Convert & parse

Question

Convert .ToInt32() and Int32 .Parse()
Even though both looks different but do similar operations. I wish to know whether it is used for different purposes.

Answer

Thank you very much for your explanation guys.

Senthilkumar · Answer

The int32.parse and Convert.ToInt32() both is used to the type conversion of integer type.
But the Convert.ToInt32() is a type safe conversion. why because you can't predict the value at the run time. in case value is null then it can be assumed as zero rather than throw the exception at the certain cases.
but the int32.parse do not have the control to implicitly convert null into zero value. instead of that it throws exception  when you try to convert the null into integer value.
At the same time the Convert.ToInt32() handle implicitly when the type value is null.
Always recommended to use the Convert.Toint32() function for integer type conversion.
Thanks,
Senthil.

Vulpes · Answer

Also, the Int32.TryParse(string, out int) method is a good way of avoiding any kind of invalid input including a null string.
int i;   bool isValid = Int32.TryParse("xyz", out i);
This returns false because "xyz" can't be parsed to an integer and places 0 in the output parameter i.
In contrast:
int i;   bool isValid = Int32.TryParse("123", out i);
returns true and places 123 in the output parameter i.
This method is effectively a shortcut for placing Int32.Parse in a try/catch statement and catching any format, null reference or overflow exceptions.

Datta Kharad · Answer

Ex:-
string str = "230";
int iNum = Convert.ToInt32(str);
int iNum2 = int.Parse(str);
//Result:-  iNum =230
iNum2 =230
// It will give same Result but in case string is null then int.Parse method cant handle null value.
string str = null;
int iNum = Convert.ToInt32(str);
int iNum2 = int.Parse(str);
//Result:- iNum=0;
iNum2= (it will throw error "Value cannot be null.")
The two give identical results, except where the string is null. Convert.ToInt32(null) returns zero, whereas Int32.Parse(null) throws an ArgumentNullException.

Satyapriya Nayak · Answer

Hi Maha,
Int32.Parse (string s) method converts the string representation of a number to its 32-bit signed integer equivalent. When s is a null reference, it will throw ArgumentNullException. If s is other than integer value, it will throw FormatException. When s represents a number less than MinValue or greater than MaxValue, it will throw 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 s is a null reference, it will return 0 rather than throw ArgumentNullException. If s is other than integer value, it will throw FormatException. When s represents a number less than MinValue or greater than MaxValue, it will throw OverflowException.
Refer
http://www.codeproject.com/KB/cs/AgileWare_Convert_Int32.aspx
Thanks

Dharmesh Sharma · Answer

hello, Maha
@ Convert .ToInt32() when you use if the object is null throw exception ,
in case of  Int32 .Parse() its show another excetion you can check it
thanks