TextDropDownFields property

The text drop-down fields of this form screen as an array.

Accessing all text drop-down fields of a form screen through this property has many uses:

• Determining the text drop-down field with the longest value of all text drop-down fields of a form screen.
• Enabling a button only if all text drop-down fields of a form screen are valid.
• Deciding which background color to use based on whether the text drop-down fields of a form screen are valid.
• Collecting the labels and values of all text drop-down fields of a form screen as a text string, for use as the body of an email.
• Only allowing a user to move forward to the next screen if they have filled out all text drop-down fields of a form screen.

The following sections detail how these scenarios can be realized. Skip to the examples at the bottom for the concise version.

Determining the length of the longest text drop-down field value

This formula returns the length of the longest value of a text drop-down field:

The LEN function returns an array of the lengths of all the text drop-down field values, and MAX returns the largest such number.

The formula above can also be written as follows:

However, as the LEN function is looking for an array of text strings, and text drop-down fields return text strings through their Value properties, .Value,Value is inferred and does not need to be spelled out.

In fact, you can make the formula even shorter:

In the formula above, .Items.Value,Items,Value is inferred. In other words, the Items property is accessed, which includes not only fields, but also buttons and text boxes. As buttons and text boxes cannot return text strings, they are ignored by the LEN function, meaning that MAX(LEN(Screen1))MAX(LEN(Screen1)) returns the maximum length of all items that can return text strings, including text fields and text drop-down fields.

If you explicitly only want to include the values of text drop-down fields, and not values of text fields, be sure to write MAX(LEN(Screen1.TextDropDownFields))MAX(LEN(Screen1,TextDropDownFields)).

Determining the longest text drop-down field value

If you'd prefer to find not just the length of the longest text drop-down field value, but the actual value, use this formula:

The formula above uses the LET function to assign names to intermediate values. First, the fields to process, Screen1.TextDropDownFieldsScreen1,TextDropDownFields, are assigned the name Fields. Then, the length of the longest text drop-down field value is found, using the familiar MAX(LEN(Fields))MAX(LEN(Fields)) formula fragment and assigned the name MaxCount.

The third step assigns the name LongestTextDropDownFields to an array containing all text drop-down fields whose values are maximally long. There may be multiple such text drop-down fields.

In order to build this array, the FILTER function is used. It accepts the fields as its first parameter and, as its second parameter, LEN(Fields) = MaxCountLEN(Fields) = MaxCount is given. The second parameter constructs a logical array, which is FALSE for all elements that correspond to text drop-down fields whose values are not equal to the calculated maximum length and TRUE for those that pass the test. In effect, FILTER returns an array containing only those text drop-down fields whose values are maximally long.

Finally, the INDEX function returns the first text drop-down field from the resulting array.

(It is also possible to use the REDUCE function to solve this problem in one step. Its documentation includes an example that does just that.)

Enabling a button only if all text drop-down fields are valid

The Enabled property of a button determines if users can interact with the button. If a button should only be enabled if all text drop-down fields of Screen1 are considered valid, associate this formula with the Enabled property of the button:

Above, the Screen1.TextDropDownFields.ValidScreen1,TextDropDownFields,Valid formula returns an array of logical values (TRUE or FALSE), where TRUE indicates that a text drop-down field is valid and FALSE indicates that a text drop-down field is invalid. The AND function, when applied to this array, returns TRUE only if all array elements are TRUE. In effect, the button is only enabled if all text drop-down fields of the form screen are valid.

Making the background color red if a text drop-down field is invalid

The BackgroundColor property determines the background color of a screen and all screens that follow that have no explicit background color set. That means that if the background color is set for the first screen of an app, and no other screens have a background color set, the first screen determines the background color of the entire app.

We can make use of this knowledge to make the background of the entire app red, but only if at least one text drop-down field of the form screen Screen1 is invalid. This formula is associated with the BackgroundColor property of the first screen:

The formula fragment Screen1.TextDropDownFields.ValidScreen1,TextDropDownFields,Valid returns a logical array, where TRUE indicates that the corresponding text drop-down field is valid and FALSE indicates that the corresponding text field is invalid. Applying the NOT function to this array negates every element, meaning that TRUE indicates that a text drop-down field is invalid and FALSE indicates that a text drop-down field is valid. (The ! operator would have had the same effect.)

