Mastering Dynamic Text: Advanced String Formatting in Dexterity Scrolling Windows (Dynamics GP)

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Working with data within user interfaces often requires flexible display options. In the realm of Microsoft Dynamics GP development using Dexterity, controlling how data, particularly text and numbers presented as strings, appears to the end-user is a fundamental task. Dexterity provides mechanisms to format strings dynamically based on specific conditions or linked data points, enhancing the usability and clarity of application windows. This capability is crucial for displaying information consistently and according to business rules.

One of the built-in features in Dexterity for handling dynamic string formatting involves associating multiple FormatString properties with a single string field. This allows developers to define different presentation styles for the same data field. To switch between these defined formats, Dexterity utilizes an integer field linked to the string field through the Link Format Selector tool, accessible during the window layout design phase. By changing the integer value in the linked field, the corresponding format from the list of FormatString properties is automatically applied to the string field, offering a straightforward way to achieve dynamic formatting on standard window fields.

While this linked format selection mechanism works seamlessly for string fields placed directly on a window, a notable limitation arises when attempting to apply this same technique within a scrolling window. Scrolling windows are essential components in Dynamics GP interfaces, used extensively to display lists or line-item details where the number of entries can exceed the visible area of the window. Unfortunately, the direct use of the Link Format Selector with string fields and their linked integer counterparts inside a scrolling window does not function as expected. This is a known issue that developers encounter when trying to implement dynamic text formatting within these common interface elements, necessitating alternative approaches to achieve the desired presentation logic.

Addressing the Challenge in Scrolling Windows¶

The inability to leverage the standard Link Format Selector feature within scrolling windows presents a specific development challenge. Developers frequently need to display data within scrolling lists using different formats depending on other data points in the same row. For instance, displaying a quantity with varying decimal places, showing a status code with different prefixes, or formatting a number field with conditional symbols might be required based on other data in the scrolling window line. Without a direct built-in mechanism, a custom solution is necessary to replicate this dynamic formatting behavior.

Fortunately, a robust workaround exists to effectively apply dynamic string formatting within Dexterity scrolling windows. This method involves manually managing the formatting process through Dexterity scripting and the use of auxiliary fields and messages. The core idea is to intercept the data before it’s displayed in the scrolling window and apply the desired format programmatically, bypassing the non-functional Link Format Selector feature in this context. This approach, while requiring a bit more manual coding than the ideal built-in feature, is highly effective and provides granular control over the formatting process for each row displayed in the scrolling window.

The workaround detailed here leverages Dexterity’s capabilities for string manipulation, message handling, and script execution within the scrolling window’s lifecycle. By following a structured set of steps, developers can implement dynamic text formatting that is visually indistinguishable from the behavior achieved by the standard Link Format Selector tool on non-scrolling window fields. This ensures that scrolling windows in Dynamics GP can still display data in a dynamically formatted manner, maintaining a professional and informative user interface despite the platform’s specific technical limitation.

Implementing the Workaround: Step-by-Step Guide¶

Implementing the custom dynamic formatting for scrolling windows involves several distinct steps, requiring careful planning and Dexterity scripting. Each step contributes to simulating the desired behavior by using alternative Dexterity features. Let’s break down the process:

Step 1: Create a Local String Field for Display¶

The first step is to create a new local string field within the Dexterity form definition. This new field will serve as the visual placeholder in the scrolling window where the dynamically formatted text will be displayed. It’s crucial to ensure that the keyable length of this local string field is sufficient to accommodate the longest possible formatted string, regardless of which format is applied. If the field is too short, the formatted text will be truncated, defeating the purpose of applying the format. This local field effectively acts as a ‘dummy’ or ‘display’ field that we will populate with the correctly formatted data.

This local string field will reside directly within the definition of the scrolling window layout. Unlike the original data field which might be bound directly to a table column, this local field is initially unbound to any persistent data source. Its content will be programmatically controlled by our custom script. Giving it a clear name (e.g., ‘(L) Dummy String’) in the Dexterity form structure helps in identifying its purpose within the window definition and subsequent scripting.

Step 2: Hide the Original String Field¶

Once the new local string field is placed in the scrolling window layout, the original string field that contains the raw, unformatted data needs to be hidden. This prevents the user from seeing two versions of the same data (one unformatted, one formatted) in the same scrolling window line. Hiding the original field ensures that the user interface remains clean and presents only the final, desired formatted output via the new local string field.

Hiding a field in Dexterity can be achieved by setting its Visible property to False or by simply overlaying it completely with the new local field during the layout design. The key is that the original field must still be accessible programmatically in scripts, as we will need to read its raw value to apply the formatting. The local field acts as the user’s window into the data contained in the original, now hidden, field. This separation of data storage (original field) and data presentation (local field) is fundamental to this workaround.

