检查文件是否是有效的 SQLite 数据库

我需要检查文件（扩展名未知）是否是有效的 SQLite 数据库。

我的函数工作正常，但是当失败时，退出函数后文件仍然被锁定：

Public Function IsSqliteDB(ByVal uPath As String) As Boolean

    'Workaround for my problem: Make a copy and work on this because this function is going to lock the file unfortunately
    Dim sNewPath As String
    sNewPath = Settings.Locations.Folder_LocalAppData_Temp & "\temp_" & Replace(Now.ToString, ":", "_") & ".db"

    modIO.FileForceCopy(uPath, sNewPath)

    Dim bIsSQLiteDB As Boolean = False

    Dim c As New dhRichClient3.cConnection
    Dim r As dhRichClient3.cRecordset


    Try
        Dim b As Boolean = c.OpenDB(sNewPath) 'returns true although this is not an sqlite-db. Can't do anything about it
        R = c.OpenRecordset("SELECT * FROM sqlite_master")
        bIsSQLiteDB = True

    Catch ex As Exception
        r = Nothing
        c = Nothing
    Finally
        r = Nothing
        c = Nothing
    End Try

    modIO.DeleteFile(sNewPath)'this fails. File is locked

    Return bIsSQLiteDB

End Function

有人知道我可以在哪里确保文件不再被锁定吗？或者我真的必须使用该文件的副本吗，因为 COM 组件的行为并不真正已知（不幸的是闭源）？ 我确实可以使用备份，但该文件可能非常大（> 1 GB），因此如果可以避免的话，我想避免制作副本来处理。

dhRichClient 中没有“关闭”功能。我猜，一旦 cConnection 超出范围，就会在内部调用“关闭”。在函数末尾调用 GC.Collect() 没有帮助。

要确定一个文件是否是 SQLite 数据库，只需检查该文件的前 16 个字节数据库头 http://www.sqlite.org/fileformat2.html#database_header.

来自 tmighty 的评论：

Public Function IsSqliteDB(ByVal uPath As String) As Boolean
    Dim bytes(16) As Byte
    Using fs As New IO.FileStream(uPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite)
        fs.Read(bytes, 0, 16)
    End Using
    Dim text As String = System.Text.ASCIIEncoding.ASCII.GetString(bytes)
    Return text.Contains("SQLite format")
End Function