I used ITransformationOp.Clip method, it's ok for the first 2 times, but the "ERROR 010092: Invalid output extent." began to occur from the 3rd time. So strange problems! Why? Thanks!
Thanks Nahed! I saw that solution on the website. But May be it is not the end result. My code is as following.
public IRaster RasterClip (IRasterLayer pRasterLayer, IEnvelope pExtent)
{
IRaster pRaster = pRasterLayer.Raster;
IRasterProps pProps = pRaster as IRasterProps;
object cellSizeProvider = pProps.MeanCellSize().X;
IGeoDataset pInputDataset = pRaster as IGeoDataset;
IGeoDataset pOutputDataset = pTransformionOp.Clip(pInputDataset, pExtent);
IRaster clipRaster;
clipRaster = pOutputDataset as IRaster;
}