In your project you should have a app.config file with a section similar to this:
<applicationSettings>
<WindowsFormsApplication1.Properties.Settings>
<setting name="SecurityKey" serializeAs="String">
<value>Hello</value>
</setting>
</WindowsFormsApplication1.Properties.Settings>
</applicationSettings>
Auto-generated files called Settings.settings and Settings.Designer.cs should have been created.
They will allow you to access the setting like this:
private void button1_Click(object sender, EventArgs e)
{
String Security = WindowsFormsApplication1.Properties.Settings.Default.SecurityKey;
}
If you go to Project, Properties, Settings you will see a button that says Synchronize. Clicking that sometimes gets everything refreshed (when things get funky).