An object reference is required for the nonstatic field, method, or property 'WindowsApplication1.Form1.setTextboxText(int)
<pre><code>namespace WindowsApplication1
{

    public partial class Form1 : Form
    {


        public Form1()
        {
            InitializeComponent();

        }

        private void button1_Click(object sender, EventArgs e)
        {

            //int[] val ={ 0, 0 };
            int val;
            if (textBox1.Text == "")
            { MessageBox.Show("Input any no"); }
            else
            {
                val = Convert.ToInt32(textBox1.Text);

                Thread ot1 = new Thread(new ParameterizedThreadStart(SumData));
                ot1.Start(val);

                }


        }
        private static void ReadData(object state)
        {
            System.Windows.Forms.Application.Run(); 
        }



        void setTextboxText(int result)
        {
            if (this.InvokeRequired)
            { this.Invoke(new IntDelegate(SetTextboxTextSafe), new object[] { result }); }
            else
            {
                SetTextboxTextSafe(result);
            }

        }
        void SetTextboxTextSafe(int result)
        {
            label1.Text = result.ToString();
        }

        private static void SumData(object state)
        {
            int result;
            //int[] icount = (int[])state;
            int icount = (int)state;

            for (int i = icount; i &gt; 0; i--)
            {
                result += i;
                System.Threading.Thread.Sleep(1000);
            }
         setTextboxText(result);



        }
        delegate void IntDelegate(int result);
        private void button2_Click(object sender, EventArgs e)
        {
            Application.Exit();
        }
    }
}
</code></pre>

<p>Could anyone gave me the answer why this error is occuring
An object reference is required for the nonstatic field, method, or property 'WindowsApplication1.Form1.setTextboxText(int)</p>
