# Data Type Member

**URL:** <https://forum.inductiveautomation.com/t/data-type-member/8924>\
**Category:** Ignition\
**Created:** [August 19, 2014, 3:12pm UTC](https://forum.inductiveautomation.com/t/data-type-member/8924 "2014-08-19T15:12:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![marioquark](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@marioquark](https://forum.inductiveautomation.com/u/marioquark)\
**Post date:** [August 19, 2014, 3:12pm UTC](https://forum.inductiveautomation.com/t/data-type-member/8924/1 "2014-08-19T15:12:14Z")

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I suppose there’s something wrong with Strings parameters in expressions in UDTs.  
I’ve created a Custom Data Type tag with an Expression Tag inside, giving this Expression:

```auto
toString({MyVar})
```

where MyVar is an UDT parameter

Now, if MyVar is a Integer, it works great.  
If it’s a String, Ignition gives me an Evaluation error. ☹

I’ve tried also

```auto
toStr({MyVar})
```

and

```auto
{MyVar}
```

but it doesn’t work…  
Any suggestion?

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<div class="post-metadata">

**Author:** ![adamaustin](https://avatars.discourse-cdn.com/v4/letter/a/5f8ce5/32.png) [@adamaustin](https://forum.inductiveautomation.com/u/adamaustin)\
**Post date:** [August 21, 2014, 2:20pm UTC](https://forum.inductiveautomation.com/t/data-type-member/8924/2 "2014-08-21T14:20:13Z")

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It looks like UDTs are slightly different in how they evaluate expressions (using Ignition 7.6.6). As a work around you could try using this:

```auto
toString('{MyVar}')
```

---

<div class="post-metadata">

**Author:** ![marioquark](https://avatars.discourse-cdn.com/v4/letter/m/22d042/32.png) [@marioquark](https://forum.inductiveautomation.com/u/marioquark)\
**Post date:** [August 21, 2014, 4:30pm UTC](https://forum.inductiveautomation.com/t/data-type-member/8924/3 "2014-08-21T16:30:06Z")

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IT WORKS ![:thumb_right:](https://us1.discourse-cdn.com/inductiveautomation/original/1X/2026e28c0c425034352c1b75807edf956adc75f4.gif ":thumb\_right:")  
Thank you!