What is collection & How to manage a collection in PowerApps ?

In the last article we learned about the different controls which exist in PowerApps although there are some more controls which we will discuss going forward before jumping into remaining controls let’s discuss here the most important part Collection.

What is collection?

A collection is used to store data that can be used in your app or we can say a collection is a group of items that are similar. For example, Student data collection where the collection will store student first name, last name and other information about the student.

To see it practically let’s open PowerApps editor and add a new screen and OnStart function create a collection.

Now to create a collection in PowerApps we have  “Collection” function in PowerApp and syntax is as follows 

Collect(Collectionname, items)

So, Student collection can be defined as follow.

Collect(StudentCollection,      {Name:”Rajat”,LastName:”Jaiswal”},   {Name:”Sandeep”,LastName:”Jain”})

OnStartCollectionNew

So, we have created our first collection. To view this in action add any control you want here we are using Gallery control.

AddGalControl

Once you added this control you will find the data properties and we can see our created collection which is “StudentCollection

StudentCollection

Here we can assign  the title and subtitle  properties of the gallery with the property Name  & LastName of our newly StudentCollection.. Just Save the application at this point and reload the app again.

You will find the following screen.

DataWithGallary

We can check our newly created collection by file option as shown below

StudentCollection_001

In this way, we can create a collection. Now, the next question is how to ADD/EDIT/Remove in the collection. So, let’s understand this now.

Add Collection

Just drag-drop textboxes, labels, and a button to add the data to the collection as shown below.  On Add, button onSelect write  below function

addCollection

Now, when you run and click on Add button. You can see the Record appears in your gallery as shown in below figure.

Collection Add

Remove Collection

Now, In the next step, we will delete the record from the collection.

The syntax of this is very simple

Remove (CollectionName,item)

Now, to achieve this add a delete icon in the gallery as shown in below figure.

DeleteCollection

On select of delete icon, we can write  Remove(StudentCollection, This.Item)

Here This.Item is selected item of the gallery to which we need to delete from the collection.

Now,  What if we want to delete the entire collection? then in such case, we have

Clear Collection

The syntax is very simple Clear(CollectionName)

So in our case, we have to write Clear(StudentCollection)

Now, to Edit a particular item in a collection the first this is select the item in the text box which we want to edit and to achieve this we bind the textbox by Gallery’s selected item as shown in below figure.

Selectcollection

Once you have done with this  then on Update button we can write Patch collection function as shown below

PatchSection

So the syntax is very simple

Patch(StudentCollection,Gallery1.SelectedItem, {Name:TextInput4.Text,LastName:TextInput5.Text})

so in this way, we can update the specific item (As shown above we updated only selected item from Gallery).

So, In this session, we understood Collection, add an item in the collection, Remove function to remove a specific item from the collection, Clear Collection to delete entire items from the collection and none other than Patch function to edit the collection.

RJ

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