Can't delete a compiled file -  "file in use"

Posted on 2008-10-23
Last Modified: 2012-05-05
I'm running the code below that compiles and runs a dll. It works great - except when the program loops back around it can't delete the existing dll because "file is in use"
Once the dll below is created and run, how can i released it so i can then delete it?

            If m_Code.Trim <> "" Then

                If m_Namespace.Trim <> "" Then

                    If m_ClassName.Trim <> "" Then



                            If File.Exists(m_AppPath & "\" & m_Namespace & ".dll") Then File.Delete(m_AppPath & "\" & m_Namespace & ".dll")

                            If File.Exists("c:\windows\system32\" & m_Namespace & ".dll") Then File.Delete("c:\windows\system32\" & m_Namespace & ".dll")


                        End Try


                        Dim VBP As New VBCodeProvider()

                        Dim CVB As System.CodeDom.Compiler.ICodeCompiler

                        CVB = VBP.CreateCompiler

                        Dim PM As New System.CodeDom.Compiler.CompilerParameters()

                        PM.GenerateInMemory = False

                        PM.OutputAssembly = m_Namespace & ".dll"

                        PM.MainClass = m_ClassName

                        PM.IncludeDebugInformation = True


                        'Add assemblies

                        Dim ASM As System.Reflection.Assembly

                        For Each ASM In AppDomain.CurrentDomain.GetAssemblies()



                        PM.ReferencedAssemblies.Add(m_AppPath & "\ActiveReports.dll")

                        PM.ReferencedAssemblies.Add(m_AppPath & "\ActiveReports.XlsExport.dll")

                        PM.ReferencedAssemblies.Add(m_AppPath & "\ActiveReports.PdfExport.dll")

                        PM.ReferencedAssemblies.Add(m_AppPath & "\ActiveReports.Viewer.dll")

                        PM.ReferencedAssemblies.Add(m_AppPath & "\")


                        'here we do the deed

                        Dim Results As System.CodeDom.Compiler.CompilerResults

                        Results = CVB.CompileAssemblyFromSource(PM, m_Code)


                        'this is just to list out all the errors if any

                        Dim Err As System.CodeDom.Compiler.CompilerError

                        For Each err In Results.Errors

                            m_Results &= "Number " & err.ErrorNumber & " Text " & err.ErrorText & " Line " & err.Line & VbCrLf



                        Dim RunObj As New Object()

                        Dim vArgs() As Object

                        RunObj = Results.CompiledAssembly.CreateInstance(m_Namespace & "." & m_ClassName, False, Reflection.BindingFlags.CreateInstance, Nothing, vArgs, Nothing, Nothing)

                        If RunObj Is Nothing Then

                            m_Results &= "Unable to run dll - failed." & VbCrLf

                        End If



                        m_Results &= "No class name found." & VbCrLf

                    End If


                    m_Results &= "No namespace found." & VbCrLf

                End If


                m_Results &= "No code found." & VbCrLf

            End If


            If Len(m_Results) = 0 Then m_Results = "OK"

        Catch err As Exception

            m_Results &= "ERROR: " & err.Message & " " & err.StackTrace & VbCrLf

        End Try

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Question by:LosBear
LVL 11

Accepted Solution

melmers earned 250 total points
ID: 22892996
You can only unload an assembly if it is in another appdomain.
So you must create an appdomain which loads the compiled assembly and when it should unload you must unload the whole appdomain.

Here is an MSDN Magazine Article about it.

Author Closing Comment

ID: 31509268

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