The WrapLinkList widget pulls unique cell values from a group of wraps that fulfill certain criteria. It is used to populate a dropdown list with all possible valid values to choose from, e.g. all railway cars in a particular depot with a pending error report.
A common WrapLink uses a unique key to return a single value from a single wrap. If you need a list of values from all the wraps that match a particular condition, use the WrapLinkList widget instead, and specify a non-unique key that matches more than one wrap.
Example: If you use a key that designates a particular depot for rolling stock, you may retrieve the identities of all the railway cars that belong to this depot and have one or more open error reports. Prefilling a dropdown widget with these identities makes it easy for the maintenance personnel to quickly select the railway car they are working on. Using a dropdown also eliminates the risk of typing errors in a free-text field.
You can use a Holder Cell to provide a dummy menu choice to test the wrap already in Excel. When the wrap is run on the server, WrapLinkList extracts live data from the cloud database and creates a dropdown menu with all the live candidates in the holder cell.
The WrapLinkList widget is a visual guide that helps you insert a wraplinklist() function into the current cell. If you want to link to a Wrap that doesn’t yet exist on the Wrapsite, you need to insert the =wraplinklist() function manually into the cell using the Function Reference section below. This is because the visual guide relies on the Wrapsite properties to provide a definition of the Wrap you want to link to, including its Unique Keys and the field you want to create the list from. Without this information, the guide cannot give you much help anyway.
If you already have a MyWraps report returning a list of choices, an alternative to WrapLinkList is to use the MyWraps link in a MyWraps2 function to have a list with item separators returned in a single cell of the dashboard Wrap. You can then use this list with a Dynamic Dropdown.
We encourage you to assign cell names to calculated cells, so that they get correct headings in MyWraps reports. A convenient MapToNames tool can save time by automatically using the field label as the cell name.
Select the source wrap from which you want to pull data. If you have a database background, you can think of this as selecting a table.
The first part of this section lets you specify all but one of the keys and values that together form the Unique Key that designates the wraps that you want to pull data from. To continue the database analogy, this key will select one or more rows in the source table. You must leave one key unselected – the resulting key must not be unique if it is to return values from more than one wrap.
As a developer, you may want to construct the key dynamically using runtime values from other cells in the wrap. You can insert cell references here or by editing the inserted wraplinklist() function call as described below.
The second part of the formula builder lets you select the “filter” cell in the source wraps that you want the WrapLinkList to retrieve (the column, if you think of the wrap as a table). After the call has been made, the returned values will be inserted as a dropdown menu in the cell where the =wraplinklist() function call resides, and in the holder cell, if there is one.
While you test the wrap in Excel, you can provide a test value in a special holder cell to verify that other formulas in the wrap return the correct results. When you upload the wrap, live data automatically replaces the test value in the holder cell. For a WrapLinkList widget, the holder cell contains the item selected from the dropdown list.
If you enable a holder cell for the widget, the cell immediately to the right of the WrapLinkList widget is chosen by default. You can change the location of the holder cell by clicking on the “pen” symbol and then selecting a different cell as the holder cell.
Holder cells sometimes contain information that you don’t want to show to the user of the wrap. In this case, tick this box to make the contents of the holder cell invisible in the wrap.
This is the value that the holder cell will contain during testing in Excel. When the wrap is running on the server, real values from the database are used, and the dummy value has no meaning. There are three possible types of values you can put here, depending on the situation:
The OADate format is easy to handle for Excel developers because it is the same as an ordinary Excel serial number, i.e. the standard decimal number that Excel uses for timestamps internally. The integer part counts the number of days and the decimal part tells the time of day. When you use an OADate in a holder cell, it must be formatted as a decimal number, not using a date or time format.
Read more about testing Wraps in Excel.
Wraps often link to each other. To provide the most recent information, linked wraps must be recalculated for every access to ensure that they in turn inherit the current values from their own linked wraps and return the most recent values to their caller.
Recalculation is normally instantaneous, but when a large number of wraps are affected by the same operation, e.g. a dashboard-style wrap that retrieves information from numerous other wraps, recalculating all the affected live wraps in a cascading fashion can have a noticeable effect on the wrap’s response time. Users must always wait for all the initiated recalculations to complete before the updated wrap appears on the screen.
In many cases, however, the information being gathered is historical. As an example, a dashboard of KPIs for the previous year, month, or week only reflects events in the past. For historical data, the recalculation of all the instances is unnecessary because the data never changes. It is good practice to freeze all wraps that no longer can change since it tells the system that they never again have to be recalculated.
Even with live wraps, the most recent changes can be irrelevant, which makes the recalculation unnecessary. You should open such wraps using the openmode=fast parameter in the link. With this option, all database operations will reuse the results from the most recent recalculation of each instance instead of recalculating it again, drastically reducing the response time when there are many links.
