Tuesday, 11 March 2014

Difference Between Int32.Parse(), Convert.ToInt32(), and Int32.TryParse()

Int32.Parse (string s) method converts the string representation of a number to its 32-bit signed integer equivalent. When is a null reference, it will throw ArgumentNullException. If is other than integer value, it will throw FormatException. When represents a number less than MinValue or greater than MaxValue, it will throw OverflowException. For example:
string s1 = "1234";
string s2 = "1234.65";
string s3 = null;
string s4 = "123456789123456789123456789123456789123456789";

int result;
bool success;

result = Int32.Parse(s1); //-- 1234
result = Int32.Parse(s2); //-- FormatException
result = Int32.Parse(s3); //-- ArgumentNullException
result = Int32.Parse(s4); //-- OverflowException

Convert.ToInt32(string s) method converts the specified string representation of 32-bit signed integer equivalent. This calls in turn Int32.Parse () method. When is a nullreference, it will return rather than throw ArgumentNullException. If is other thaninteger value, it will throw FormatException. When represents a number less thanMinValue or greater than MaxValue, it will throw OverflowException. For example:
result = Convert.ToInt32(s1); //-- 1234
result = Convert.ToInt32(s2); //-- FormatException
result = Convert.ToInt32(s3); //-- 0
result = Convert.ToInt32(s4); //-- OverflowException

Int32.TryParse(string, out int)
Int32.Parse(string, out int) method converts the specified string representation of 32-bit signed integer equivalent to out variable, and returns true if it is parsed successfully, false otherwise. This method is available in C# 2.0. When is a null reference, it will return 0 rather than throw ArgumentNullException. If is other than an integer value, the out variable will have rather than FormatException. When represents a number less than MinValue or greater than MaxValue, the out variable will have rather than OverflowException. For example:
success = Int32.TryParse(s1, out result); //-- success => true; result => 1234
 success = Int32.TryParse(s2, out result); //-- success => false; result => 0
 success = Int32.TryParse(s3, out result); //-- success => false; result => 0
 success = Int32.TryParse(s4, out result); //-- success => false; result => 0

Convert.ToInt32 is better than Int32.Parse since it returns rather than an exception. But again, according to the requirement, this can be used. TryParse will be the best since it always handles exceptions by itself.

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