How to clear Textbox

using System;
using System.Windows.Forms;

namespace ClearTextbox
{
    static class Program
    {
        static void Main()
        {
            // Create a form
            Form form = new Form();
            // ... and a Textbox
            TextBox textbox = new TextBox();
            textbox.Dock = DockStyle.Top;
            textbox.Text = "Clear me!";
            // Let's say you have a button "Clear"
            Button buttonClear = new Button();
            buttonClear.Text = "Clear";
            buttonClear.Dock = DockStyle.Top;
            // ... and maybe on Click
            buttonClear.Click += delegate(object sender, EventArgs e)
            {
                // you clear the TextBox
                textbox.Clear(); 
            };

            // Add the 2 Controls to the Form
            form.Controls.Add(buttonClear);
            form.Controls.Add(textbox);
            // ... and run it
            Application.Run(form);
        }
    }
}

textbox1.Clear();

textbox1.text=string.empty;

textbox1.Text = "" ;

textbox1.text="";

textbox1.text=string.empty;