So, before any results are returned from a wrap:
The unique values in the source cell designated by the filter parameter are retrieved for all wraps matching the link and the unique key. The resulting list is copied into a dropdown menu appearing in the same cell as the WrapLinkList function. The dropdown menu is also created in the holder cell, if any.
If you test a WrapLinkList function within Excel, and a holder cell has been defined, the dummy list in the holder cell is returned instead of live data. If no holder cell has been assigned in the function call, the dropdown will not be populated.
If you haven’t specified a filter parameter, the dropdown will not be populated.
If the cell name in a filter parameter does not exist, the WrapLinkList displays a red “not available” icon. 
If a wrap has an empty or null value in the source cell designated by the filter parameter, the dropdown will contain choices that are empty strings or zeros.
If you link to a group of wraps using a unique key that does not match any existing wraps in the database, the dropdown will not be populated.
If the link points to a wrap that is not installed or where the unique key combination is invalid (does not resolve to a single wrap), a red “undefined” icon is displayed. 
If the link in the function call is empty, i.e. =WrapLinkList(“”), nothing is displayed. This may be useful if you want to use an IF() statement inside the WrapLinkList formula and return an empty link if the function shouldn’t be executed.
If there is no link in the function call, the WrapLinkList function returns an empty string.
Read more under Conditional request below.
A WrapLinkList is inherently dynamic and there is no guarantee that a previously selected and saved value is still eligible. As an example, a railway car may be included in a list for one particular mileage, but not when the next higher mileage is selected. ExcelWraps detects this and colors the cell background red to alert the user of the situation. To avoid locking the user out, the updated wrap can still be submitted also with this error.
When you develop a new version of a wrap, you may change a previously static dropdown list to a dynamic WrapLinkList. The static list may have been defined using Excel’s Data Validation, or using the static Dropdown or Dynamic Dropdown widgets. If an old wrap has a value that is not available in the new dynamic dropdown created with a WrapLinkList, this will be highlighted with a red border.
One of the purposes of a WrapLink is to construct a valid hyperlink to another wrap. This link is a standard Uniform Resource Locator (URL) that contains your WrapSite’s name, a folder path, the name of the wrap, the names of the fields forming the key, and the filter name.
A URL must conform to certain rules, of which the most important is that the following characters have special meaning: ! * ‘ ( ) ; : @ & = + $ , / ? # [ ] Some of these characters are allowed in the names for Excel files, worksheets and cells, but we strongly recommend that you never use any of the reserved characters.
If you have a very special need to use one or more of the reserved characters (aside from their reserved meaning), they must be encoded. The reserved character /, for example, if used in the “folder path” component of a URL, has the special meaning of being a delimiter between folder names (path segments). If / needs to be used in a folder name, then you must percent-encode it to %2F or %2f instead of using the raw /. You can use the EncodeURL() function in Excel 2013 or later to percent-encode any names that may contain reserved characters.
If a wrap is frozen, any dynamic data pulled into the wrap using WrapLinks, WrapLinkLists, WrapLinkAggregates or MyWraps2 will no longer be updated. A frozen wrap always reflects exactly the conditions when it was frozen.
WrapCreator does not prevent a wrap from linking to itself, or including itself in a linked aggregate or list. If you create a nested design like this, you should be aware that WrapLinks don’t always return the most current value. To maintain reasonable performance, linked data is cached and refreshed only in certain situations.
Example: Wrap A has a cell todaysdate that is a WrapLink to a cell in Wrap B which fetches the value from wrap C. The cell value in a Wrap C will not be updated until the Wrap is saved, say on the Monday. The new value will not reach and be reflected by Wrap B until it is opened, which may be on the Tuesday. The linked cell in Wrap A will not be updated until Wrap B has both been opened and saved with the new value it got from Wrap C, which may be on the Wednesday. Now imagine if Wrap A links to itself for a value. The same delay will occur, so the source value (that is linked to) will often be more current, and different, from the linked value – in the same Wrap.
The circumvention is simple, instead of using a WrapLink to fetch todaysdate from the same wrap, simply use a direct cell reference like =todaysdate in the target cell.
In WraplinkLists, the list returned by a nested call will not include a cell value that hasn’t previously been saved. Example: If you use a WraplinkList in a Wrap template to return all the car numbers for which there are instances of the Wrap, then create a new instance of the Wrap for car 7013, this car number will not appear in the WraplinkList for the 7012 Wrap until you save the 7013 wrap and then open the 7012 wrap.
In WraplinkAggregates, the aggregate returned by a nested call will be calculated using the most recent values in the database. Example: A WraplinkAggregate is calculated in wrap template A as a SUM of a cell in all A wraps. There are only three A wraps with the most recently saved values for the cell being 1, 2 and 3, respectively. The sum will be returned as 6, regardless of which of the three wraps you open. If you change the source value in the third wrap to 8, the aggregate will not be recalculated and the sum will not be affected until you save the third wrap with the new value. You then have to open either of the three wraps to have its aggregate refreshed to return 11.
