navigate records in datagridview

Below is the code which will show how to navigate between datagridview records like first, last, previous and next record. 
     
        private void button1_Click(object sender, EventArgs e)
        {
            //first
            int i = 0;
            this.dataGridView1.CurrentCell = dataGridView1.Rows[0].Cells[dataGridView1.CurrentCell.ColumnIndex];
        }

        private void button2_Click(object sender, EventArgs e)
        {
            //previous
            int prev = dataGridView1.CurrentRow.Index - 1;
            if (prev >= 0)
            {
                this.dataGridView1.CurrentCell = dataGridView1.Rows[prev].Cells[dataGridView1.CurrentCell.ColumnIndex];
                //MessageBox.Show(dataGridView1[0, dataGridView1.CurrentRow.Index].Value.ToString());
            }
        }

        private void button3_Click(object sender, EventArgs e)
        {
            // Next
            int next = dataGridView1.CurrentRow.Index + 1;
            if (next < dataGridView1.Rows.Count)
            {
                this.dataGridView1.CurrentCell = dataGridView1.Rows[next].Cells[dataGridView1.CurrentCell.ColumnIndex];
                //MessageBox.Show(dataGridView1[0, dataGridView1.CurrentRow.Index].Value.ToString());
            }
        }

        private void button4_Click(object sender, EventArgs e)
        {
            //last
            int i = dataGridView1.Rows.Count - 1;
            if (i < dataGridView1.Rows.Count)
            {
                this.dataGridView1.CurrentCell = dataGridView1.Rows[i].Cells[dataGridView1.CurrentCell.ColumnIndex];
                //MessageBox.Show(dataGridView1[0, dataGridView1.CurrentRow.Index].Value.ToString());
            }

        }