server error in '/' application.

object reference not set to an instance of an object.

description: an unhandled exception occurred during the execution of the current web request. please review the stack trace for more information about the error and where it originated in the code.

exception details: system.nullreferenceexception: object reference not set to an instance of an object.

source error:

line 34:     //定义栏目id
line 35:     var ab_navid = "4";
line 36:     var menuid = <%#pagecolumn.columnid.toint()%>;
line 37: </script>
line 38: </head>

source file: d:\szsegy201709205232\hyjk\index_17.aspx    line: 36

stack trace:

[nullreferenceexception: object reference not set to an instance of an object.]
   asp.hyjk_index_17_aspx.__databind__control3(object sender, eventargs e) in d:\szsegy201709205232\hyjk\index_17.aspx:36
   system.web.ui.control.ondatabinding(eventargs e) +92
   system.web.ui.control.databind(boolean raiseondatabinding) +85
   system.web.ui.control.databind() +15
   system.web.ui.control.databindchildren() +187
   system.web.ui.control.databind(boolean raiseondatabinding) +94
   system.web.ui.control.databind() +15
   asp.hyjk_index_17_aspx.page_load(object sender, eventargs e) in d:\szsegy201709205232\hyjk\index_17.aspx:26
   system.web.util.callieventhandlerdelegateproxy.callback(object sender, eventargs e) +51
   system.web.ui.control.onload(eventargs e) +92
   system.web.ui.control.loadrecursive() +54 includestagesbeforeasyncpoint, boolean includestagesafterasyncpoint) +772

version information: microsoft .net framework version:4.0.30319; version:4.0.30319.34280