错误%1无法创建抽象接口- C#的实例

Question

好吧，我知道它是什么意思，但我不知道如何解决它这里是我的界面

        public interface nsIDownloadProgressListener
        {
            nsIDOMDocument getDocument();

            void setDocument(nsIDOMDocument doc);

            void OnDownloadStateChange(short state, nsIDownload aDownload);

            void OnStateChange(nsIWebProgress aWebProgress, nsIRequest aRequest, uint                                    
            aStateFlags, object aStatus, nsIDownload aDownload);

            void OnProgressChange(nsIWebProgress WbProgress, nsIRequest aReq, int         
            curSelfProgress, int maxSelfProgress, int curTotalProgress, int 
            maxTotalProgress, nsIDownload aDownload);

            void OnSecurityChange(nsIWebProgress wbProgress, nsIRequest aReq, uint 
            aState, nsIDownload aDownload);
            }

下面是我用来继承接口的类

          public class DownloadProgressListenerClass : nsIDownloadProgressListener
          {
              #region nsIDownloadProgressListener Members

              nsIDOMDocument Nothingreturned;

              public nsIDOMDocument getDocument()
              {
                  return Nothingreturned;
              }

              public void setDocument(nsIDOMDocument doc)
              {
              }

              public void OnDownloadStateChange(short state, nsIDownload aDownload)
              {
                  MessageBox.Show(aDownload.getId().ToString());
                  OnDownloadStateChange(state, aDownload);
              }

              public void OnStateChange(nsIWebProgress aWebProgress, nsIRequest aRequest, uint aStateFlags, object aStatus, nsIDownload aDownload)
              {
                  MessageBox.Show(aDownload.getId().ToString());

              }

              public void OnProgressChange(nsIWebProgress WbProgress, nsIRequest aReq, int curSelfProgress, int maxSelfProgress, int curTotalProgress, int maxTotalProgress, nsIDownload aDownload)
              {
                  MessageBox.Show(aDownload.getId().ToString());

              }

              public void OnSecurityChange(nsIWebProgress wbProgress, nsIRequest aReq, uint aState, nsIDownload aDownload)
              {
                  MessageBox.Show(aDownload.getId().ToString());

              }

              #endregion nsIDownloadProgressListener Members
          }

然后，我尝试将侦听器添加到DLManager，该侦听器应该工作并报告进度

            DownloadProgressListenerClass DLListener = new DownloadProgressListenerClass();
            DLManager = Xpcom.GetService<nsIDownloadManager>("@mozilla.org/download-manager;1");
            DLManager.addListner(DLListener);

它有什么问题吗，因为它编译正确，但是当我尝试下载一个文件时，它没有触发任何东西，也没有显示它应该显示的消息框

Answer 1

我怀疑您的addListener方法需要的接口类型是

代码行中的nsIDownloadProgressListener：

DLManager.addListner(DLListener);

如果是这样，请更改您的

DownloadProgressListenerClass DLListener = new DownloadProgressListenerClass();

转到

nsIDownloadProgressListener DLListener = new DownloadProgressListenerClass();

如果你需要解释，请告诉我。