Then, the OR function is applied to this array. It returns FALSE only if all elements of the array are FALSE. In other words, it returns TRUE if one or several elements are TRUE, meaning that it returns TRUE if one or several text drop-down fields are invalid.

Finally, the IF function is used to return the color red if one or several text drop-down fields are invalid. Otherwise, IF returns a blank value, which has no effect on the background color. The net effect is that the background color of the app is made red if one or several text drop-down fields of Screen1 are invalid.

Including all text drop-down field values of a form screen in an email

The Body property of email report buttons allows the body of an email to be set through a formula. While email report buttons have built-in support for including field values, through the IncludedFields property, building a text string manually to include in the email body allows us more flexibility.

Consider this formula, which should be associated with the Body property of an email report button:

Above, the formula fragment Screen1.TextDropDownFields.LabelScreen1,TextDropDownFields,Label returns a text array, made up of the labels of the text drop-down fields of Screen1. The formula fragment Screen1.TextDropDownFields.ValueScreen1,TextDropDownFields,Value also returns an array, this time made up of the values of the text drop-down fields. Using &, the labels are joined together with the values, separated by a colon.

The resulting text array, where every element consists of a label, followed by a colon and a value, is converted into a single text string using the TEXTJOIN function. Its first parameter, NEWLINE()NEWLINE(), ensures that the array elements are separated from one another using line breaks.

Requiring all text drop-down fields of a form screen to be filled out

The NextScreenAvailable property of form screens determines if users are allowed to move forward to the next screen. If a user should only be allowed to move forward once all text drop-down fields of a form screen have been filled out, associate this formula with the NextScreenAvailable property of the form screen:

The ISDEFINED function returns a logical array when its sole parameter is an array. TRUE elements in the array indicate that the corresponding text drop-down fields have defined values, that is, have been filled out, and FALSE elements indicate that the corresponding text drop-down fields have not been filled out.

Finally, the AND function returns TRUE only if all elements of the array are TRUE, otherwise it returns FALSE. The net effect is that AND returns TRUE only if all text drop-down fields of Screen1 have been filled out, prompting the NextScreenAvailable property to only allow users to proceed once all text drop-down fields have defined values.

Ranges versus this property

If the form screen Screen1 only consists of the text drop-down fields Field1, Field2 and Field3, these formulas are equivalent:

The second formula uses a range to create an array consisting of Field1, Field3 and all items that appear between them, which in this case is only Field2.

The chief advantage of the TextDropDownFields property, compared to a range, is that there is no need to update formulas when additional text fields are added to a form screen. If Field4 were to be added to the form screen, the Field1:Field3Field1:Field3 range would have to be changed to Field1:Field4Field1:Field4 everywhere it is used.

By contrast, Screen1.TextDropDownFieldsScreen1,TextDropDownFields automatically includes Field4, and any other text drop-down fields that are added.

Filtering text drop-down fields

If you want to process only a subset of the text drop-down fields returned from this property, use the FILTER function. It can base its decision on which text drop-down fields to return on the property values of the text drop-down fields.

This formula only returns visible text drop-down fields:

Crucially, you can also filter on the names of the text drop-down fields, using standard text functions. This formula only returns text drop-down fields whose names include the text string "Required":

If you use a deliberate naming strategy for your text drop-down fields, you can use FILTER in conjunction with this property to ensure that you only process a specific subset of text drop-down fields.

Related properties

Use the TextDropDownFields property of a form group to access all text drop-down fields of said form group and the TextDropDownFields property of the app object to access all text drop-down fields of the entire app.

The Fields property returns all fields of a form screen, not just text drop-down fields. The Items property returns all items of a form screen, including fields, buttons, text boxes and named values. Use NumberFields, TextFields, SwitchFields, DateTimeFields and NumberDropDownFields to access other kinds of fields.

Examples