How to check if an appSettings key exists?

Question

How do I check to see if an Application Setting is available?

i.e. app.config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <appSettings>
    <add key ="someKey" value="someValue"/>
  </appSettings>
</configuration>

and in the codefile

if (ConfigurationManager.AppSettings.ContainsKey("someKey"))
{
  // Do Something
}else{
  // Do Something Else
}

Answer 1

Upper options gives flexible to all manner, if you know key type try parsing them bool.TryParse(ConfigurationManager.AppSettings["myKey"], out myvariable);