将TataTable转换为json字符

 DataTable table = new DataTable();
            table.Columns.Add("ID", typeof(string));
            table.Columns.Add("Name", typeof(string));
            for (int i = 0; i < 100; i++)
            {
                DataRow row = table.NewRow();
                row["ID"] = i.ToString();
                row["Name"] = "张三" + i.ToString();
                table.Rows.Add(row);
            }

            dataGridView1.DataSource = table;
            var json = JsonConvert.SerializeObject(table);