# Perspective 8.1.xx Dropdown list - Use VALUE returned

**URL:** <https://forum.inductiveautomation.com/t/perspective-8-1-xx-dropdown-list-use-value-returned/49726>\
**Category:** Ignition\
**Created:** [August 9, 2021, 8:26pm UTC](https://forum.inductiveautomation.com/t/perspective-8-1-xx-dropdown-list-use-value-returned/49726 "2021-08-09T20:26:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![dwoo](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@dwoo](https://forum.inductiveautomation.com/u/dwoo)\
**Post date:** [August 9, 2021, 8:26pm UTC](https://forum.inductiveautomation.com/t/perspective-8-1-xx-dropdown-list-use-value-returned/49726/1 "2021-08-09T20:26:02Z")

</div>

I have a perspective dropdown box being populated (options parameter) by a nx1 dataset returned from a named query. The list looks fine and the selected “value” displays correctly. However when I try to use the “value” property and assign it or use it in a named query call I get an error of  
“…Cannot coerce value ‘set([value])’ into type:…”

below is the code line from the Change Script for the VALUE property that’s trying to use the selected value

dbdata = system.db.runNamedQuery(“Get\_Stations\_ID\_Name”,{currentValue.value})

where the namedQuery paremeter shoud be an INT4

dataset used to populate dropdown list:  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/c/b/cb6068e6de43b360de487d27fdf98ac53a32503a.png)

FULL ERROR message:

15:30:39.170 [AWT-EventQueue-0] ERROR com.inductiveautomation.ignition.client.util.gui.ErrorUtil - Error running property change script on Dropdown.props.value: Traceback (most recent call last):  
File “function:valueChanged”, line 6, in valueChanged  
at com.inductiveautomation.ignition.common.TypeUtilities.coerce(TypeUtilities.java:1422)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.coerce(PyArgumentMap.java:130)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:82)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:40)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.interpretWithOptionalProject(GatewayDBUtilities.java:466)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.runNamedQuery(GatewayDBUtilities.java:375)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)  
at java.base/java.lang.reflect.Method.invoke(Unknown Source)  
java.lang.ClassCastException: java.lang.ClassCastException: Cannot coerce value ‘set([3L])’ into type: interface java.util.Map

com.inductiveautomation.ignition.common.GenericTransferrableException: Traceback (most recent call last):  
File “function:valueChanged”, line 6, in valueChanged  
at com.inductiveautomation.ignition.common.TypeUtilities.coerce(TypeUtilities.java:1422)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.coerce(PyArgumentMap.java:130)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:82)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:40)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.interpretWithOptionalProject(GatewayDBUtilities.java:466)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.runNamedQuery(GatewayDBUtilities.java:375)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)  
at java.base/java.lang.reflect.Method.invoke(Unknown Source)  
java.lang.ClassCastException: java.lang.ClassCastException: Cannot coerce value ‘set([3L])’ into type: interface java.util.Map

```
at org.python.core.Py.JavaError(Py.java:552)
at org.python.core.Py.JavaError(Py.java:543)
at org.python.core.PyReflectedFunction. __call__ (PyReflectedFunction.java:190)
at com.inductiveautomation.ignition.common.script.ScriptManager$ReflectedInstanceFunction. __call__ (ScriptManager.java:523)
at org.python.core.PyObject. __call__ (PyObject.java:497)
at org.python.core.PyObject. __call__ (PyObject.java:501)
at org.python.pycode._pyx25.valueChanged$1(<function:valueChanged>:11)
at org.python.pycode._pyx25.call_function(<function:valueChanged>)
at org.python.core.PyTableCode.call(PyTableCode.java:171)
at org.python.core.PyBaseCode.call(PyBaseCode.java:308)
at org.python.core.PyFunction.function ___call__ (PyFunction.java:471)
at org.python.core.PyFunction. __call__ (PyFunction.java:466)
at org.python.core.PyFunction. __call__ (PyFunction.java:461)
at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:821)
at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:805)
at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$TrackingProjectScriptManager.runFunction(ProjectScriptLifecycle.java:687)
at com.inductiveautomation.ignition.common.script.ScriptManager$ScriptFunctionImpl.invoke(ScriptManager.java:964)
at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$AutoRecompilingScriptFunction.invoke(ProjectScriptLifecycle.java:752)
at com.inductiveautomation.perspective.gateway.script.ScriptFunctionHelper.invoke(ScriptFunctionHelper.java:106)
at com.inductiveautomation.perspective.gateway.model.PropertyChangeScript.onValueChanged(PropertyChangeScript.java:123)
at com.inductiveautomation.perspective.gateway.property.PropertyTree$Notifier.run(PropertyTree.java:183)
at com.inductiveautomation.ignition.common.util.ExecutionQueue$PollAndExecute.run(ExecutionQueue.java:210)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.base/java.lang.Thread.run(Unknown Source)

