急!!!关于soNetworkAnalystEx.Path

<P>SuperMapLib.soGeoLineM lineM = null;</P>
<P>axSuperAnalyst1.Connect(axSuperWorkspace1.CtlHandle);</P>
<P>SuperAnalystLib.soNetworkAnalystEx analystEx = axSuperAnalyst1.NetworkAnalyst;<BR>lineM = analystEx.Path(points, SuperAnalystLib.seFindPathType.scpFPTMinEdgesSum);</P>
<P>为何每次返回都为NULL?????还要设置其他东西吗?</P>