# How can I do validation for datetime input component?

**URL:** <https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132>\
**Category:** General Discussion\
**Tags:** perspective\
**Created:** [March 16, 2020, 5:59pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132 "2020-03-16T17:59:34Z")\
**Posts on this page:** 8\
**Page:** 1

<div class="post-metadata">

**Author:** ![ptchanchal](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@ptchanchal](https://forum.inductiveautomation.com/u/ptchanchal)\
**Post date:** [March 16, 2020, 5:59pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/1 "2020-03-16T17:59:34Z")

</div>

I want to check whether user picked date from datetime input component on a button click  
I tried following codes:  
if isNull(self.session.custom.expenseSelectDate):  
if self.session.custom.expenseSelectDate == null:  
if self.session.custom.expenseSelectDate == “null”:  
if self.session.custom.expenseSelectDate == “”:  
if self.session.custom.expenseSelectDate == 0:

none of them seems wokring

Thank you.

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<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:** [March 16, 2020, 7:07pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/2 "2020-03-16T19:07:29Z")

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Try just `if self.session.custom.expenseSelectDate:`.  
Python uses the special singleton instance `None` to represent no value/null.  
Literal `null` is a syntax error unless you’ve defined a variable `null` in scope.  
`== "null"` is comparing against the literal string `"null"`.  
`== ""` is comparing against an empty string.  
`== 0` is checking for exact equality with 0; not a ‘falsey’ comparison.

If you omit all operators, Python’s `if` statement automatically checks for ‘truth’; the following statements are essentially equivalent:

```python
x = 1
if True:
if x:
if x == True:
if bool(x):
if bool(x) == True:

```

Python’s `None` singleton is ‘falsey’, so you can simply:

```auto
if x:

```

Which will fail if x is None. Or, the recommended style, which is more explicit:

```auto
if x is not None:

```

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<div class="post-metadata">

**Author:** ![ptchanchal](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@ptchanchal](https://forum.inductiveautomation.com/u/ptchanchal)\
**Post date:** [March 16, 2020, 7:34pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/3 "2020-03-16T19:34:32Z")

</div>

![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/9/971cee9fe82fce88508e44c547966bd026ee358c.png)

Still not working

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<div class="post-metadata">

**Author:** ![pturmel](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/pturmel/32/3295_2.png) [@pturmel](https://forum.inductiveautomation.com/u/pturmel)\
**Post date:** [March 16, 2020, 7:39pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/4 "2020-03-16T19:39:01Z")

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You might want to add some logging so you can see what you really have in `self.session.custom.expenseSelectDate`.

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<div class="post-metadata">

**Author:** ![ptchanchal](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@ptchanchal](https://forum.inductiveautomation.com/u/ptchanchal)\
**Post date:** [March 16, 2020, 7:43pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/5 "2020-03-16T19:43:15Z")

</div>

Its changing color as required on submit since its checking for true condition i want to check for false condition, how can i do that ?

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<div class="post-metadata">

**Author:** ![ptchanchal](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@ptchanchal](https://forum.inductiveautomation.com/u/ptchanchal)\
**Post date:** [March 16, 2020, 7:45pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/6 "2020-03-16T19:45:33Z")

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![image](https://us1.discourse-cdn.com/inductiveautomation/original/2X/1/14d574a9bc40fd62f3a2c17dcc4c0563462231d7.png)

its null in log there were no errors

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<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:** [March 16, 2020, 10:32pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/7 "2020-03-16T22:32:02Z")

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Use `not`:

```auto
if not self.session.custom.expenseSelectDate:
    # do something if it's not set

```

---

<div class="post-metadata">

**Author:** ![ptchanchal](https://avatars.discourse-cdn.com/v4/letter/p/f9ae1b/32.png) [@ptchanchal](https://forum.inductiveautomation.com/u/ptchanchal)\
**Post date:** [March 17, 2020, 1:00pm UTC](https://forum.inductiveautomation.com/t/how-can-i-do-validation-for-datetime-input-component/33132/8 "2020-03-17T13:00:37Z")

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this worked for me:

if self.session.custom.expenseSelectDate is None:

Thank you