Grids allow us to display data in a tabular format (AKA a table). A database table has a set of fields that, when populated, become the records. A grid displays fields as columns and records as rows. The read-only grid understands the relationship between columns and rows, and is designed to handle your data in intelligent ways.
In this tutorial, you'll learn all the major features and functions of the read-only grid by creating a grid with selection pattern in Design Mode (the best way).
We've been asked to create a grid list that displays a complete list of all employees in the company. From the grid, we should be able to select any number of employees to be entered into a raffle and configure a secondary display zone that populates a list of selected employees by their first and last name. We've also been asked to prevent the selection of employees in the Sales department (since they're already drowning in additional compensation), but allow them to still show up in the grid list.
Tip: The interface you'll create is a variation of the Grid with Selection pattern. Component patterns are a great way to get started quickly, or learn from expert designs.
Learn how to create a read-only grid with the most common configurations in about 15 minutes. After completing this tutorial, you will know how to:
This tutorial requires basic familiarity with the Appian platform. If you are brand new to Appian, head over to Appian Academy Online and explore the many, free courses available.
Before beginning this tutorial, you must first:
EMPLOYEE_ENTITY), set in your environment. If you do not have this example data, you must create it by completing the Use the Write to Data Store Entity Smart Service Function on an Interface recipe.
Note: You can substitute your own manual data but you will not have the same tutorial experience and the results shown in this walk through will not evaluate in your environment.
In this tutorial, we'll be working with the following design objects and components:
First, we're going to set up our grid in Design Mode by dragging the read-only grid component from the Components Palette.
AT_raffleGridGrid for selecting employees for the raffle.AT ExamplesAfter dragging the grid onto your interface, you can add data from the COMPONENT CONFIGURATION panel on the right.
EMPLOYEE_ENTITY.The query editor makes creating queries easy.
For our query, we only need the following fields:
idfirstNamelastNamedepartmentstartDateHowever, in the Fields section, you can see that all fields are selected by default.
To remove the fields you don't need from the Query Results Preview:
title and phoneNumber columns, and click REMOVE.Click GENERATE QUERY.
Your grid is now populated with the employee data from the query.
If you're just reading this tutorial, and you see the image above and think, "Wait, that was too easy. I must have missed a bunch of steps somewhere." You can relax; you didn't miss anything. When you use the query editor from the context of a grid, Appian takes the query results and automatically populates the grid columns, makes them sortable, and takes a good guess as to what your column names might be. In addition, when Appian detects a column with numbers or dates, it aligns the field data to the right for you.
You can configure paging and sorting for the query, but the grid handles both natively. This allows you to change these settings from the COMPONENT CONFIGURATION panel.
5 in Rows to Display Per Page.Note that when you add an initial sorts parameter in Design Mode, the following error message will display. The error will resolve when you enter a field name:
"Interface Definition: Expression evaluation error at function a!gridField [line 2]: Expression evaluation error at function a!queryEntity [line 5]: Cannot sort by a blank field."
lastName.Appian automatically passes the field data returned from the query into their respective columns. The display value of every column is set with the function variable, fv!row. This variable contains all the data for the entire row. For example, in the First Name column, the display value is fv!row.firstName.
In this section, we will remove the ID column and change the format of the Department column to italics and conditionally change the color of the text.
Since we don't need to see the employee's ID, let's remove it.
Now, let's format the Department column by changing the text style.
Since we don't want anyone from the Sales department entered into the raffle, let's remind the user by changing the color of "Sales" in that column.
if(fv!row.department="Sales", "SECONDARY", null)Click OK.
Now when the row evaluates, if the Department in that row (fv!row.department) is Sales, the color will be set to "SECONDARY" for the row; otherwise it'll be null (the default).
When grids have selection and paging, it's good UX practice to provide a secondary display so the user can see the totality of their selection no matter what page they're on.
If you're familiar with interface design, you can follow the higher-level steps below to add a display zone. If you're still somewhat new to interface design in Appian, skip to these directions.
WIDE.user-circle).First Last).Drag a COLUMNS component from the palette to just below the grid.
Delete one of the columns by clicking on the Delete column icon ().
Hover over the Read-Only Grid selector until the component hierarchy displays, then click Column Layout.
Now that the column is selected, let's increase the width.
Now, let's add a display field
user-circle into the search box and select this icon (), and click INSERT.In the editor, after the icon, enter ` First Last`.
And this is where we're going to leave it for now:
To set up grid selection, you need to create a local variable to save the selection value into. In our case, we also need to pass the selected row's data to a local variable so we can display the selected employees in the display zone. To accomplish this, we're going to add two local variables: (1) local!selection for the grid's current selection, and (2) local!selectedEmployees for the row data of those selections.
To add these local variables, you need to switch to Expression Mode.
