重新改进支持Qt4.6-Qt6.1

3rd_smtpclient/mimeattachment.cpp

@@ -0,0 +1,17 @@
+#include "mimeattachment.h"
+#include <QFileInfo>
+
+MimeAttachment::MimeAttachment(QFile *file)
+	: MimeFile(file)
+{
+}
+
+MimeAttachment::~MimeAttachment()
+{
+}
+
+void MimeAttachment::prepare()
+{
+	this->header += "Content-disposition: attachment\r\n";
+	MimeFile::prepare();
+}