosition = System.Windows.Forms.FormStartPosition.CenterScreen;
        this.Text = "Form1";
        this.Load += new System.EventHandler(this.Form1_Load);
        this.ResumeLayout(false);

    }

    #endregion

    private System.Windows.Forms.Button button1;
    private System.Windows.Forms.Button button2;
    private System.Windows.Forms.Button button3;
    }
   }

the screenshot:- NoBorderForm

You can set the Property FormBorderStyle to none in the designer, or in code:

this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;

Also add this bit of code to your form to allow it to be draggable still.

Just add it right before the constructor (the method that calls InitializeComponent()

private const int WM_NCHITTEST = 0x84;
private const int HTCLIENT = 0x1;
private const int HTCAPTION = 0x2;

///
/// Handling the window messages
///
protected override void WndProc(ref Message message)
{
    base.WndProc(ref message);

    if (message.Msg == WM_NCHITTEST && (int)message.Result == HTCLIENT)
        message.Result = (IntPtr)HTCAPTION;
}

That code is from: https://jachman.wordpress.com/2006/06/08/enhanced-drag-and-move-winforms-without-having-a-titlebar/

Now to get rid of the title bar but still have a border combine the code from the other response:

this.ControlBox = false;

this.Text = String.Empty;

with this line:

this.FormBorderStyle = FormBorderStyle.FixedSingle;

Put those 3 lines of code into the form's OnLoad event and you should have a nice 'floating' form that is draggable with a thin border (use FormBorderStyle.None if you want no border).

Set FormsBorderStyle of the Form to None.

If you do, it's up to you how to implement the dragging and closing functionality of the window.