PowerApps - If Function and drop down lists

[Arne94]

Hello,

I have 2 drops down controls.

I have 1 list connected to the 1st drop down (with only two possible selections in that drop down).

There are 2 possible lists that I want in the 2nd drop down. The list that appears for selection, I want to be dependent on the selection in the 1st drop down. (See my if function below)

If(DropDown1.Selected.Value = "Selection1", List1, List2)

It works, but list 1 only appears (as it is linked to selection1), my logic is else, use list2. But when I select Selection2 in the 1st dropdown, the List2 is blank in the 2nd dropdown.

Best regards,

Arné

[CarlosFigueira]

Do the lists List1 and List2 have similar schemas (same column names / types)? If so, then it should work. If not, then you can select a subset of each list (using AddColumns / ShowColumns / RenameColumns) that you want shown in the dropdown control that have the same schema.

For example, if I have the following two collections:

ClearCollect(
    List1;
    { Name: "John Doe"; Phone: "555-555-1111" };
    { Name: "Jane Roe"; Phone: "555-555-2222" };
    { Name: "Jim Poe"; Phone: "555-555-3333" };
    { Name: "Joan Coe"; Phone: "555-555-4444" });;
ClearCollect(
    List2;
    { Age: 29; FirstName: "Russell"; LastName: "Wilson" };
    { Age: 32; FirstName: "Marshawn"; LastName: "Lynch" };
    { Age: 30; FirstName: "Doug"; LastName: "Baldwin" };
    { Age: 36; FirstName: "John"; LastName: "Ryan" };
    { Age: 28; FirstName: "Bobby"; LastName: "Wagner" })

If I define the dropdown Items property as follows:

If(Dropdown1.Selected.Value = "List 1"; List1; List2)

Then it will not work.

We can, however, reshape the two lists so that they share the same schema, in which case the dropdown should work:

If(
    Dropdown1.Selected.Value = "List 1";
    ShowColumns(List1; "Name");
    ShowColumns(
        AddColumns(List2; "Name"; FirstName & " " & LastName);
        "Name"))

[tommyly]

It sounds like you want to do cascading dropdowns. There are two ways that I know of to do this (probably more that I do not know). I'll use city, state as an example. One way is the way you are doing, with two columns.

First off, there could be a number of reasons why your List1 and List2 are not showing up. My gut feeling is that your lists have varying column names. For example, List1 column might be "FirstName" and then List2 column might be "FullName". This would result in the first list being accepted and the second list not being accepted.

What I would do is avoid creating different lists altogether by createing an exhaustive List2 and then use filters:

1. Create collection1 as a collection; preferably in the OnStart or OnVisible event of the screen:
   

   ClearCollect(collectionList1,  
     Table({ID:1, State: "New York"}, {ID:2, State: "California"}, {ID:3, State: "Texas"})
   )

2. Create the items for List2 as an exhaustive collection, again, preferably in the OnStart or OnVisible event of the screen:

   ClearCollect(collectionList2,    
       Table(
         {ID:1, City: "New York City", State: 1},
         {ID:2, City: "Rochester", State: 1},
         {ID:3, City: "Albany", State: 1},
         {ID:4, City: "Los Angeles", State: 2},
         {ID:5, City: "San Diego", State: 2},
         {ID:6, City: "Sacramento", State: 2},
         {ID:7, City: "Dallas", State: 3},
         {ID:8, City: "Houston", State: 3},
         {ID:9, City: "Austin", State: 3},
       )
   )

   or alternatively...  combine two lists into one list:

   ClearCollect(collectionList2, List1);
   Collect(collectionList2, List2)

3. Set dropDown1.Items:

   SortByColumns(collectionList1, "City", Ascending)

4. Set dropDown2.Items:

   SortByColumns(
     Filter(collectionList2, State=dropDown1.Selected.ID),
     "City", Ascending
   )

[v-xida-msft]

Hi @Arne94,

Does the List 1 and the List 2 have same data structure?

Where do you put the formula that you provided within your second Drop down control? within Items property?

I agree with @CarlosFigueira's thought almost. If the List 1 and List 2 have same data structure, I think the formula that you provided should work.

If the List 1 and the List 2 have different data structure, and you type the formula that you provided within the Items property of the second Drop down, when you change the selection within the first Drop down, only same/common column in both lists (List 1 and List 2) could be able to accessed/displayed within the second Drop down.

Best regards,

Kris