如何通过OLE Outlook获取退回邮件诊断信息（Gupta/TeamDeveloper）

I’ve dealt with similar headaches when working with Outlook OLE in TeamDeveloper, so let’s break down how to safely identify non-delivery reports (NDRs) caused by invalid recipients, while avoiding crashes from empty date fields.

1. First, Identify NDRs Using Outlook’s Message Class #

Outlook tags bounce messages with a specific MessageClass property. For standard "recipient not found" NDRs, this is usually IPM.Note.NDR (for non-delivery reports). Start by checking this property before touching date fields—it’s a reliable way to separate bounces from regular emails upfront:

strMsgClass = OutlookItem.MessageClass
IF strMsgClass = "IPM.Note.NDR" THEN
    // This is likely a bounce message - handle it specially
    bIsNDR = TRUE
END IF

2. Safely Read Date Fields (or Avoid Them Altogether) #

The crash happens because Outlook doesn’t populate ReceivedTime or SentOn for some NDRs, and TeamDeveloper’s OLE handler throws an error when trying to read an empty date value. Here are two solid fixes:

Option A: Wrap Date Reads in Error Handling #

Use a TRY...CATCH block to catch the OLE error gracefully instead of letting it crash your app:

TRY
    dtReceived = OutlookItem.ReceivedTime
    // If we get here, the date is valid - proceed with normal logic
CATCH OLE_ERROR
    // Empty date detected - flag this as an NDR
    bIsNDR = TRUE
END TRY

Option B: Use Outlook’s PropertyAccessor for Safe Checks #

Outlook’s PropertyAccessor lets you verify if a property exists and has a value before reading it. For the ReceivedTime property, use its MAPI property tag (0x0E060040):

objPropAccessor = OutlookItem.PropertyAccessor
IF objPropAccessor.PropertyExists("http://schemas.microsoft.com/mapi/proptag/0x0E060040") THEN
    dtReceived = objPropAccessor.GetProperty("http://schemas.microsoft.com/mapi/proptag/0x0E060040")
ELSE
    // Property is missing/empty - mark as NDR
    bIsNDR = TRUE
END IF

This is more robust because it proactively checks for the property’s existence instead of reacting to an error.

3. Add Backup Checks for NDRs #

Date checks alone aren’t foolproof. Combine them with other NDR indicators to be 100% sure you’re targeting the right bounces:

• Subject Line: Look for keywords like Undeliverable: (English) or localized equivalents (e.g., 无法送达: for Chinese)
• Sender Address: NDRs usually come from system addresses like postmaster@yourdomain.com or mailer-daemon@xxx.com
• Body Content: Search for SMTP error codes like 550 5.1.1 (the standard code for "recipient does not exist")

Example of a subject check in TeamDeveloper:

strSubject = OutlookItem.Subject
IF InStr(strSubject, "Undeliverable:") > 0 THEN
    bIsNDR = TRUE
END IF

Final Workflow #

Putting it all together, your logic should follow this order:

1. Check the MessageClass to flag potential NDRs
2. Use error handling or PropertyAccessor to safely validate date fields (no more crashes)
3. Add secondary checks (subject, sender, body) to confirm it’s a "recipient not found" bounce

This approach eliminates crash risks and gives you a far more accurate way to identify the specific bounces you care about.

内容的提问来源于stack exchange，提问作者Flo