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- Getting Started
- Demo apps
- How To
- Notifications
- Using VB Expressions
- Designing your App
- Designing your app with Autopilot
- Events and Rules
- Rule: If-Then-Else
- Rule: Open a Page
- Rule: Open URL
- Rule: Close Pop-Over/Bottom Sheet
- Rule: Log Message
- Rule: Show Message
- Rule: Show/Hide Spinner
- Rule: Set Value
- Rule: Start Process
- Rule: Reset Values
- Rule: Upload File to Storage Bucket
- Rule: Download File From Storage Bucket
- Rule: Create Entity Record
- Rule: Update Entity Record
- Rule: Delete Entity Record
- Rule: Add to Queue
- Rule: Trigger workflow
- Rule: Submit Action
- Leveraging RPA in your App
- Leveraging Entities in Your App
- Leveraging Queues in Your App
- Leveraging Media in your app
- Leveraging Actions in your app
- Leveraging Connections in your apps
- Apps in Studio Web
- Application Lifecycle Management (ALM)
- UiPath First-Party Apps
- Basic Troubleshooting Guide
important :
For documentation on app projects in Studio Web, refer to the App Projects chapter in the Studio Web documentation: https://docs.uipath.com/studio-web/automation-cloud/latest/user-guide/apps-in-studio-web.

Apps User Guide
Last updated Oct 29, 2025
This page contains VB expressions that you may find useful while building your app.
We grouped several of these functions in a public app, so you can try out them out and see how they behave.
The
Where() function returns a zero-based array containing a subset of a string array based on a specified filter criteria.
Assume you have a variable called
words defined as List(Of String) = {"apple", "banana", "cherry", "date"}.
To get the list of words that contain the letter "a", apply the
Where() function as follows:
words.Where(Function(w) w.Contains("a")).ToList()words.Where(Function(w) w.Contains("a")).ToList()The output is
{"apple", "banana", "date"}.
The
Select() function creates a new array that contains the results of applying a lambda expression to each element in the source array.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the list of numbers multiplied by themselves, apply the The output is
Select() function as follows:numbers.Select(Function(n) n * n).ToArray()numbers.Select(Function(n) n * n).ToArray(){1, 4, 9, 16, 25}.
The
Aggregate() function performs calculations over all the elements in an array and returns a single value. This function can be useful
in aggregating multiple values inside a column.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the sum of all the numbers in the array, apply the Aggregate() function as follows:The output is
Dim sum = numbers.Aggregate(Function(acc, n) acc + n)Dim sum = numbers.Aggregate(Function(acc, n) acc + n)15.
The
GroupBy() function groups elements in a sequence by a key selector function.
Assume you have a variable called
words defined as String() = {"apple", "banana", "cherry", "date"}.
To group the words by the first letter, which is the key selector function, apply the The output is
GroupBy() function as follows:words.GroupBy(Function(w) w(0))words.GroupBy(Function(w) w(0)){ {"a", "apple", "date"}, {"b", "banana"}, {"c", "cherry"} }.
The
OrderBy() and OrderByDescending() functions sort elements in a sequence based on a key selector function.
Assume you have a variable called
words defined as String() = {"apple", "banana", "cherry", "date"}.
To order the words by their length, which is the key selector function, apply the The output is
OrderBy() function as follows:words.OrderBy(Function(w) w.Length).ToArray()words.OrderBy(Function(w) w.Length).ToArray()
{"date", "apple", "cherry", "banana"}.
The
Join() function combines elements in two sequences based on a key selector function.
Assume you have two variables:
-
namesdefined asString() = {"John", "Jane", "Joe"} -
agesdefined asInteger() = {25, 30, 35}
To combine the elements in the first sequence with the elements in the second sequence, apply the The output is
Join() function as follows:names.Join(ages, Function(name) name(0), Function(age) age Mod 10, Function(name, age) $"{name}: {age}")names.Join(ages, Function(name) name(0), Function(age) age Mod 10, Function(name, age) $"{name}: {age}")
{"John: 25", "Jane: 30", "Joe: 35"}.
The
First() function returns the first element in a sequence that satisfies a specified condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the first even number in the sequence, apply the The output is
First() function as follows:numbers.First(Function(n) n Mod 2 = 0)numbers.First(Function(n) n Mod 2 = 0)2.
