如何判断一个图层是shape图层

利用AB+arcENgine 开发时,如何判断一个图层是shape图层?谢谢!

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<H1>IFeatureLayer.<FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> Property  [C#]</H1></DIV>
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<H4>See Also</H4><a href="ms-help://ESRI.ArcGIS/esriCarto/html/IFeatureLayer.htm" target="_blank" >IFeatureLayer Interface</A></DIV>
<DIV><B>Language</B>
<UL>
<LI><a href="" target="_blank" >C#</A><BR>
<LI><a href="" target="_blank" >Visual Basic .NET</A><BR>
<LI><a href="" target="_blank" >Show All</A></LI></UL></DIV>
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<P>Data source type. </P><PRE none">[Visual Basic .NET]
<B>Public Property <FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> As </B><a>String</A></B></PRE><PRE block">[C#]
<B>public </B><a>string</A> <B><FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> {get; set;}</B></PRE>
<H4>Product Availability</H4>
<DIV>Available with ArcGIS Engine, ArcGIS Desktop, and ArcGIS Server.</DIV>
<H4>Description</H4>
<P>Describes the type of data referenced by the feature layer. In ArcMap and ArcCatalog this description appears on the layer's properties dialog on the Source tab after "Data Type:"</P>
<H4>Remarks</H4>
<DIV class=tableDiv>By default, the <STRONG><FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> </STRONG>for a layer matches the value returned by <STRONG>IDataset::Category </STRONG>when you access the layer's feature class through <STRONG>IDataset</STRONG>. You can set a layer's <STRONG><FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> </STRONG>to any string.</DIV>
<P>Here is a list of default values for <STRONG><FONT style="BACKGROUND-COLOR: #0a246a" color=#ffffff>DataSourceType</FONT> </STRONG>for common feature layer types:</P>
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<TABLE>

<TR>
<TH>Layer Type</TH>
<TH>Value</TH>
<TR>
<TD>Personal Geodatabase</TD>
<TD>"Personal Geodatabase Feature Class"</TD></TR>
<TR>
<TD>SDE</TD>
<TD>"SDE Feature Class"</TD></TR>
<TR>
<TD>Shapefile</TD>
<TD>"Shapefile Feature Class"</TD></TR>
<TR>
<TD>ArcInfo or PC ArcInfo Coverage (annotation)</TD>
<TD>"Annotation Feature Class"</TD></TR>
<TR>
<TD>ArcInfo or PC ArcInfo Coverage (point)</TD>
<TD>"Point Feature Class"</TD></TR>
<TR>
<TD>ArcInfo or PC ArcInfo Coverage (line)</TD>
<TD>"Arc Feature Class"</TD></TR>
<TR>
<TD>ArcInfo or PC ArcInfo Coverage (polygon)</TD>
<TD>"Polygon Feature Class"</TD></TR>
<TR>
<TD>Edge</TD>
<TD>"StreetMap Feature Class"</TD></TR>
<TR>
<TD>CAD (annotation)</TD>
<TD>"CAD Annotation Feature Class"</TD></TR>
<TR>
<TD>CAD (point)</TD>
<TD>"CAD Point Feature Class"</TD></TR>
<TR>
<TD>CAD (line)</TD>
<TD>"CAD Polyline Feature Class"</TD></TR>
<TR>
<TD>CAD (polygon)</TD>
<TD>"CAD Polygon Feature Class"</TD></TR></TABLE></DIV></DIV></DIV>

<P>把这个图层强制转换成IFeatuerLayer，如果转换失败就不是shape几何类型图层。如IFeatureLayer iFeatureLyr = iLyr as IFeatureLayer;</P>
<P>if(iFeatureLyr == null)...</P>