怎样获取遥感数据四个波段

<P>    IRasterLayer  pRasterLayer= new  RasterLayerClass(); <BR>   pRasterLayer=pMap.get_Layer(0) as IRasterLayer;<BR>   IRaster pRaster=pRasterLayer.Raster;<BR>   IRasterBandCollection pRasterBandCollection=pRaster as IRasterBandCollection;</P>
<P>  但只能读出三个 </P>
<P> pRasterBandCollection.Count=3</P>
<P> 怎么也读不出四个,</P>
<P>请各位看看</P>

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