区别在于:

Int32.Parse()和Int32.TryParse()只能转换字符串。Convert.ToInt32()可以接受任何实现IConvertible的类。如果传递给它一个字符串，那么它们是等效的，除了类型比较等额外开销。如果要转换字符串，那么TryParse()可能是更好的选择。

这取决于参数类型。例如，我今天刚刚发现，它将使用ASCII值直接将char转换为int。这不是我想要的功能…

我警告过你!

public static int ToInt32(char value)
{
    return (int)value;
} 

Convert.ToInt32('1'); // Returns 49
int.Parse('1'); // Returns 1

Parse()方法提供了不能用于Convert()的数字样式。例如:

int i;
bool b = int.TryParse( "123-",
           System.Globalization.NumberStyles.AllowTrailingSign,
           System.Globalization.CultureInfo.InvariantCulture,
           out i);

会解析带尾符号的数字，以便I == -123 尾随符号在ERP系统中很流行。

TryParse更快…

The first of these functions, Parse, is one that should be familiar to any .Net developer. This function will take a string and attempt to extract an integer out of it and then return the integer. If it runs into something that it can’t parse then it throws a FormatException or if the number is too large an OverflowException. Also, it can throw an ArgumentException if you pass it a null value. TryParse is a new addition to the new .Net 2.0 framework that addresses some issues with the original Parse function. The main difference is that exception handling is very slow, so if TryParse is unable to parse the string it does not throw an exception like Parse does. Instead, it returns a Boolean indicating if it was able to successfully parse a number. So you have to pass into TryParse both the string to be parsed and an Int32 out parameter to fill in. We will use the profiler to examine the speed difference between TryParse and Parse in both cases where the string can be correctly parsed and in cases where the string cannot be correctly parsed. The Convert class contains a series of functions to convert one base class into another. I believe that Convert.ToInt32(string) just checks for a null string (if the string is null it returns zero unlike the Parse) then just calls Int32.Parse(string). I’ll use the profiler to confirm this and to see if using Convert as opposed to Parse has any real effect on performance.

带有示例的源代码

希望这能有所帮助。

int。Parse (string s)

RANGE >中的整数返回整数值 空值> argementnullexception 格式不是> FormatException 值不在RANGE > OverflowException

转换。ToInt32(字符串)

RANGE >中的整数返回整数值 空值>返回“0” 格式不是> FormatException 值不在RANGE > OverflowException

bool isParsed = int。TryParse（string s，out res）

RANGE中的整数>返回整数值，isParsed = true 空值>返回“0”，isParsed = false 不是格式>返回"0"，isParsed = false 值不在RANGE >返回"0"，isParsed = false

试试.....下面的代码

class Program
{
    static void Main(string[] args)
    {
        string strInt = "24532";
        string strNull = null;
        string strWrongFrmt = "5.87";
        string strAboveRange = "98765432123456";
        int res;
        try
        {
            // int.Parse() - TEST
            res = int.Parse(strInt); // res = 24532
            res = int.Parse(strNull); // System.ArgumentNullException
            res = int.Parse(strWrongFrmt); // System.FormatException
            res = int.Parse(strAboveRange); // System.OverflowException

            // Convert.ToInt32(string s) - TEST
            res = Convert.ToInt32(strInt); // res = 24532
            res = Convert.ToInt32(strNull); // res = 0
            res = Convert.ToInt32(strWrongFrmt); // System.FormatException
            res = Convert.ToInt32(strAboveRange); //System.OverflowException

            // int.TryParse(string s, out res) - Test
            bool isParsed;
            isParsed = int.TryParse(strInt, out res); // isParsed = true, res = 24532
            isParsed = int.TryParse(strNull, out res); // isParsed = false, res = 0
            isParsed = int.TryParse(strWrongFrmt, out res); // isParsed = false, res = 0
            isParsed = int.TryParse(strAboveRange, out res); // isParsed = false, res = 0 
        }
        catch(Exception e)
        {
            Console.WriteLine("Check this.\n" + e.Message);
        }
    }

请看反射镜:

int.Parse("32"):

public static int Parse(string s)
{
    return System.Number.ParseInt32(s, NumberStyles.Integer, NumberFormatInfo.CurrentInfo);
}

这是一个调用:

internal static unsafe int ParseInt32(string s, NumberStyles style, NumberFormatInfo info)
{
    byte* stackBuffer = stackalloc byte[1 * 0x72];
    NumberBuffer number = new NumberBuffer(stackBuffer);
    int num = 0;
    StringToNumber(s, style, ref number, info, false);
    if ((style & NumberStyles.AllowHexSpecifier) != NumberStyles.None)
    {
        if (!HexNumberToInt32(ref number, ref num))
        {
            throw new OverflowException(Environment.GetResourceString("Overflow_Int32"));
        }
        return num;
    }
    if (!NumberToInt32(ref number, ref num))
    {
        throw new OverflowException(Environment.GetResourceString("Overflow_Int32"));
    }
    return num;
}

Convert.ToInt32("32"):

public static int ToInt32(string value)
{
    if (value == null)
    {
        return 0;
    }
    return int.Parse(value, CultureInfo.CurrentCulture);
}

正如第一个(Dave M的)评论所说。