"File Path Control" default Value

[NiCoder]

Hi - How do we set or change the default value for "File Path Control" (Control --> String & Path ---> File Path Control)?

I typed the default path into the control field on the front pannel and save the VI file.  The value gone when I reopen the file.

[DHerron]

Right click on the control, go to Data Operations>>Make Current Value Default

[NiCoder]

How do we set to NOT valid the path value?

[Darin.K]

I would drop a Not A Path constant on the BD, right-click and Change to Control.  The default value is now set for you.

If you use Modern controls you can click on the % glyph and choose Not A Path, but I use System controls so that is why I go the constant route (plus the auto default setting is nice)

[JimChretz]

By the way, I realize I never paid attention that there's a difference between Not a path and Empty path... Why?

[Norbert_B]

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@Jimmy.chretien wrote:

[...] difference between Not a path and Empty path... Why?

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Not a Path is a specific value for the path (<Not a Path>).

Developers should use this to prevent situations in applications, where a user has to select a path before performing an action (e.g. saving a file). If the user skips the path selection, the application still has "Not a Path" and can prevent errors and tell the user to select the path (error handling!).

Norbert

[JimChretz]

If it returns empty path, the developer can easilly do the same error handling, I don't see the point....

[JÞB]

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@Jimmy.chretien wrote:

If it returns empty path, the developer can easilly do the same error handling, I don't see the point....

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Not as easilly since an empty path returns F for the comparison

[Darin.K]

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@Jimmy.chretien wrote:

If it returns empty path, the developer can easilly do the same error handling, I don't see the point....

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The empty path on Mac/Linux is the root of the file system.  When you write paths such as /path/path it is actually (empty)/path/path.  The upshot is that the empty path is perfectly valid on those systems and not really a useful sentinel value.  <Not A Path> is such a sentinel.

[JimChretz]

There is a "Empty String/Path?" function in LabVIEW.

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@JÞB wrote:

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@Jimmy.chretien wrote:

If it returns empty path, the developer can easilly do the same error handling, I don't see the point....

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Not as easilly since an empty path returns F for the comparison

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