Question

I have a VB.NET project in Visual Studio 2008 that I created a specialized addin for. The addin prompts the user to select a database table, takes a template form class’s files, copies them to another directory within the project, and renames the form class within the copied files. It then opens the new form and adds controls to it based on the fields in the database table.

The copying of the template form causes the background compiler to give ‘duplicate member’ errors, such as “Private Sub InitializeComponents(…) has multiple definitions with identical signatures,” even though I renamed the files of the new form and the class name within them. Sometimes these errors go away before the new form is opened, but when they stick around the new form doesn’t open correctly, and it throws an error instead.

I implemented some code to wait until there are zero errors in the error list before trying to open the new form. This has helped sometimes, but for some reason sometimes the errors don’t go away at all until the addin is closed.

I was hoping someone could give tips on how to copy the template form and rename the copy without the background compiler ever noticing duplicate members. If that’s not possible, then perhaps someone has an alternative?

Here is my code that copies and renames the template form:

Private Sub CreateDataForm(ByVal tableName As String, ByVal displayName As String) ', ByVal subDataForms As IList(Of Object))
    Try
        Dim dataFormClassName As String = "frm" & MakeValidName(displayName)
        Dim dataFormFileName As String = dataFormClassName & cVBSuffix
        Dim templateFileName As String = DataFormTemplate.Name
        Dim templateClassName As String = Replace(templateFileName, cVBSuffix, String.Empty)

        'copy form template to data forms folder
        'copy files associated with main projectitem
        Dim newPItem As ProjectItem = Nothing

        For i As Integer = 1 To DataFormTemplate.FileCount
            newPItem = DataFormsFolder.ProjectItems.AddFromFileCopy(DataFormTemplate.FileNames(CShort(i)))
        Next

        'copy files associated with sub projectitems
        For Each item As ProjectItem In DataFormTemplate.ProjectItems
            For i As Integer = 1 To item.FileCount
                DataFormsFolder.ProjectItems.AddFromFileCopy(item.FileNames(CShort(i)))
            Next
        Next

        newPItem.Name = dataFormFileName

        newPItem.ContainingProject.Save()

        'fix class name for dataform template
        FixDataFormClassName(DataFormTemplate, dataFormClassName, templateClassName)

        newPItem.ContainingProject.Save()

        Application.DoEvents()

        'get table metadata
        Dim lGetColumnInfo As DataColumnCollection = GetColumnInfo(tableName)


        'add field controls
        ConvertColumnInfoToFormControls(newPItem, lGetColumnInfo, tableName, displayName)

    Catch ex As Exception
        DisplayExceptionMessage(ex)
    End Try
End Sub

Private Shared Sub FixDataFormClassName(ByVal pItem As ProjectItem, ByVal dataFormClassName As String, ByVal templateClassName As String)
    If pItem.Document IsNot Nothing Then
        pItem.Document.Close(vsSaveChanges.vsSaveChangesPrompt)
    End If
    For i As Integer = 1 To pItem.FileCount
        Dim dftFile As New IO.FileInfo(pItem.FileNames(CShort(i)))
        Dim tr As IO.TextReader = dftFile.OpenText() 'IO.FileMode.Open, IO.FileAccess.ReadWrite, IO.FileShare.None)
        Dim sb As New Text.StringBuilder
        Dim newData As String = tr.ReadToEnd().Replace(dataFormClassName, templateClassName)
        tr.Close()
        Dim sw As New IO.StreamWriter(dftFile.FullName)
        sw.Write(newData)
        sw.Close()
    Next

    If pItem.FileCodeModel IsNot Nothing Then CType(pItem.FileCodeModel, FileCodeModel2).Synchronize()

    For Each item As ProjectItem In pItem.ProjectItems
        FixDataFormClassName(item, dataFormClassName, templateClassName)
    Next
End Sub

Answer 1

After all my attempts at correcting this via Visual Studio’s Extensibility API, I gave up with that approach and now do all the dirty work behind the scenes. I take the template form’s files, copy them to the new directory, and change their file names and contents all behind the scenes via FileInfo objects and whatnot before I add the new files to the project. This way, VS is never in a state where there are ‘duplicate member’ errors.

If anyone ever wants to see the code, holler and I’ll post it up.