```

Caused by: com.inductiveautomation.ignition.common.GenericTransferrableException: Traceback (most recent call last):  
File “function:valueChanged”, line 6, in valueChanged  
at com.inductiveautomation.ignition.common.TypeUtilities.coerce(TypeUtilities.java:1422)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.coerce(PyArgumentMap.java:130)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:82)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:40)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.interpretWithOptionalProject(GatewayDBUtilities.java:466)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.runNamedQuery(GatewayDBUtilities.java:375)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)  
at java.base/java.lang.reflect.Method.invoke(Unknown Source)  
java.lang.ClassCastException: java.lang.ClassCastException: Cannot coerce value ‘set([3L])’ into type: interface java.util.Map

```
... 25 common frames omitted

```

Caused by: com.inductiveautomation.ignition.common.GenericTransferrableException: Cannot coerce value ‘set([3L])’ into type: interface java.util.Map  
at com.inductiveautomation.ignition.common.TypeUtilities.coerce(TypeUtilities.java:1422)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.coerce(PyArgumentMap.java:130)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:82)  
at com.inductiveautomation.ignition.common.script.builtin.PyArgumentMap.interpretPyArgs(PyArgumentMap.java:40)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.interpretWithOptionalProject(GatewayDBUtilities.java:466)  
at com.inductiveautomation.ignition.gateway.script.GatewayDBUtilities.runNamedQuery(GatewayDBUtilities.java:375)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)  
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)  
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)  
at java.base/java.lang.reflect.Method.invoke(Unknown Source)  
at org.python.core.PyReflectedFunction. **call** (PyReflectedFunction.java:188)  
… 22 common frames omitted

---

<div class="post-metadata">

**Author:** ![paul-griffith](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/paul-griffith/32/37249_2.png) [@paul-griffith](https://forum.inductiveautomation.com/u/paul-griffith)\
**Post date:** [August 9, 2021, 8:45pm UTC](https://forum.inductiveautomation.com/t/perspective-8-1-xx-dropdown-list-use-value-returned/49726/2 "2021-08-09T20:45:21Z")

</div>

> [@dwoo](#):
>
> `dbdata = system.db.runNamedQuery(“Get_Stations_ID_Name”,{currentValue.value})`

> [@dwoo](#):
>
> Caused by: com.inductiveautomation.ignition.common.GenericTransferrableException: Cannot coerce value ‘set([3L])’ into type: interface java.util.Map

In Python, `{}` around a comma-separated sequence of literals creates a _set_. `system.db.runNamedQuery` requires you to pass a _dictionary_ of key: value pairs; e.g.:  
`dbdata = system.db.runNamedQuery(“Get_Stations_ID_Name”,{"paramName": currentValue.value})`  
You'll need to use the appropriate parameter name(s) for your named query.

---

<div class="post-metadata">

**Author:** ![dwoo](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@dwoo](https://forum.inductiveautomation.com/u/dwoo)\
**Post date:** [August 10, 2021, 12:40pm UTC](https://forum.inductiveautomation.com/t/perspective-8-1-xx-dropdown-list-use-value-returned/49726/3 "2021-08-10T12:40:05Z")

</div>

Thanks that was it…semi-newbie to python… 😅