Double Click in Datagridview

public  string strvalue = string.Empty;
        public Form2()
        {
            InitializeComponent();
        }
        public Form2(string str)
        {
            strvalue = str;
            InitializeComponent();
        }

private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            if (e.RowIndex != -1)
            {
                if (e.ColumnIndex != 1)
                {
                    if (!string.IsNullOrEmpty(dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString()))
                    {
                        string strValue = dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value.ToString();
                        Form2 _Form2 = new Form2(strValue);
                        _Form2.ShowDialog();
                        dataGridView1.Rows[e.RowIndex].Cells[e.ColumnIndex].Value = _Form2.strvalue;
                        dataGridView1.Refresh();
                    }
                }
            }
        }

private void button1_Click(object sender, EventArgs e)
       {
           strvalue = textBox1.Text;
           this.Close();
       }