Integer.TryParse - a better way?

Ryan Smith picture Ryan Smith · Jan 7, 2009 · Viewed 74.5k times · Source

I find myself often needing to use Integer.TryParse to test if a value is an integer. However, when you use TryParse, you have to pass a reference variable to the function, so I find myself always needing to create a blank integer to pass in. Usually it looks something like:

Dim tempInt as Integer
If Integer.TryParse(myInt, tempInt) Then

I find this to be quite cumbersome considering that all I want is a simple True / False response. Is there a better way to approach this? Why isn't there an overloaded function where I can just pass the value I want to test and get a true / false response?

Answer

Tom Anderson picture Tom Anderson · Jan 7, 2009

No need to declare the integer.

If Integer.TryParse(intToCheck, 0) Then

or

If Integer.TryParse(intToCheck, Nothing) Then

If you have .Net 3.5 ability you can create an extension method for strings.

Public Module MyExtensions

    <System.Runtime.CompilerServices.Extension()> _
    Public Function IsInteger(ByVal value As String) As Boolean
        If String.IsNullOrEmpty(value) Then
            Return False
        Else
            Return Integer.TryParse(value, Nothing)
        End If
    End Function

End Module

And then call like:

If value.IsInteger() Then

Sorry, getting carried away I know, but also you can add this to the MyExtensions class above in .Net 3.5 and not worry unless you need validations.

<System.Runtime.CompilerServices.Extension()> _
Public Function ToInteger(ByVal value As String) As Integer
    If value.IsInteger() Then
        Return Integer.Parse(value)
    Else
        Return 0
    End If
End Function

Then simply use

value.ToInteger()

This will return 0 if it isn't a valid Integer.