关于SHAPE文件和SQL SERVER 数据库连接问题,急!!

<P><STRONG><FONT face=Tahoma size=2>        Dim pCom As New System.Data.SqlClient.Command<BR>        Dim cnn as new system.data.sqlclient.sqlconnection</FONT></STRONG></P>
<P><STRONG><FONT face=Tahoma size=2>        Dim pTable As New MapObjects2.Table<BR>        Dim yl As New MapObjects2.MapLayer<BR>        Dim dc As New MapObjects2.DataConnection<BR>        pcom.Connection = cnn<BR>        cnn.Open()<BR>        pcom.CommandType = CommandType.Text<BR>        yl.GeoDataset = dc.FindGeoDataset("station")<BR>        Dim sql As String<BR>        sql = "select * from test  "<BR>        pcom.CommandText = sql<BR>       <FONT color=#f70938> pTable.Command = pcom</FONT><BR><BR>        If yl.AddRelate("BH", pTable, "BH", True) Then<BR>               MsgBox("图层和属性关联成功")<BR>        Else<BR>            MsgBox("图层和属性关联不成功，不能模拟")<BR>        End If<BR>        cnn.Close()<BR><FONT color=#bb4444>未处理的“System.InvalidCastException”类型的异常出现在 mscorlib.dll 中。<BR><BR>其他信息: 不支持此接口 错误出现在   pTable.Command = pcom<BR>，请各位指点</FONT></FONT></STRONG></P>
<P><STRONG><FONT face=Tahoma color=#000000 size=2>---------------------------------------------------------</FONT></STRONG></P>
<P><STRONG><FONT face=Tahoma size=2>又用下面的代码,还是不能建立联结</FONT></STRONG></P>
<P>Dim dc As New MapObjects2.DataConnection</P>
<P><STRONG><FONT face=Tahoma size=2>Dim pTable As New MapObjects2.Table<BR>        Dim yl As New MapObjects2.MapLayer<BR>        Dim cnn as new system.data.sqlclient.sqlconnection</FONT></STRONG></P>
<P><STRONG><FONT face=Tahoma size=2> yl.GeoDataset = dc.FindGeoDataset("station")<BR>        pTable.Server = "10.49.2.111"<BR>        pTable.Database = "instance=rain"<BR>        pTable.User = "zdzyl"<BR>        pTable.Password = "zdzylserver"<BR>        pTable.Name = "test"</FONT></STRONG></P>
<P><STRONG><FONT face=Tahoma size=2>        If ly.AddRelate("BH", pTable, "BH", True) Then<BR>            '<BR>            MsgBox("图层和属性关联成功")<BR>            'MobjectRender(ly)<BR>        Else<BR>            MsgBox("图层和属性关联不成功，不能模拟")<BR>        End If</FONT></STRONG></P>
<P> <FONT color=#bb4444>运行结果也是"<STRONG><FONT face=Tahoma size=2>图层和属性关联不成功，不能模拟"</FONT></STRONG></FONT></P>
<P><STRONG><FONT face=Tahoma color=#bb4444 size=2>为什么建立不了关联呢?请高手指教!</FONT></STRONG><BR></P>

<P>请高手指点呀!!!自己顶一下</P>