To identify the load - from button click or refresh
<p>I have a button in my page which does some transaction in my database.</p>

<p>Currently, I am facing a problem: </p>

<ul>
<li>If I click the button it posts back the page and it goes into <code>button_Click(object sender, EventArgs e)</code> and  does the transaction <strong>which is okay for me</strong>.</li>
<li>If I refresh the page , it again goes into <code>button_Click(object sender, EventArgs e)</code> which is not desirable.</li>
</ul>

<p>How can I determine if the user has refreshed the page and avoid duplicating the transaction?</p>

<p>Thanks in advance.</p>