Due to a design constraint, the WrapLink family of functions and MyWraps2 may not return the expected results for frozen wraps when placed in hidden cells. If you want to hide the result of a linking function, you should place it on a separate hidden sheet.
Before you create your first wrap, you must install the Wrap Package that you downloaded from your wrapsite so that WrapCreator has all the information it needs about your wrapsite and how it is set up. The Wrap Package synchronizes Excel to your wrapsite and should be updated periodically to give WrapCreator access to the most recent wrap and user definitions.
To delete a field, widget, wrap function or signature that has been stored at least once in the live production database is not a trivial task. The instructions below are only applicable during the initial development of a wrap, before it has ever been used in production. Read more about making changes to your wraps.
To remove a WrapLinkList widget:
In the example above, the following cell formula is inserted in the cell.
=@WrapLinkList("car?unit="&J6&"&filter=car")
You can edit the formula to use cell references instead of static values. If the wrap has the unit number in a named cell you can use the following formula:
=@WrapLinkList("car?unit=" & Unit_Num & "&filter=car")
=@WRAPLINKLIST("link")
link is a quoted text string that identifies the wrap you want to pull data from, provides the common key for the multiple wraps you are selecting, and what value you want to be returned from them. The unique retrieved values are used to create a dropdown menu in the cell where the WrapLinkList is located, and in the holder cell, if any.
The different values that are returned by the function call are described in detail in the Results section above.
The parameters for a link are specified in the query string. The query string is appended to the wrap name following a question mark. Within the query string, parameters are separated by ampersands. In the example above, the query string begins with a question mark and sends four parameters to the source wrap: mileage, car, end, and filter.
The link starts with the name of the wrap you want to link to, e.g. car in the example above.
The link must contain the Key that selects the group of wraps you want to pull data from. The Key is often assembled from several values, e.g. for a bogie overhaul you would need to identify the car type, what bogie on the car you refer to, and the mileage interval for the overhaul. You specify the components of the Key using the field names that the wrap is using for these values. In the example above, the Key is provided by the unit parameter.
The filter parameter returns a field value from the selected source wraps. The unique values in the field with this name are used to populate a dropdown menu displayed in the same cell that the =wraplinklist() formula occupies, and in the holder cell, if there is one.
Signatures contain information about the person who has signed, the company they work for, the date and time that the wrap was signed, the role required for signoff and the role required for unsigning. In the wraplinklist() formula, you can use some special keywords for signature cells (in the examples below, replace cell_name with your name for the signature cell). filter-sig-detail=cell_name This will provide all the details of the signature e.g. “John T. Doe, MoreVision Limited – Stainburn 09/12/2019 19:23 Sign(Operative) Unsign(Manager)”. filter-sig-summary=cell_name This provides summary info for the signature, e.g. “JTD 09/12/2019”. filter-sig-datetime=cell_name This provides the date and time of the signature, e.g. “09/12/2019 19:23”. filter-sig-date=cell_name This provides the date of the signature, e.g. “09/12/2019”. filter-sig-time=cell_name This provides the time of the signature, e.g. “19:23”.
You can only return the values of one field in a WrapLinkList, so the filter and filter-sig-xxx parameters are mutually exclusive.
The state of a Wrap at any time is Live or Frozen. A WrapLinkList can be restricted to live wraps only. If you specify state=live, the wrap will only select the wraps that have not been frozen.
Some live Wraps will be AwaitingSignature (waiting for the logged-in user to sign the wrap) or SignedByMe (when the signature has already been made). The state Any includes all Wraps.
=@WrapLinkList("car?unit=" & Unit_Num & "&filter=car&state=live")
WrapLinkList is a top-level function and cannot be nested inside another function like IF. If you want to make the function call only if a certain condition is True, you can place an IF statement around the link, and return an empty link to deactivate the function:
=WrapLinkList(IF(required_field="","","link"))
When a Wrap only provides historical information, e.g. as a dashboard, you should always consider appending &openmode=fast to the link to it. This greatly increases performance. Read more under Openmode=fast above.
You can use a Holder Cell to provide a dummy menu choice to test the wrap already in Excel. When the wrap is run on the server, WrapLinkList extracts live data from the cloud database and creates a dropdown menu with all the live candidates in the holder cell.
=HOLDER(cell_name, dummy_value, hidden, holder_item)
cell_name points to the WrapLinkList cell using its cell name.
dummy_value contains a value you want the cell to provide during testing in Excel – at runtime, real values from the server are used instead. The dummy value must have the same data type as the value that will later be returned by the server.
hidden if set to TRUE, makes the contents of the holder cell invisible in the wrap.
holder_item is always empty for WrapLinkLists.
=HOLDER(Unit_Num, 500, TRUE, "")