Cannot get dropdown to show values from a collection

[paulinuk]

Hello

I need to have a dropdown populate its items from a collection

I have a Sharepoint list - Site where the name of a Site is stored in Title

So I load this into a collection.  This list has 

ClearCollect(
   SiteCollection,
   Site
);

My edit form has a variable with the property SiteName

This is a lookup and so is shown as a dropdown 

What do I set Items, DisplayName and DisplayValue to?

This complains saying that Title is not valid 

If I set it to just SiteCollection it doesn't work either?

Please can someone help?

Cheers

Paul

[WarrenBelz · Accepted solution]

Hi @paulinuk ,

Make the collection

ClearCollect(
   SiteCollection,
   Site.Title
);

Then the Items of the dropdown

SiteCollection

Please click Accept as solution if my post helped you solve your issue. This will help others find it more readily. It also closes the item. If the content was useful in other ways, please consider giving it Thumbs Up.

Visit my blog Practical Power Apps

[paulinuk]

Thanks this now makes the box have the expected items

However, when I have the form in add mode and select an entry from the list and post back to sharepoint the sitename is not filled?  

 Patch(
'Issue List',
ShowColumns(
Filter(
IssuesToBeAdded,
ID in colUnsavedRecords.ID
),
"ID",
"Title",
"Description",
"InternalID",
"SiteName"
);
);

[WarrenBelz]

@paulinuk ,

That is totally unrelated to your post question (and involves a different field to the one addressed there)

Patch(
   'Issue List',
   ShowColumns(
      Filter(
         IssuesToBeAdded,
         ID in colUnsavedRecords.ID
       ),
      "ID",
      "Title",
      "Description",
      "InternalID",
      "SiteName"
   )
);

When you do a Patch with this structure, all the "ShowColumns" fields need to "line up" with those in the data source in name and field type. For a test, put this on a button/icon

ClearCollect(
   colTest,
   Filter(
      IssuesToBeAdded,
      ID in colUnsavedRecords.ID
    ),
   "ID",
   "Title",
   "Description",
   "InternalID",
   "SiteName"
)

and see what is in SiteName  in the collection and if that matches the field in your IssuesToBeAdded list.

Please click Accept as solution if my post helped you solve your issue. This will help others find it more readily. It also closes the item. If the content was useful in other ways, please consider giving it Thumbs Up.

Visit my blog Practical Power Apps

[paulinuk]

ok thanks I will take a look 

SiteName in IssuesToBeAdded is a lookup column to the Site list in Sharepoint

Do I have to do something different because of that?

[WarrenBelz]

@paulinuk ,

Absolutely - you cannot patch in that structure. You will need to go back to a "traditional" patch and include the Id and Value of the Lookup column (you are way better off without this column type unless you want to interact with SharePoint directly with it)

[paulinuk]

Hello

What do you mean include the id and name?

How would I replace my patch with this approach?

I am interacting directly with sharepoint

I have security on the sites list so I am using this to secure the diary entries because I know that if a user accesses the app their sharepoint access will not populate the site name so I can use this to exclude entries the user cannot have access fk

Paul

[WarrenBelz · Accepted solution]

@paulinuk ,

OK - if you must use Lookup columns, just be prepared for the grief (also beyond this) they at times cause in Power Apps (I have not used them in many years).

A Lookup field is actually a Table containing two fields - Value and Id. The first is simply the value you have chosen, but the second is the ID (note the capitalisation of these two) of the value looked up in the other list. When you patch back to the primary list, the Id is actually the element you need to get right.

The syntax is

LookupFieldName: {Value:TextValueHere, Id:NumberValueHere}

obviously used in conjunction with patching the rest of the fields.

Please click Accept as solution if my post helped you solve your issue. This will help others find it more readily. It also closes the item. If the content was useful in other ways, please consider giving it Thumbs Up.

Visit my blog Practical Power Apps

[paulinuk]

ok thanks 

What problems can happen with lookup fields?

Could these cause apps to be unreliable running offline?  

As posted previously I have an issue where sometimes when running offline the buttons on my app do nothing

I will mark the post above as a solution for this issue

[WarrenBelz]

Hi @paulinuk ,

They are a historical field type (SharePoint has been around a lot longer than Power Apps) that was designed with the SharePoint/InfoPath interface in mind. They are (as I mentioned) a complex field type with one of the elements (Id) coming from another list. You will have issues writing back on anything other than a combo box based purely on the standard choices, and (among other things) you cannot sort or group by them in a Delegable manner.

The real point however is that you can do exactly the same lookup in Power apps and store the result in a Single Line of Text and then everything (that can) becomes Delegable and much simpler to read from and write to.