如何將字符串轉換為布爾值

Question

我有一個可以是“0”或“1”的string ，並且保證它不會是其他任何東西。

所以問題是：將其轉換為bool的最佳、最簡單和最優雅的方法是什么？

Answer 1

確實很簡單：

bool b = str == "1";

Answer 2

忽略這個問題的特定需求，雖然將字符串轉換為 bool 從來都不是一個好主意，但一種方法是在 Convert 類上使用ToBoolean()方法：

bool val = Convert.ToBoolean("true");

或者一個擴展方法來做你正在做的任何奇怪的映射：

public static class StringExtensions
{
    public static bool ToBoolean(this string value)
    {
        switch (value.ToLower())
        {
            case  "true":
                return true;
            case "t":
                return true;
            case "1":
                return true;
            case "0":
                return false;
            case "false":
                return false;
            case "f":
                return false;
            default:
                throw new InvalidCastException("You can't cast that value to a bool!");
        }
    }
}

Answer 3

我知道這不能回答你的問題，只是為了幫助其他人。 如果您嘗試將“true”或“false”字符串轉換為布爾值：

嘗試 Boolean.Parse

bool val = Boolean.Parse("true"); ==> true
bool val = Boolean.Parse("True"); ==> true
bool val = Boolean.Parse("TRUE"); ==> true
bool val = Boolean.Parse("False"); ==> false
bool val = Boolean.Parse("1"); ==> Exception!
bool val = Boolean.Parse("diffstring"); ==> Exception!

Answer 4

bool b = str.Equals("1")? true : false;

或者甚至更好，如以下評論中所建議：

bool b = str.Equals("1");

Answer 5

我做了一些更可擴展的東西，捎帶在 Mohammad Sepahvand 的概念上：

    public static bool ToBoolean(this string s)
    {
        string[] trueStrings = { "1", "y" , "yes" , "true" };
        string[] falseStrings = { "0", "n", "no", "false" };


        if (trueStrings.Contains(s, StringComparer.OrdinalIgnoreCase))
            return true;
        if (falseStrings.Contains(s, StringComparer.OrdinalIgnoreCase))
            return false;

        throw new InvalidCastException("only the following are supported for converting strings to boolean: " 
            + string.Join(",", trueStrings)
            + " and "
            + string.Join(",", falseStrings));
    }

Answer 6

我使用以下代碼將字符串轉換為布爾值。

Convert.ToBoolean(Convert.ToInt32(myString));

Answer 7

這是我嘗試最寬容的字符串到布爾轉換仍然有用，基本上只關閉第一個字符。

public static class StringHelpers
{
    /// <summary>
    /// Convert string to boolean, in a forgiving way.
    /// </summary>
    /// <param name="stringVal">String that should either be "True", "False", "Yes", "No", "T", "F", "Y", "N", "1", "0"</param>
    /// <returns>If the trimmed string is any of the legal values that can be construed as "true", it returns true; False otherwise;</returns>
    public static bool ToBoolFuzzy(this string stringVal)
    {
        string normalizedString = (stringVal?.Trim() ?? "false").ToLowerInvariant();
        bool result = (normalizedString.StartsWith("y") 
            || normalizedString.StartsWith("t")
            || normalizedString.StartsWith("1"));
        return result;
    }
}

Answer 8

    private static readonly ICollection<string> PositiveList = new Collection<string> { "Y", "Yes", "T", "True", "1", "OK" };

public static bool ToBoolean(this string input)
{
                return input != null && PositiveList.Any(λ => λ.Equals(input, StringComparison.OrdinalIgnoreCase));
}

Answer 9

我用這個：

public static bool ToBoolean(this string input)
        {
            //Account for a string that does not need to be processed
            if (string.IsNullOrEmpty(input))
                return false;

            return (input.Trim().ToLower() == "true") || (input.Trim() == "1");
        }

Answer 10

我喜歡擴展方法，這是我使用的方法...

static class StringHelpers
{
    public static bool ToBoolean(this String input, out bool output)
    {
        //Set the default return value
        output = false;

        //Account for a string that does not need to be processed
        if (input == null || input.Length < 1)
            return false;

        if ((input.Trim().ToLower() == "true") || (input.Trim() == "1"))
            output = true;
        else if ((input.Trim().ToLower() == "false") || (input.Trim() == "0"))
            output = false;
        else
            return false;

        //Return success
        return true;
    }
}

然后使用它只是做一些像......

bool b;
bool myValue;
data = "1";
if (!data.ToBoolean(out b))
  throw new InvalidCastException("Could not cast to bool value from data '" + data + "'.");
else
  myValue = b;  //myValue is True

Answer 11

string sample = "";

bool myBool = Convert.ToBoolean(sample);

Answer 12

如果你想測試一個字符串是否是一個沒有任何拋出異常的有效布爾值，你可以試試這個：

    string stringToBool1 = "true";
    string stringToBool2 = "1";
    bool value1;
    if(bool.TryParse(stringToBool1, out value1))
    {
        MessageBox.Show(stringToBool1 + " is Boolean");
    }
    else
    {
        MessageBox.Show(stringToBool1 + " is not Boolean");
    }

輸出is Boolean ，而 stringToBool2 的輸出是：'不是布爾值'