.NET 可以在没有 If 的情况下将“Yes”和“No”转换为布尔值吗？
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Can .NET convert "Yes" & "No" to boolean without If?
提问by hawbsl
You would think there would be a way using DirectCast, TryCast, CType etc but all of them seem to choke on it e.g.:
你会认为有一种方法可以使用 DirectCast、TryCast、CType 等，但它们似乎都被它窒息了，例如：
CType("Yes", Boolean)
You get:
你得到：
System.InvalidCastException - Conversion from string "Yes" to type 'Boolean' is not valid.
System.InvalidCastException - 从字符串“Yes”到类型“Boolean”的转换无效。
回答by slugster
If you think about it, "yes" cannot be converted to bool because it is a language and context specific string.
如果您考虑一下，“yes”不能转换为 bool，因为它是特定于语言和上下文的字符串。
"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.
“是的”不是真实的同义词（尤其是当你的妻子这么说时......！）。对于这样的事情，你需要自己转换它；“是”的意思是“真的”，“mmmm yeeessss”的意思是“一半是真的，一半是假的，也许”等等。
回答by Rubys
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)
使用这种方式，您可以定义从您喜欢的任何字符串到您需要的布尔值的转换。1是真的，0是假的，很明显。
优点：易于修改。您可以非常轻松地添加或删除新别名。
缺点：可能比简单的 if 花费的时间更长。（但如果你有多个别名，它会变得毛茸茸的）
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
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
回答by thelost
No, but you could do like:
不，但你可以这样做：
bool yes = "Yes".equals(yourString);
bool yes = "Yes".equals(yourString);
回答by sshow
private static bool GetBool(string condition)
{
return condition.ToLower() == "yes";
}
GetBool("Yes"); // true
GetBool("No"); // false
Or another approach using extension methods
或使用扩展方法的另一种方法
public static bool ToBoolean(this string str)
{
return str.ToLower() == "yes";
}
bool answer = "Yes".ToBoolean(); // true
bool answer = "AnythingOtherThanYes".ToBoolean(); // false
回答by Regent
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 YesNoBooleanConverterderived from BooleanConverterand decorating my property with <TypeConverter(GetType(YesNoBooleanConverter))> _...
有点偏离主题，但我需要一次让我的一个类在属性网格中显示“是/否”而不是“真/假”，所以我实现了YesNoBooleanConverter派生自BooleanConverter和装饰我的属性<TypeConverter(GetType(YesNoBooleanConverter))> _......
回答by Mubashar
You Can't. But you should use it as
你不能。但你应该把它用作
bool result = yourstring.ToLower() == "yes";
回答by ScottJamesSDF
C# 6+ version:
C# 6+ 版本：
public static bool StringToBool(string value) =>
value.Equals("yes", StringComparison.CurrentCultureIgnoreCase) ||
value.Equals(bool.TrueString, StringComparison.CurrentCultureIgnoreCase) ||
value.Equals("1");`
回答by STLDev
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.
我喜欢@thelost 发布的答案，但我正在从 ADO.Net DataTable 读取值，并且 DataTable 中字符串的大小写可能会有所不同。
The value I need to get as a boolean is in a DataTable named childAccountsin a column named Trades.
我需要作为布尔值获取的值位于childAccounts名为Trades.
I implemented a solution like this:
我实现了这样的解决方案：
bool tradeFlag = childAccounts["Trade"].ToString().Equals("yes", StringComparison.InvariantCultureIgnoreCase);
回答by dburtsev
private bool StrToBool(string value)
{ // could be yes/no, Yes/No, true/false, True/False, 1/0
bool b = false;
if (value.Equals("yes", StringComparison.CurrentCultureIgnoreCase) || value.Equals(Boolean.TrueString, StringComparison.CurrentCultureIgnoreCase) || value.Equals("1"))
{
b = true;
}
else if (value.Equals("no", StringComparison.CurrentCultureIgnoreCase) || value.Equals(Boolean.FalseString, StringComparison.CurrentCultureIgnoreCase) || value.Equals("0"))
{
b = false;
}
else
{ // we should't be here
b = false;
}
return b;
}
回答by FirebirdUSA
Here is a simple way to get this done.
这是完成此操作的简单方法。
rv.Complete = If(reader("Complete") = "Yes", True, False)
