# 1 业务场景
适用于需要取消附件上传的场景
# 2 解决方案
可以通过附件上传前事件 BeforeAttachmentUploadListener 取消附件的上传
# 3 操作步骤
代码示例如下
```java
public class AttachmentDemand_BeforeUpload extends AbstractFormPlugin implements BeforeAttachmentUploadListener {
private static final String BOS_ATTACHMENT = "bos-attachment";
//附件字段
private final static String KEY_ATTACHMENTFILED = "my_attfield";
//附件面板
private final static String KEY_ATTACHMENTPANEL = "attachmentpanel";
@Override
public void registerListener(EventObject e) {
AttachmentEdit attachmentEdit = this.getView().getControl(KEY_ATTACHMENTFILED);
AttachmentPanel attachmentPanel = this.getView().getControl(KEY_ATTACHMENTPANEL);
//监听上传前事件
attachmentEdit.addBeforeUploadListener(this);
attachme
