备忘录从Access数据库截断为VBA字符串

Question

我的Access（2003）数据库中有一个备注字段，用于存储来自Outlook（约750个字符）的文件夹的EntryID。我试图找回那种串一些邮件移动到该文件夹​​ID与此代码：

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 

的target VAR只有第252个字符，而不是748在这种情况下。有趣的是，如果没有其他可用的相同〜255个首字符的文件夹，Outlook仍然会找到正确的文件夹。但在某些情况下，它会崩溃，因为有不止一个。我正在使用记录集从数据库中获取备忘录。这是我的SQL：

SELECT EntryID FROM Folder 

我终于找到了这种行为的一些信息：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定的内容，因为您可以看到...

为什么它仍然被截断？

原始备忘录/字符串中的数据库：

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

截断备忘录/对象/场/ SQL查询字符串后：

00000000CE5B922DF5D7654C993FFDB4FF79A7A00100000057010000307E7E2D317E305C307E4C6976656C696E6B204851457E307E2D315C307E4C6976656C696E6B204851457E2D357E305C307E4C6976656C696E6B204851457E313233373235387E2D355C307E4C6976656C696E6B204851457E3130323336333431

Answer 1

在你的链接显示此768,16工作

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

我已经实现此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; 
    }