Setting the value of a constant or variable at build time

Question

I would like to have a Constant or field defined in my application startup code that reflect the date that the application was actually built. Something like for example:

 Private Shared ApplicationBuiltOn As Date = <and here is where I would like to set the build date>`

Can this be done using build events so that it is always set and I don't actively have to remember to do it prior to actively building a release version.

If it is possible how does one do it? I've read through the msdn documentation on build events but nothing seems to cover what I'd like to try and do.

Answer 1

You could try this (tested it and worked for me)

Public NotInheritable Class ApplicationInformation
    Private Sub New()
    End Sub
    ''' <summary>
    ''' Gets the executing assembly.
    ''' </summary>
    ''' <value>The executing assembly.</value>
    Public Shared ReadOnly Property ExecutingAssembly() As System.Reflection.Assembly
        Get
            Return If(m_executingAssembly, (InlineAssignHelper(m_executingAssembly, System.Reflection.Assembly.GetExecutingAssembly())))
        End Get
    End Property
    Private Shared m_executingAssembly As System.Reflection.Assembly

    ''' <summary>
    ''' Gets the executing assembly version.
    ''' </summary>
    ''' <value>The executing assembly version.</value>
    Public Shared ReadOnly Property ExecutingAssemblyVersion() As System.Version
        Get
            Return If(m_executingAssemblyVersion, (InlineAssignHelper(m_executingAssemblyVersion, ExecutingAssembly.GetName().Version)))
        End Get
    End Property
    Private Shared m_executingAssemblyVersion As System.Version

    ''' <summary>
    ''' Gets the compile date of the currently executing assembly.
    ''' </summary>
    ''' <value>The compile date.</value>
    Public Shared ReadOnly Property CompileDate() As System.DateTime
        Get
            If Not m_compileDate.HasValue Then
                m_compileDate = RetrieveLinkerTimestamp(ExecutingAssembly.Location)
            End If
            Return If(m_compileDate, New System.DateTime())
        End Get
    End Property
    Private Shared m_compileDate As System.Nullable(Of System.DateTime)

    ''' <summary>
    ''' Retrieves the linker timestamp.
    ''' </summary>
    ''' <param name="filePath">The file path.</param>
    ''' <returns></returns>
    ''' <remarks>http://www.codinghorror.com/blog/2005/04/determining-build-date-the-hard-way.html</remarks>
    Private Shared Function RetrieveLinkerTimestamp(filePath As String) As System.DateTime
        Const  peHeaderOffset As Integer = 60
        Const  linkerTimestampOffset As Integer = 8
        Dim b = New Byte(2047) {}
        Dim s As System.IO.FileStream = Nothing
        Try
            s = New System.IO.FileStream(filePath, System.IO.FileMode.Open, System.IO.FileAccess.Read)
            s.Read(b, 0, 2048)
        Finally
            If s IsNot Nothing Then
                s.Close()
            End If
        End Try
        Dim dt = New System.DateTime(1970, 1, 1, 0, 0, 0).AddSeconds(System.BitConverter.ToInt32(b, System.BitConverter.ToInt32(b, peHeaderOffset) + linkerTimestampOffset))
        Return dt.AddHours(System.TimeZone.CurrentTimeZone.GetUtcOffset(dt).Hours)
    End Function
    Private Shared Function InlineAssignHelper(Of T)(ByRef target As T, value As T) As T
        target = value
        Return value
    End Function
End Class

And use it like this:

Messagebox.Show("This application was built on: " & ApplicationInformation.CompileDate.ToString())

NOTE: Grabbed together from https://stackoverflow.com/a/3634544/4237809 and http://blog.codinghorror.com/determining-build-date-the-hard-way/