如何得到通过属性过虑的shapefile图层？

8。3下可以用以下代码实现，可是9。0下总是报告最后一句尚未实现。怎么会事呢?
                    Dim pWorkspaceFactory As IWorkspaceFactory
                    Dim pWorkspace As IWorkspace
                    Dim pFWorkspace As IFeatureWorkspace


<P>                    Dim pfclass As IFeatureClass
                    Dim pFCContainer As IFeatureClassContainer</P>
<P>                    'Get FeatureClass to be set as datasource
                    pWorkspaceFactory = New ShapefileWorkspaceFactory
                    pWorkspace = pWorkspaceFactory.OpenFromFile(FQlayer.FilePath, 0)
                    pFWorkspace = pWorkspace</P>
<p>
<P>                    Dim pQueryDef As IQueryDef
                    pQueryDef = pFWorkspace.CreateQueryDef</P>
<P>                    pQueryDef.Tables = FQlayer.layname</P>
<P>
                    pQueryDef.WhereClause = FQlayer.Filtersql</P>
<P>                    Dim pFeatureDataset As IFeatureDataset</P>
<P>                    pFeatureDataset = pFWorkspace.OpenFeatureQuery(FQlayer.layname, pQueryDef)</P>