Difference between Convert.ToDecimal(string) & Decimal.Parse(string)

There is one important difference to keep in mind:

Convert.ToDecimal will return 0 if it is given a null string.

decimal.Parse will throw an ArgumentNullException if the string you want to parse is null.

From bytes.com:

The Convert class is designed to convert a wide range of Types, so you can convert more types to Decimal than you can with Decimal.Parse, which can only deal with String. On the other hand Decimal.Parse allows you to specify a NumberStyle.

Decimal and decimal are aliases and are equal.

For Convert.ToDecimal(string), Decimal.Parse is called internally.

Morten Wennevik [C# MVP]

Since Decimal.Parse is called internally by Convert.ToDecimal, if you have extreme performance requirements you might want to stick to Decimal.Parse, it will save a stack frame.

One factor that you might not have thought of is the Decimal.TryParse method. Both Convert.ToDecimal and Parse throw exceptions if they cannot convert the string to the proper decimal format. The TryParse method gives you a nice pattern for input validation.

decimal result;
if (decimal.TryParse("5.0", out result))
   ; // you have a valid decimal to do as you please, no exception.
else
   ; // uh-oh.  error message time!

This pattern is very incredibly awesome for error-checking user input.

One common suggestion related to original topic - please use TryParse() as soon as you not really sure that input string parameter WILL be correct number format representation.

Knowing that Convert.ToDecimal is the way to go in most cases because it handles NULL, it, however, does not handle empty string very well. So, the following function might help:

'object should be a string or a number
Function ConvertStringToDecimal(ByVal ValueToConvertToDecimal As Object) As Decimal
    If String.IsNullOrEmpty(ValueToConvertToDecimal.ToString) = False Then
        Return Convert.ToDecimal(ValueToConvertToDecimal)
    Else
        Return Convert.ToDecimal(0)
    End If
End Function