用程序改变Annotation 层的字体大小如何改呀？

<P>用程序改变Annotation 层的字体大小如何改呀？为什么用feature的属性FontSize字段的值不行呀？</P>
<P>如下代码，问题出在哪呀？</P>
<P>      //改变线物字体大小<BR>      if (CurrentFeatLyr.Name.ToUpper().Trim() == "L_XZDL_1")<BR>      {<BR>       IDataset pDataset=AnnoClass as IDataset;<BR>       IWorkspace pWorkspace = pDataset.Workspace;<BR>       IWorkspaceEdit pWorkspaceEdit = pWorkspace as IWorkspaceEdit;<BR>       pWorkspaceEdit.StartEditing(false);<BR>       pWorkspaceEdit.StartEditOperation();</P>
<P>       GC.Collect();<BR>       IFeatureCursor pFeatCur = AnnoClass.Search(null,true);<BR>       int FTIndex=pFeatCur.Fields.FindField("FontSize");<BR>       double FontSize=(double)numericUpDown1.Value;<BR>       IFeature pFeat;<BR>       pFeat=pFeatCur.NextFeature();<BR>       while(pFeat!=null)<BR>       {<BR>        pFeat.set_Value(FTIndex,FontSize);<BR>        pFeat.Store();<BR>        pFeat=pFeatCur.NextFeature();<BR>       }<BR>       pWorkspaceEdit.StopEditOperation();<BR>       pWorkspaceEdit.StopEditing(true);</P>
<P>      }</P>

<img src="images/post/smile/dvbbs/em02.gif" /><img src="images/post/smile/dvbbs/em02.gif" />

FontSize只读