How To Change the Value in the app.config File

If you need to be able to change values in your application's app.config file, then it is surprisingly easy :)

In VB

Dim config As Configuration = ConfigurationManager.OpenExeConfiguration( _
    ConfigurationUserLevel.None)
config.ConnectionStrings.ConnectionStrings("MyDB") _
    .ConnectionString = "A_DB_CONNECTION_STRING"
config.AppSettings.Settings("MySetting").Value = "A_SETTING_VALUE"
config.Save(ConfigurationSaveMode.Modified)
ConfigurationManager.RefreshSection("connectionStrings")
ConfigurationManager.RefreshSection("appStrings")

In C#

Configuration config = ConfigurationManager.OpenExeConfiguration(
     ConfigurationUserLevel.None);
config.ConnectionStrings.ConnectionStrings["MyDB"]
    .ConnectionString = "A_DB_CONNECTION_STRING";
config.AppSettings.Settings["MySetting"].Value = "A_SETTING_VALUE";
config.Save(ConfigurationSaveMode.Modified);
ConfigurationManager.RefreshSection("connectionStrings");
ConfigurationManager.RefreshSection("appStrings");

In these examples, I am changing a connection string value and an app setting value. Once the config has been saved the modified section(s) need to be refreshed to ensure the new mods are loaded back into memory.

Remember that if your app is re-installed, then the modified app.config will be overwritten.

Method VBProject of _workbook Failed

I ran recently ran an old bit of Excel VBA in Excel 2010 which automatically adds the Microsoft Scripting Runtime to the workbook for me. Rather annoyingly, I was getting a Method VBProject of _workbook Failed error.

I solved this by going into the Options > Trust Center > Trust Centre Settings... Choosing Macro Settings and then checking the Trust access to the VBA project object model checkbox.

The code to add the reference in case that helps too ;)

Public Sub SomeMethod()

    AddReference "C:\WINDOWS\system32\scrrun.dll"

End Sub

Private Sub AddReference(sFile As String)
Dim i As Integer
Dim bFound As Boolean

    bFound = False
    For i = 1 To ActiveWorkbook.VBProject.References.Count
        If ActiveWorkbook.VBProject.References.Item(i).FullPath = sFile Then
            bFound = True
            Exit For
        End If
    Next i
    If Not bFound Then
        ActiveWorkbook.VBProject.References.AddFromFile sFile
    End If
End Sub