private void newBlock_Click(object sender, EventArgs e)
{
System.Diagnostics.Debug.WriteLine("hello " + comboBox1.SelectedIndex);
//List<Transaction> transactions = blockchain.getPendingTransactions();
List <Transaction> transactions = blockchain.gettransactionPool(comboBox1.SelectedIndex, publicKey.Text);
//System.Diagnostics.Debug.WriteLine(transactions[0].fee);
Block newBlock = new Block(blockchain.GetLastBlock(), transactions, _Form1, publicKey.Text);
blockchain.Blocks.Add(newBlock);
richTextBox1.Text = blockchain.ToString();
}