Can .NET convert “Yes” & “No” to boolean without If?

Question

You would think there would be a way using DirectCast, TryCast, CType etc but all of them seem to choke on it e.g.:

CType(\"Yes\", Boolean)

Answer 1

private static bool GetBool(string condition)
{
    return condition.ToLower() == "yes";
}

GetBool("Yes"); // true
GetBool("No"); // false

Or another approach using extension methods

public static bool ToBoolean(this string str)
{
    return str.ToLower() == "yes";
}

bool answer = "Yes".ToBoolean(); // true
bool answer = "AnythingOtherThanYes".ToBoolean(); // false

Answer 2

C# 6+ version:

public static bool StringToBool(string value) => 
    value.Equals("yes",           StringComparison.CurrentCultureIgnoreCase) ||
    value.Equals(bool.TrueString, StringComparison.CurrentCultureIgnoreCase) || 
    value.Equals("1");`

Answer 3

If you think about it, "yes" cannot be converted to bool because it is a language and context specific string.

"Yes" is not synonymous with true (especially when your wife says it...!). For things like that you need to convert it yourself; "yes" means "true", "mmmm yeeessss" means "half true, half false, maybe", etc.

Answer 4

Using this way, you can define conversions from any string you like, to the boolean value you need. 1 is true, 0 is false, obviously.
Benefits: Easily modified. You can add new aliases or remove them very easily.
Cons: Will probably take longer than a simple if. (But if you have multiple alises, it will get hairy)

enum BooleanAliases {
      Yes = 1,
      Aye = 1,
      Cool = 1,
      Naw = 0,
      No = 0
 }
 static bool FromString(string str) {
      return Convert.ToBoolean(Enum.Parse(typeof(BooleanAliases), str));
 }
 // FromString("Yes") = true
 // FromString("No") = false
 // FromString("Cool") = true

Answer 5

Slightly off topic, but I needed once for one of my classes to display 'Yes/No' instead of 'True/False' in a property grid, so I've implemented YesNoBooleanConverter derived from BooleanConverter and decorating my property with <TypeConverter(GetType(YesNoBooleanConverter))> _...

Answer 6

I like the answer that @thelost posted, but I'm reading values from an ADO.Net DataTable and the casing of the string in the DataTable can vary.

The value I need to get as a boolean is in a DataTable named childAccounts in a column named Trades.

I implemented a solution like this:

bool tradeFlag = childAccounts["Trade"].ToString().Equals("yes", StringComparison.InvariantCultureIgnoreCase);