主题：如何提取值写入文本中？

Dim str As String = ""
For Each dr As DataRow In DataTables("表A").DataRows
    str &= dr("第一列") & "," & dr("第二列") & vbcrlf
Next
msgbox(str)

 

Dim str As String = ""
For Each dr As DataRow In DataTables("表A").DataRows
    str &= dr("经度") & "," & dr("纬度") & "," & dr("高度") & vbcrlf
Next
msgbox(str)

1、是赋值，空值

 

2、等同于 str = str & dr("经度") & "," & dr("纬度") & "," & dr("高度") & vbcrlf 

 呃，不可能的 只要加了 vbcrlf，就一定会换行。我测试没问题。

  改一下，比如

 

Dim client As New System.Net.Mail.SmtpClient()
client.Host = "smtp.126.com"
client.Port = 25
client.EnableSsl = False
client.Credentials = New System.Net.NetworkCredential("lin_hailun@126.com", "6849338.")
client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network
Dim message As New System.Net.Mail.MailMessage("lin_hailun@126.com", "2450314695@qq.com")
message.Subject = "邮件测试"
message.BodyEncoding = System.Text.Encoding.UTF8

Dim content As String

content &= "这是文字" & vbcrlf
content &= "也是文字"

message.Body = content

Try
    client.Send(message)
    msgbox("发送成功")
Catch ex As Exception
    msgbox("发送失败:" & ex.message)
End Try