Wrap the expression with the a!localVariables() function, and add two local variables:
local!selectionlocal!selectedEmployees1
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a!localVariables(
local!selection,
local!selectedEmployees,
{
a!columnsLayout(
columns: {
a!columnLayout(
contents: {
a!gridField(
label: "Read-only Grid",
labelPosition: "ABOVE",
data: a!queryEntity(
entity: cons!EMPLOYEE_ENTITY,
query: a!query(
selection: a!querySelection(
columns: {
a!queryColumn(
field: "id"
),
a!queryColumn(
field: "firstName"
),
a!queryColumn(
field: "lastName"
),
a!queryColumn(
field: "department"
),
a!queryColumn(
field: "startDate"
)
}
),
pagingInfo: fv!pagingInfo
),
fetchTotalCount: true
),
columns: {
a!gridColumn(
label: "First Name",
sortField: "firstName",
value: fv!row.firstName
),
a!gridColumn(
label: "Last Name",
sortField: "lastName",
value: fv!row.lastName
),
a!gridColumn(
label: "Department",
sortField: "department",
value: a!richTextDisplayField(
value: {
a!richTextItem(
text: {fv!row.department},
color: if(fv!row.department="Sales", "SECONDARY", null),
style: {
"EMPHASIS"
}
)
}
)
),
a!gridColumn(
label: "Start Date",
sortField: "startDate",
value: fv!row.startDate,
align: "END"
)
},
pageSize: 5,
initialSorts: {
a!sortInfo(
field: "lastName",
ascending: true
)
},
validations: {}
)
},
width: "WIDE"
),
a!columnLayout(
contents: {
a!richTextDisplayField(
label: "Rich Text",
labelPosition: "COLLAPSED",
value: {
a!richTextIcon(
icon: "user-circle"
),
" First Last"
}
)
}
)
}
)
}
)
Don't forget to add the final close parenthesis on line 100.
Now, switch back to DESIGN MODE.
In the expression editor, enter this expression:
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{
local!selection,
/* This save adds the full rows of data for items selected in the most recent user interaction to local!selectedEmployees. */
a!save(local!selectedEmployees, append(local!selectedEmployees, fv!selectedRows)),
/* This save removes the full rows of data for items deselected in the most recent user interaction to local!selectedEmployees. */
a!save(local!selectedEmployees, difference(local!selectedEmployees, fv!deselectedRows))
}
You can now persist your selection. Try it out by selecting and deselecting rows. The selection index is saved to local!selection, and the row data for those selections is saved to local!selectedEmployees; you can't see that yet, but we'll set that up in the next section.
Tip: The grid is actually smart enough to use a single selection variable for both the selection index and the row data when you embed a query that returns a primary key, as the query will create a datasubset with the primary key as the identifiers. You can test it out by setting the Selection Value to local!selectedEmployees.id. If you only pass the data, the grid won't know which field is the primary key, so you'll need to create a second variable for the selection index; we show the two-variable method in this tutorial because it works in both cases.
It's time to configure the second column of our interface to show the employee names of the selected rows. With the components we want already setup, we're going to wrap them in a looping function (a!forEach()) to reuse them for every employee in local!selectedEmployees.
Hover over Display Value until the () Edit as Expression icon appears, then click it. You will see the following expression in the editor:
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{
a!richTextIcon(
icon: "user-circle"
),
" First Last"
}
Replace that expression with this one:
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a!forEach(
items: local!selectedEmployees,
expression: {
a!richTextIcon(
icon: "user-circle"
),
" " & fv!item.firstName & " " & fv!item.lastName&char(10)
}
)
Select Scott Bailey, Laura Bryant, and Janet Coleman in the grid to see that name appear on the right.
Changing the color of "Sales" isn't enough; to prevent users from selecting anyone in the Sales department, we're going to tell the grid to disable selection for rows when the department in that row is Sales.
Note: Be sure to unselect the employee records you selected in Populate display section before proceeding with the steps in this section.
fv!row.department="Sales"Now employees in Sales can't even be selected from the grid. Try it out for yourself.
Now that you've had a good look at your grid, you realize not everyone will be interested in seeing those employees in Sales who aren't eligible for the raffle. So, we're going to add an option to hide those rows with a checkbox. For this, we're going to use the method described in the Configure a Boolean Checkbox pattern.
Before we create the checkbox, let's first create a local variable to store the checkbox value, and set a default value on load.
Insert another local variable (local!showIneligible: true) on line 4.
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a!localVariables(
local!selection,
local!selectedEmployees,
local!showIneligible: true,
{
Now that we have the local variable, we're ready to set up the checkbox to have only one option, and for that option to toggle true and null in the variable to act as a switch for the filter we will create in the next section.
Show ineligible employees1) with: trueif(local!showIneligible, true, null)Enter this expression:
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a!save(
local!showIneligible,
if(
isnull(save!value),
false,
true
)
)
Now the checkbox is all set up, let's connect a query filter to it.
We're going to add a simple filter to the query to exclude employees in the Sales department. This filter exclusion will only run when the checkbox variable (local!showIneligible) is false.
Sales.not(local!showIneligible)Now you can toggle the checkbox on and off to view or hide the Sales rows.
Now that it's all working, let's wrap up:
Employee Directory.Selected Employees.
That's it!
We know that was pretty easy, but you should feel proud anyway.
What you do next, is up to you.
Learn more about the Read-Only Grid, and find more patterns and examples here.
Grid Tutorial
