[DllImport("advapi32.dll", EntryPoint = "CredDeleteW", CharSet = CharSet.Unicode)]

    private static extern bool CredDelete(string target, CRED_TYPE type, int flags);

  Public Declare Unicode Function CredDelete Lib "advapi32.dll" Alias "CredDeleteW" ( ByVal TargetName As String, ByVal Type As Integer, ByVal Flags As Integer) As Boolean

The CredDelete 'type' method parameter (int) must be one of the constant CRED_TYPE_* values.

    CredDelete("YourTarget", CRED_TYPE.GENERIC, 0);

    [DllImport("advapi32.dll", EntryPoint = "CredDeleteW", CharSet = CharSet.Unicode)]

    static extern bool CredDelete(string target, int type, int flags);