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。

Convert.ToInt32

有19种重载或者19种不同的调用方式。2010年的版本可能会更多。

它将尝试从以下类型进行转换;

对象，Boolean, Char, SByte, Byte, Int16, UInt16, Int32, UInt32, Int64, UInt64，单个，双精度，十进制，字符串，日期

它还有很多其他的方法;一种方法与数字基础有关，两种方法涉及系统。IFormatProvider

另一方面，Parse只有4种重载或者4种调用方法的不同方式。

Integer.Parse( s As String)

Integer.Parse( s As String,  style As System.Globalization.NumberStyles )

Integer.Parse( s As String, provider As System.IFormatProvider )

Integer.Parse( s As String,  style As System.Globalization.NumberStyles, provider As System.IFormatProvider )

If you've got a string, and you expect it to always be an integer (say, if some web service is handing you an integer in string format), you'd use Int32.Parse(). If you're collecting input from a user, you'd generally use Int32.TryParse(), since it allows you more fine-grained control over the situation when the user enters invalid input. Convert.ToInt32() takes an object as its argument. (See Chris S's answer for how it works) Convert.ToInt32() also does not throw ArgumentNullException when its argument is null the way Int32.Parse() does. That also means that Convert.ToInt32() is probably a wee bit slower than Int32.Parse(), though in practice, unless you're doing a very large number of iterations in a loop, you'll never notice it.

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。

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。

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);
        }
    }