The
FirstOrDefault() function returns the first element, or a default value if no element satisfies the condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the first odd number in the sequence, apply the The output is
FirstOrDefault() function as follows:numbers.FirstOrDefault(Function(n) n Mod 2 = 1)numbers.FirstOrDefault(Function(n) n Mod 2 = 1)1.
The
Last() function returns the last element in a sequence that satisfies a specified condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the first even number in the sequence, apply the The output is
last() function as follows:numbers.Last(Function(n) n Mod 2 = 0)numbers.Last(Function(n) n Mod 2 = 0)4.
The
LastOrDefault() function returns the last element, or a default value if no element satisfies the condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the first odd number in the sequence, apply the The output is
FirstOrDefault() function as follows:numbers.LastOrDefault(Function(n) n Mod 2 = 1)numbers.LastOrDefault(Function(n) n Mod 2 = 1)5.
The
Skip() function skips a specified number of elements in a sequence.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To skip the first two elements in the sequence, apply the The output is
Skip() function as follows:numbers.Skip(2).ToArray()numbers.Skip(2).ToArray(){3, 4, 5}.
The
SkipWhile() function skips elements until a condition is no longer satisfied.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To skip the numbers which are lower than 3, apply the The output is
SkipWhile() function as follows:numbers.SkipWhile(Function(n) n < 3).ToArray()numbers.SkipWhile(Function(n) n < 3).ToArray(){3, 4, 5}.
The
Take() function returns a specified number of elements from the start of a sequence.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the first three elements in the sequence, apply the The output is
Take() function as follows:numbers.Take(3).ToArray()numbers.Take(3).ToArray(){1, 2, 3}.
The
TakeWhile() returns elements until a condition is no longer satisfied.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To get the numbers which are lower than 4, apply the The output is
TakeWhile() function as follows:numbers.TakeWhile(Function(n) n < 4).ToArray()numbers.TakeWhile(Function(n) n < 4).ToArray(){1, 2, 3}.
The
Any() function returns true if any element in a sequence satisfies a specified condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To find out if at least one number in the sequence is even, apply the The output is
Any() function as follows:numbers.Any(Function(n) n Mod 2 = 0)numbers.Any(Function(n) n Mod 2 = 0)true.
The
All() returns true if all elements in a sequence satisfy a specified condition.
Assume you have a variable called
numbers defined as Integer() = {1, 2, 3, 4, 5}.
To find out if all the numbers in the sequence are positive, apply the The output is
All() function as follows:numbers.All(Function(n) n > 0)numbers.All(Function(n) n > 0)true.
The list function
AddItemToList() adds a new item to an existing list.
Assume you want to manipulate the records in an Edit Grid control with data from a process integration, using the Set Value rule. The item to set is
Processes.ALLDATATYPES.out_genericList.
To add an item to the generic list, assign it the following value:
AddItemToList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.NewItem)AddItemToList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.NewItem)The list function
DeleteItemFromList() deletes items from an existing list.
Assume you want to manipulate the records in an Edit Grid control with data from a process integration, using the Set Value rule. The item to set is
Processes.ALLDATATYPES.out_genericList.
To delete an item from the generic list, assign it the following value:
DeleteItemFromList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex)DeleteItemFromList(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex)The list function
UpdateListItemAtIndex() updates items in an existing list.
Assume you want to manipulate the records in an Edit Grid control with data from a process integration, using the Set Value rule. The item to set is
Processes.ALLDATATYPES.out_genericList.
To update an item in the generic list, assign it the following value:
UpdateListItemAtIndex(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex, MainPage.EditGrid.SelectedItem)UpdateListItemAtIndex(Processes.ALLDATATYPES.out_genericList, MainPage.EditGrid.RowIndex, MainPage.EditGrid.SelectedItem)- VB function: Where
- VB function: Select
- VB function: Aggregate
- VB function: Group By
- VB function: Order By
- VB function: Join
- VB function: First
- VB function: First Or Default
- VB function: Last
- VB function: Last Or Default
- VB function: Skip
- VB function: Skip While
- VB function: Take
- VB function: Take While
- VB function: Any
- VB function: All
- VB function: Add item to list
- VB function: Delete item from list
- VB function: Update list item at index