I mentioned in a comment a while ago < em> "Both do the same, except that they throw different exceptions based on the value they 'parse'."

Having said that (source) , you have the following:

string convertToInt = "12";
string nullString = null;
string maxValue = "32222222222222222222222222222222222";
string formatException = "12.32";

int parseResult;

// Convertirá correctamente.
parseResult = int.Parse(convertToInt);

// Arrojará NullException.
parseResult = int.Parse(nullString); 

// Arrojará OverflowException .
parseResult = int.Parse(maxValue);

// Arrojará FormatException.
parseResult = int.Parse(formatException);


// Lo mismo, utilizando Convert.ToInt32

// Funcionará perfecto.
parseResult = Convert.ToInt32(convertToInt);

// Retornará Cero si el string es null.
parseResult = Convert.ToInt32(nullString);

// Arrojará OverflowException
parseResult = Convert.ToInt32(maxValue);

// Arrojará FormatException
parseResult = Convert.ToInt32(formatException);

You can try a Fiddle here . :)

EDIT:

Convert.ToInt32() has different overloads that allow you to cast virtually anything to int , however to int.Parse() you can only pass string , throwing the respective exceptions mentioned above in case case, mentioning that int.Parse() has several overloads to specify the format of the number.

EDIT 2:

In the end, very very deep, both implementations call a method called Number.Parse that is internal to the .NET Framework, see the source code of both functions below 1 :

// Int32.Parse(String s) Implementación.
[Pure]
public static int Parse(String s) {
    return Number.ParseInt32(s, NumberStyles.Integer, NumberFormatInfo.CurrentInfo);
}

// Convert.ToInt32(String value) implementación.
public static int ToInt32(String value) {
    if (value == null)
        return 0;
    return Int32.Parse(value, CultureInfo.CurrentCulture);
}

What you say, at the call level, yes, Int32.Parse(string) may be faster, since you save an internal call, not as Convert.ToInt32(object) , which first evaluates the object to be converted and then calls the% method Parse() .

1 : Source code of both implementations thanks to Reference Source See: Convert.ToInt32(string) and Int32.Parse(string) .

Both forms are valid, one the difference that I see is that the Convert.ToInt32 () allows you to assign several types of data as parameter

Convert.ToInt32

while Int32.Parse () can only pass a string

Int32.Parse (String)

both are valid

If you have the

Int32.TryParse ()

in case you want to validate the converison without receiving an Exception