C# bitmask validation

I have a small problem with bitmask validation as below:

...
if (BitExist("52","0x20"))
{
 //do something
}
...
...

Private bool BitExist(String value, String key)
{
  //how can i make it return true?
}

开发者_如何转开发

My main problem is that, the value & key is a string value. Is there an easy way to make this works? I'm very new to this bitmask thingy. Really appreciate it if someone can help me out.

---

private bool BitExists(string value, string key)
{
    int k = Int32.Parse(key, System.Globalization.NumberStyles.AllowHexSpecifier);
    return (Int32.Parse(value) & k) == k;
}

What this code snippet does is the following. Inside the bracket the one bit described by key is isolated.

 00110100
&00100000
---------
 00100000

After that you have you have to determine whether or not the isolated bit is checked:

00100000 == 00100000 = true