[求助]c#编写InsertFeature程序

<P>要用C＃写代码向一个featureclass里加入一个feature</P>
<P>可是运行总是出错</P>
<P>请哪位帮我看看</P>
<P>private void button1_Click(object sender, System.EventArgs e)
  {
   IWorkspace ws = null;
   IWorkspaceFactory wsf = new AccessWorkspaceFactoryClass();
   IFeatureClass fc;
   string geodbname＝@"E:<a href='http://www.gisempire.com/bbs/mailt=@"e:/' target="_blank" ><FONT color=#000000>\</FONT></A>首都机场\sdairport.mdb";
    
   ws = wsf.OpenFromFile(geodbname,0);
   IFeatureWorkspace fws=(IFeatureWorkspace)ws;</P>
<P>   fc =fws.OpenFeatureClass("allobjects");
    
   //开始编辑
   IFeatureBuffer featBuffer=fc.CreateFeatureBuffer();
   IWorkspaceEdit workspaceEdit;
   workspaceEdit =(IWorkspaceEdit) ws;
      
   workspaceEdit.StartEditing (true);
   workspaceEdit.StartEditOperation();</P>
<P>   //以下生成新feature
   IFeatureCursor featCursor= fc.Insert(true);
   IFeature feat = (IFeature)featBuffer;</P>
<P>   IPoint point;
   IGeometry geometry;
   object q;
   point=new PointClass();
   point.PutCoords(120,30);
   geometry=(IGeometry)point;
   featBuffer.Shape=geometry;
    
<FONT color=#2222dd>   featBuffer.set_Value(2,1);</FONT>
   q=featCursor.InsertFeature(featBuffer);
   featCursor.Flush();</P>
<P>   workspaceEdit.StopEditOperation();
   workspaceEdit.StopEditing (true);</P>
<P>  }</P>
<P>运行到蓝色的代码，就出现异常</P>
<P><FONT color=#d52b6f>未处理的“System.Runtime.InteropServices.COMException”类型的异常出现在 test.exe 中。其他信息: 这个集合中找不到此项目。</FONT></P>
<P><FONT color=#000000>谢谢了</FONT></P>
<P><FONT color=#d52b6f></FONT></P>

<P> 我曾经也出现过这种错误，后来使用IEditor就行了</P><P>　UID pUid = new UIDClass();
    pUid.Value = "esriEditor.Editor";
    IEditor pEditor = null;
    pEditor = m_pApp.FindExtensionByCLSID(pUid) as IEditor;</P><P>　先设置pEditor开始编辑,然后开始更新要素<FONT color=#2222dd>featBuffer.set_Value(2,1);</FONT></P><P><FONT color=#2222dd>使用</FONT><FONT color=#000000>IWorkspaceEdit 设置开始编辑就不行，不知为什么！</FONT></P>

<P>   IFeature pfeature = pFeatureClass.CreateFeature
   Set pfeature.Shape = pGeometry
   pfeature.Store
</P><P>看看行不行！</P>

你要插入要素的要素类“allobjects”有几个字段？字段索引为2的字段是否存在？如果存在，该字段类型是否为数值型的？