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How do you convert your bool to a bit (1 or 0) value?

Posted in .Net, C#, Development at November 24th, 2008 by Ben / 4 Comments »

I’ve often seen code that tries to get a numeric bit (1, 0) value for a boolean.

I know of three ways you can do it:

  1. Manual condition checking
  2. Use the GetHashCode() method
  3. Use the built in .Net Convert class

All three approaches do the job however I find that using the Convert.ToByte(boolValue) makes the most sense from a readability stance.

The following examples mix it up a bit and accommodate a Nullable<bool>.

Let’s start with the scenario where true is 1 and false and null are 0.


   bool? tVal = true;
    bool? fVal = false;
    bool? nVal = null;

    // true = 1, false = 0, null = 0

    Assert.AreEqual(1, tVal.HasValue && tVal.Value ? 1 : 0);
    Assert.AreEqual(0, fVal.HasValue && fVal.Value ? 1 : 0);
    Assert.AreEqual(0, nVal.HasValue && nVal.Value ? 1 : 0);

    Assert.AreEqual(1, tVal.GetHashCode());
    Assert.AreEqual(0, fVal.GetHashCode());
    Assert.AreEqual(0, nVal.GetHashCode());

    Assert.AreEqual(1, Convert.ToByte(tVal));
    Assert.AreEqual(0, Convert.ToByte(fVal));
    Assert.AreEqual(0, Convert.ToByte(nVal));

Now let’s mix it up a bit and say that a null value should represent a TRUE or 1 value by default.
i.e. true = 1, null = 1, false = 0, 



    bool? tVal = true;
    bool? fVal = false;
    bool? nVal = null;

    Assert.AreEqual(1, !tVal.HasValue || tVal.Value ? 1 : 0);
    Assert.AreEqual(0, !fVal.HasValue || fVal.Value ? 1 : 0);
    Assert.AreEqual(1, !nVal.HasValue || nVal.Value ? 1 : 0);

    Assert.AreEqual(1, (tVal ?? true).GetHashCode());
    Assert.AreEqual(0, (fVal ?? true).GetHashCode());
    Assert.AreEqual(1, (nVal ?? true).GetHashCode());

    Assert.AreEqual(1, Convert.ToByte(tVal ?? true));
    Assert.AreEqual(0, Convert.ToByte(fVal ?? true));
    Assert.AreEqual(1, Convert.ToByte(nVal ?? true));

Is there an easier, better or another alternate way to do this?

I’d love to hear your thoughts?

Published in .Net, C#, Development

4 Responses to “How do you convert your bool to a bit (1 or 0) value?”

  1. November 24th, 2008 at 9:09 am #gerrod

    It depends on why you’re doing the conversion.

    If it’s simply to pass in to a byte field in the database, you can just pass it as a boolean and let the framework handle the conversion for you. Not sure how this works with a nullable bool and a NULL DB field, though…

    But in general I think I’d go with the Convert.ToByte as well; that’s my usual fallback when there is no implicit (/explicit) cast operator defined.

  2. November 24th, 2008 at 8:24 pm #Ben

    Quite correct young man when dealing with a DB, however this scenario was not the impetus for such an article.

  3. July 21st, 2009 at 7:07 pm #Igor

    byte /*or int*/ v = 1;
    bool b = Convert.ToBoolean(v);

  4. November 3rd, 2009 at 3:02 am #GP

    Here’s something I use-

    bool boolvariable = args.Length > 0 ? int.TryParse(args[0], out outnum) ? Convert.ToBoolean(Convert.ToByte(args[0])) : Convert.ToBoolean(args[0]) : true;

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