help in TabControl

int i = 0;
        private void btnext_Click(object sender, EventArgs e)
        {
            if (i <= 3)  //using 3 A/c to your question you can change it
            {
                tabControl1.SelectedIndex = i;
                tabControl1.TabPages[i].Parent.Focus();
                i++;    // Increase counter
            }
            else
            {
             //you Message
            }
        }

private void btnNext_Click(object sender, EventArgs e)
        {
            int NumIndex = tabControl1.SelectedIndex;
            if (NumIndex < tabControl1.TabPages.Count-1)
            {
                tabControl1.SelectTab(NumIndex + 1);
            }
        }