Creating a PowerApp with SharePoint lists as the backend

[sloughcow]

I'm re-entering the world of Power Apps and I feel like I'm making a stupid mistake.

I have a few SharePoint lists in play. 

• SubProjects. The Subprojects list holds a list of the names of some subprojects. The important column here is the SubProjectTitle.
• MetadataModelMMMarketing. I have several project types, and each of them have different metadata requirements, so I have a couple of Sharepoint lists to enable those models. The MetadataModelMMMarketing list has a lookup column called MMMMarketingSubProject, which looks up the SubProjectTitle from the SubProjects list.

I have a screen that I want to display vertical navigation on the left, showing the full list of SubProjects. I want to be able to select a SubProject, and see the details on the right, pulled from the MetadataModelMMMArketing list, filtered on the SubProjectTitle chosen in that navigation. I think this logical join is what's causing my angst.

What I've got right now

• I've got a vertical gallery to create that navigation.
  • I've named it SubProjectNavigation.
  • The Items property for the gallery is SubProjects.
  • In that gallery I've got a visible Title, and the OnSelect property of the Title is Select(Parent).
• I've got a display form to show the details when something is selected in the gallery.
  • I've named it Details.
  • I've set the DataSource to MetadataModelMMMArketing. 
  • I've tried setting the Items property to LookUp(MetadataModelMMMarketing,MMMarketingSubProject=SubProjectNavigation.Selected.Value)
  • I've tried setting the Items property to LookUp(MetadataModelMMMarketing,MMMarketingSubProject=SubProjectNavigation.Selected.Name)
    • I've tried putting a text() function around both Value and Name.
  • I've tried setting the Items property to filter as well... 

Does anyone know what I'm doing wrong?

[poweractivate · Accepted solution]

@sloughcow 

First, it's important to remember that the "Items" property is relevant to galleries, combo boxes, and other controls that can hold multiple records, while a Form control uses the "Item" property as it's designed to display or edit a single record.

Now, in case you're confusing the properties:

You mentioned trying to set the "Items" property of a Display Form, which might be where the confusion lies, as a Form control uses the "Item" property to determine the record it displays.

To fix this, you should update your formula to set the "Item" property of the form to the selected item from your SubProjectNavigation gallery. Here's an example:

LookUp
(
   MetadataModelMMMarketing, 
   MMMMarketingSubProject.SubProjectTitle = SubProjectNavigation.Selected.SubProjectTitle
)

In case you're not confusing the properties and referring to a gallery instead:

If you're trying to set the "Items" property of a gallery (let's call it DetailsGallery) to show filtered records based on the selected item in the SubProjectNavigation gallery, then you might be facing issues with the way you're trying to match the selected item. Here's how you could adjust your formula:

Filter
(
   MetadataModelMMMarketing, 
   MMMMarketingSubProject.SubProjectTitle = SubProjectNavigation.Selected.SubProjectTitle
)

This formula should filter the items in the DetailsGallery to only those that have a matching SubProjectTitle with the selected item in the SubProjectNavigation gallery.

In both cases, please ensure that MMMMarketingSubProject.SubProjectTitle and SubProjectNavigation.Selected.SubProjectTitle are both text data types, as this could cause issues with your LookUp or Filter function if they're not.

Also note the above may be incorrect, if it's a Lookup column you may need below instead
For Item property of Details form

LookUp(MetadataModelMMMarketing, MMMMarketingSubProject.Value = SubProjectNavigation.Selected.SubProjectTitle)

or

for Items property of your DetailsGallery

Filter(MetadataModelMMMarketing, MMMMarketingSubProject.Value = SubProjectNavigation.Selected.SubProjectTitle)

See if it helps @sloughcow 

[sloughcow]

First, thank you, @poweractivate !

You're 100% right. On the form, I meant Item, not Items!

I found that, though I'd changed the Title of my SubProjects list in the modern view of SharePoint, it was still Title behind the scenes. (I updated that so I didn't have to use Title instead of SubProjectTitle), and used this formula from you (the MMMarketingSubproject column is indeed a lookup):

LookUp(MetadataModelMMMarketing, MMMMarketingSubProject.Value = SubProjectNavigation.Selected.SubProjectTitle)

I see that MMMarketingSubProject.Value is the magic for a lookup - thank you!

Progress: I no longer see an error! 
But I also don't see any results on my detail form. I get "No item to display," even though there are records in the SharePoint lists. 

I'm suspicious about that OnSelect behavior in the vertical gallery. Should the display OnSelect behavior be Select(Parent)? 

[poweractivate]

@sloughcow 

In the formula bar, and on your current formula for the Item property of your Form:

LookUp(MetadataModelMMMarketing, MMMMarketingSubProject.Value = SubProjectNavigation.Selected.SubProjectTitle)

Go ahead and try to mouse over the MMMMarketingSubProject.Value and also mouse over the SubProjectNavigation.Selected.SubProjectTitle

What do you see there?
Do they match?
Does one say "Blank"?

You may also try and mouse over 

MMMMarketingSubProject
SubProjectNavigation.Selected

See if it gives more info as well @sloughcow 

[sloughcow]

I think you're on to something, @poweractivate .

MetadataModelMMMarketing gets recognized as a table, and lights up SubProjectNavigation, both in the formula and on the screen.

MMMarketingSubProject.Value doesn't offer anything except the tooltip indicating that it's a condition of the LookUp function. 

SubProjectNavigation gets recognized as a control, and gets highlighted on the screen.

SubProjectTitle shows "SubProjectNavigation.Selected.SubProjectTitle = Blank and recognizes it as Data type: text

[poweractivate]

@sloughcow 
SubProjectNavigation.Selected

What does this show? Try and manually select the clause in formula bar
SubProjectNavigation.Selected

If it is blank too then maybe issue is simply just that not any record was selected from Gallery.

[poweractivate]

@sloughcow 

Put an extra temporary gallery somewhere on the screen where your Gallery is now.
For Items property put this

First(MetadataModelMMMarketing)

Here you can quickly check on the columns of the first item

MMMMarketingSubProject

 You may see if it also is some Record for example, has fields, has the column called Value in it, etc.
Then you can even do

First(MetadataModelMMMarketing).MMMMarketingSubProject

(if that's a Record or a Table)

You may even test the whole original LookUp you were attempting here to check on everything.

Then delete the gallery when done.

This exploits that a Gallery may also take a single Record for Items and not only a Table. It's not how you usually should use a Gallery. It may be useful to use it for debugging here sometimes.

[sloughcow]

@poweractivate Here are some screen shots, which I hope will be a whole lot clearer than my descriptions!

[poweractivate]

@sloughcow 
try and select 
SubProjectNavigation.Selected
and provide a screenshot.
Check also my advise about the 2nd temporary Gallery as you may get further there, we can't examine the left side of the equal sign directly so we should try that way to check on MMMarketingSubProject specifically. 

[sloughcow]

@poweractivate yes! I do get a record when I'm just looking for the record and not filtering based on the navigation gallery:

But then it falls apart. I'm going to try rebuilding my navigation gallery, just for fun...