C# How do I check if one of two values is TRUE?
Should be a simple question for the C# experts here.
I basically want to check if one value or another is TRUE, a wild stab at the code is below:
if ((Boolean.Parse(staff.getValue("Male")) | Boolean.P开发者_运维知识库arse(staff.getValue("Female")))
{
// is true
}
Is this correct?
Thanks
If EXACTLY ONE should be true then it is:
var male = bool.Parse(staff.getValue("Male"));
var female = bool.Parse(staff.getValue("Female"));
if (male ^ female)
{
//is true
}
Sounds like you're looking for the logical OR.
if(condition1 || condition2)
{
}
Use the ||
(double pipe), logical OR.
bool isMale = Boolean.Parse(staff.getValue("Male");
bool isFemale = Boolean.Parse(staff.getValue("Female");
if (isMale || isFemale) // note double pipe ||
{
// do something if true
}
In C# statement expressions are evaluated from left to right. In an OR operation, the second expression will not be evaluated if the first one equals true.
The conditional OR operator ||
is what you need
if ((Boolean.Parse(staff.getValue("Male")) || Boolean.Parse(staff.getValue("Female")))
{
//is true
}
If the first condition is TRUE
, then the second condition isn't checked since the outcome is obviously going to return TRUE
.
Note that TryParse
works more fast and more safe then just Parse
because doesn't throw an exception in case of error. TryParse
returns bool that indicates was parse successful or was not.
So both parsing methods should return true
and only after that - do the main check
bool male, female;
if ((Boolean.TryParse(staff.getValue("Male"), out male) &&
Boolean.TryParse(staff.getValue("Female"), out female)) &&
(male || female)) // or ^
{
// do stuff
}
or
bool male, female;
if (Boolean.TryParse(staff.getValue("Male"), out male) &&
Boolean.TryParse(staff.getValue("Female"), out female))
{
if(male) { }
else if (female) { } // or just else
}
else
{
// staff contains wrong data. Probably "yeap" instead of "true"
}
To indicate whether a gender is specified with a value of "true" rather than "false",
bool genderIsSpecified = staff.getValue("Male") | staff.getValue("Female");
.. will only determine whether it's one of those values, not which of those values the object staff
is.
So, just in case this question is literal and not an abstract example, ...
Male or Female .. everyone is one or the other. Perhaps in your question you meant to ask which of the two is the case? In that case,
bool defaultGenderIfNoGenderDocumented = true; // male
bool MaleIfTrue_FemaleIfFalse = !string.IsNullOrEmpty(staff.getValue("Male"))
? bool.Parse(staff.getValue("Male"))
: string.IsNullOrEmpty(staff.getValue("Female"))
? bool.Parse(staff.getValue("Female"))
? false
: defaultGenderIfNoGenderDocumented
: defaultGenderIfNoGenderDocumented;
Or simply,
// assume value is properly populated, ignore "Female" value
bool isMale = bool.Parse(staff.getValue("Male"));
This is a similar scenario but I am checking for three or more bool values.
Thread th = new Thread(() =>
{
while (true)
{
bool allReadComplete = true;
foreach (IDataProvider provider in lstDataProviders)
{
provider.StartReading();
if (provider.FinishedReading)
allReadComplete = allReadComplete && provider.FinishedReading;
else
allReadComplete = provider.FinishedReading;
}
// to induce some context switching
Thread.Sleep(0);
if (allReadComplete)
break;
}
Console.WriteLine("Thread Exiting");
});
th.IsBackground = true;
th.Start();
A little exception checking is needed anyway. The Boolean.Parse() method gets a string as argument and returns either true
or false
only if the argument, once stripped out of whitespace, is equal to "True" or "False" (note capitalization). In ANY other case the function returns an exception.
Supposing that the possible values of staff.getValue("Male")
and staff.getValue("Female")
are exactly those two, then the simple disjunction (||
) is sufficient. If any other return value is possible, including null
and the empty string, then you have to check for exceptions
bool isMale;
try {
isMale = Boolean.Parse(staff.getValue("Male"));
} catch(Exception e) {
isMale = Boolean.False;
}
try {
isFemale = Boolean.Parse(staff.getValue("Female"));
} catch(Exception e) {
isFemale = Boolean.False;
}
if (isMale || isFemale) // note double pipe ||
{
// do something if true
}
or compare manually
bool isMale = Boolean.TrueValue == staff.getValue("Male");
bool isFemale = Boolean.TrueValue == staff.getValue("Female");
if (isMale || isFemale) // note double pipe ||
{
// do something if true
}
精彩评论