Question

我的Access（2003）数据库中有一个备忘录字段，用于存储Outlook中文件夹的EntryID（大约750个字符）。我正在尝试取回 string 以使用以下代码将一些邮件移动到该文件夹ID：

Dim myNameSpace As Outlook.NameSpace
Dim StoreID As String
Dim target as String 'This is the long EntryID string
Dim objMail as mailitem 'some mail

Set myNameSpace = Application.GetNamespace("MAPI")
StoreID = Application.GetNamespace("MAPI").folders("LiveLink").StoreID
Set dossier = myNameSpace.GetFolderFromID(target, StoreID)
objMail.Move dossier

在这种情况下，target var只有前252个字符而不是748个字符。有趣的是，如果没有其他文件夹具有相同的~255个第一个字符，Outlook仍将找到正确的文件夹。但在某些情况下，它会崩溃，因为它不止一个。我正在使用 Recordset 从数据库中获取备忘录。这是我的SQL：

SELECT EntryID FROM Folder

我终于找到了一些关于这种行为的信息：http://allenbrowne.com/ser-63.html。但是，我没有在我的查询中使用任何联合或任何特殊内容，因为你可以看到......

为什么它仍然被截断？

数据库中的原始备忘录/字符串：

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

SQL查询后截断的memo / object / field / string：

00000000CE5B922DF5D7654C993FFDB4FF79A7A00100000057010000307E7E2D317E305C307E4C6976656C696E6B204851457E307E2D315C307E4C6976656C696E6B204851457E2D357E305C307E4C6976656C696E6B204851457E313233373235387E2D355C307E4C6976656C696E6B204851457E3130323336333431

Answer 1

如您的链接所示，这应该有效

Set rs = CurrentDb.Execute("SELECT Mid(EntryID,  1,250)  AS part1, " & _
       " Mid(EntryID,251,250)  AS part2," & _
       " Mid(EntryID,501,250)  AS part3," & _
       " Mid(EntryID,751,250)  AS part4," & _
       " Mid(EntryID,1001,250) AS part5 " & _
                          " FROM Folder;")
target = rs("part1") & rs("part2") & rs("part3") & rs("part4") & rs("part5")

Answer 2

我已经实现了这个c＃代码：

  private string GetMemoField(string TableName, string FieldName, string IdentityFieldName, string IdentityFieldValue, OleDbConnection conn)
    {
        string ret = "";

        OleDbCommand cmd1 = new OleDbCommand("SELECT " + FieldName + " FROM “ + TableName + “ WHERE " + IdentityFieldName + "=" + IdentityFieldValue, conn);

                var reader = cmd1.ExecuteReader(System.Data.CommandBehavior.SequentialAccess);  // Create the DataReader that will get the memo field one buffer at a time

        if (reader.Read())
        {
            long numberOfChars = reader.GetChars(/*Field pos*/ 0, 0, null, 0, 0);   // Total number of memo field's chars

            if (numberOfChars > 0)
            {
                int bufferSize = 1024;
                char[] totalBuffer = new char[64*bufferSize];    // Array to hold memo field content

                long dataIndex = 0;

                do
                {

                    char[] buffer = new char[bufferSize];   // Buffer to hold single read
                    long numberOfCharsReaded = reader.GetChars(0, dataIndex, buffer, 0, bufferSize);

                    if (numberOfCharsReaded == 0)
                    {
                        ret = new string(totalBuffer,0, (int)numberOfChars);
                        break;
                    }

                    Array.Copy(buffer, 0, totalBuffer, dataIndex, numberOfCharsReaded);     // Add temporary buffer to main buffer
                    dataIndex += numberOfCharsReaded;

                } while (true);
            }
        }

        return ret;
    }

备注从Access数据库截断为VBA字符串

2 个答案: