c# - 错误告诉我我还没有关闭连接，但不是吗？

Question

我一定是漏掉了什么。我正在尝试创建一个表，但我收到一条错误消息，告诉我连接仍处于打开状态。但是哪里？？？我重新阅读了代码，但找不到连接仍然打开的位置...

问题出在这里:objOleDbConnection.Open()

错误说:

You attempted to open a database that is already opened by user 'Admin' on machine 'machine'. Try again when the database is available.

private void sfdNewFile_FileOk(object sender, System.ComponentModel.CancelEventArgs e)
{
    // Creating a ADOX object needed to create
    // new MS Access file.
    ADOX.Catalog createMSFile = new ADOX.Catalog();
    // Creating an object for a table.
    Table nTable = new Table();

    // Creating an object allowing me connecting to the database.
    OleDbConnection objOleDbConnection = new OleDbConnection();
    objOleDbConnection.ConnectionString = "Provider=Microsoft.ACE.OLEDB.12.0;" +
            "Data Source=" + sfdNewFile.FileName + ";Persist Security Info=False;Mode=12";
    // Creating command object.
    OleDbCommand objOleDbCommand = new OleDbCommand();
    objOleDbCommand.Connection = objOleDbConnection;

    try
    {
        // Created a new MS Access 2007 file with specified path.
        createMSFile.Create("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" +
            sfdNewFile.FileName);

        objOleDbConnection.Open();
        objOleDbCommand.CommandText = "CREATE TABLE PersonalData (" +
            "[DataID] AUTOINCREMENT NOT NULL PRIMARY KEY ," +
            "[Type] VARCHAR(40) NOT NULL ," +
            "[URL] VARCHAR(40) NOT NULL ," +
            "[SoftwareName] VARCHAR(40) NOT NULL ," +
            "[SerialCode] VARCHAR(40) NOT NULL ," +
            "[UserName] VARCHAR(40) NOT NULL ," +
            "[Password] VARCHAR(40) NOT NULL";

        objOleDbCommand.ExecuteNonQuery();
    }
    catch (Exception ex)
    {
        // Displaying any errors that 
        // might have occured.
        MessageBox.Show("Error: " + ex.Message);
    }
    finally
    {
        // It is importnat to release COM object, in this very order
        // otherwise we eill end up with an error.
        System.Runtime.InteropServices.Marshal.FinalReleaseComObject(createMSFile);

        // Closing the connection to the database.
        objOleDbConnection.Close();
    }
}

Answer 1

ADOX 对象似乎也应该关闭它的连接。 查看以下来自 Microsoft 的示例: http://msdn.microsoft.com/en-us/library/windows/desktop/ms681562(v=vs.85).aspx

他们的 ADOX 对象名为 cat。 他们有以下几点:

cat.ActiveConnection = Nothing

这可能会转化为:

createMSFile.ActiveConnection = null

在您的代码中(可能在第一个 Finally block 中)。 我认为是 ADOX 对象造成了差异，在处理它之前，尝试将它的 ActiveConnection 设置为 null。