How do I store and retrieve an Enum in My.Settings

Question

I am trying to store and retrieve a ContentAlignment Enum in My.Settings via a combobox. I have setup this Type in Project Settings. I'm populating a combobox on a settings form with the relevant Enum values:

With ControlAnchorCB
        .Items.AddRange([Enum].GetNames(GetType(ContentAlignment)))
End With

I then try to set the combobox to the one in My.Settings:

ControlAnchorCB.SelectedItem = My.Settings.ConnectorControlAnchor

but no value shows. I also try to save the selected combobox value back to My.Settings with:

My.Settings.ConnectorControlAnchor = ControlAnchorCB.SelectedItem

However, this results in an exception: "System.InvalidCastException: 'Conversion from string "MiddleCenter" to type 'Integer' is not valid.'"

Update: Another limitation is that I'm coding in Framework 3.5 (has to be this version) and vb.net. Thus, Enum.TryParse is not available.

How can I achieve this?

When you save an enum, cast it to int or call `.ToString()` on the enum. When you restore it from the settings, get the string or int value, and use `Enum.TryParse` or cast the int back to enum. Set a breakpoint to see if it worked... — Charles, Dec 27 '21 at 20:03
Thanks both. I forgot to mention that I'm having to do this in Framework 3.5 and in vb.net. Thus, Enum.TryParse is not available. :( — stigzler, Dec 28 '21 at 13:46

score 0 · Answer 1 · answered Dec 28 '21 at 14:14

After much faffing about solved it:

    ' My.Settings.ConnectorControlAnchor Type is set to ContentAlignment in Project Settings.   
    
    Public Function TryParse(Of TEnum As {Structure, IConvertible})(ByVal value As String, <Out> ByRef result As TEnum) As Boolean
        Dim retValue = If(value Is Nothing, False, [Enum].IsDefined(GetType(TEnum), value))
        result = If(retValue, CType([Enum].Parse(GetType(TEnum), value), TEnum), Nothing)
        Return retValue
    End Function
    
    ' Populate ComboBox
    With ControlAnchorCB
        .Items.AddRange([Enum].GetNames(GetType(ContentAlignment)))
    End With
        
    ' Set combobox to value in My.Settings
    Dim ca As New ContentAlignment
    ControlAnchorCB.SelectedIndex = ControlAnchorCB.FindStringExact(My.Settings.ConnectorControlAnchor.ToString)

    ' To save value of combobox to My.Settings
    Dim ca As New ContentAlignment
    If TryParse(Of ContentAlignment)(ControlAnchorCB.SelectedItem, ca) Then My.Settings.ConnectorControlAnchor = ca

How do I store and retrieve an Enum in My.Settings

1 Answers1