Step 3: Utilize Messages for Format Definitions¶

Instead of relying on the FormatString property list associated with the original field (which doesn’t work correctly in scrolling windows via the Link Format Selector), we will store our format definitions as Dexterity messages. Dexterity’s message system is typically used for storing user-facing text, prompts, and error messages, allowing for easy localization. However, it can also be repurposed to store formatting strings or patterns.

Create a series of new messages with unique IDs, conventionally starting with IDs greater than 22,000 in Dexterity customizations to avoid conflicts with standard Dynamics GP messages. Each message should contain one of the desired format strings. The order in which you define these messages is important because the integer field linked to the original string field (if it existed) would have corresponded to the index in the FormatString list. In our workaround, this integer field’s value will now correspond to an offset from a base message ID. For example, if your base message ID is 22200, and you have formats in messages 22201, 22202, and 22203, an integer value of 1 would indicate using message 22201 (Base + 1), 2 would indicate 22202 (Base + 2), and so on. Each message’s text content will be the actual format string (e.g., “XXX-XX-XXXX” or “$.XX”).

Step 4: Develop a Custom Formatting Function (Format_String)¶

The core logic of this workaround is encapsulated in a Dexterity function that takes the raw string data and the desired format string as input and returns the formatted string. This function mimics the behavior of how Dexterity’s built-in formatting would apply a pattern. The provided code snippet for the Format_String function serves this purpose. Let’s examine its components:

function returns string OUT_String;
in string IN_String;
in string IN_Format;

local integer i, j;
local string l_string;

clear l_string, j;
for i = 1 to length(IN_Format) do
    if substring(IN_Format,i,1) = CH_X then
        increment j;
        l_string = l_string + substring(IN_String,j,1);
    else
        l_string = l_string + substring(IN_Format,i,1);
    end if;
end for;
OUT_String = l_string;

This function, named Format_String, accepts two input parameters: IN_String (the raw data string to be formatted) and IN_Format (the format string pattern, like “XXX-XX-XXXX”). It returns a single string, OUT_String, which is the result after applying the format.

Inside the function:
- i and j are local integer variables used as counters. i iterates through the format string (IN_Format), while j tracks the position in the input string (IN_String).
- l_string is a local string variable used to build the formatted output incrementally.
- clear l_string, j; initializes l_string to empty and j to zero.
- The for loop iterates through each character of the IN_Format string.
- substring(IN_Format,i,1) gets the character at the current position i in the format string.
- CH_X is a Dexterity constant representing the character ‘X’, which is conventionally used as a placeholder in format strings to indicate where a character from the input string should be placed.
- If the current character in IN_Format is ‘X’ (= CH_X), it means a character from the input string should go here. increment j; advances the counter for the input string, and l_string = l_string + substring(IN_String,j,1); appends the next character from IN_String to the l_string.
- If the current character in IN_Format is not ‘X’, it’s considered a literal character (like ‘-‘, ‘$’, ‘.’, ‘(‘, ‘)’, etc.) that should be part of the output format. l_string = l_string + substring(IN_Format,i,1); appends this literal character to l_string.
- After iterating through the entire format string, OUT_String = l_string; assigns the constructed formatted string to the return variable.

This function provides a flexible way to apply various format masks defined using ‘X’ as a placeholder. For example, applying the format “XXX-XX-XXXX” to the string “123456789” would result in “123-45-6789”.

Step 5: Populate the Local Field in the Scrolling Window Fill Script¶

The formatting logic needs to be executed when the scrolling window lines are populated. The ideal place for this is the Scrolling Window Fill script. This script runs for each row as Dexterity retrieves data to display in the scrolling window. Within this script, you will call the custom Format_String function to format the data for the current row and assign the result to the local string field you created in Step 1.

The script line would look something like this:

'(L) Dummy String' of window Scrolling_Window = \
Format_String('String' from table Table, getmsg(Base + 'Format' from table Table));

Let’s break down this script line:
- '(L) Dummy String' of window Scrolling_Window: This refers to the local string field you placed in the scrolling window layout. This is where the formatted output will be placed for the current row.
- Format_String(...): This is the call to your custom function.
- 'String' from table Table: This represents the original unformatted string field, referenced from the table buffer. This is a critical point. You must use the field from the table buffer (from table Table) and not the window field (of window Scrolling_Window) here. The reason is that the window fields are populated by Dexterity after the Scrolling Window Fill script has finished executing for a given row. At the time the fill script runs, the window fields might not yet contain the data for the current row being processed, but the table buffer does.
- getmsg(Base + 'Format' from table Table): This retrieves the format string from the Dexterity message system. Base would be an integer variable or constant holding your base message ID (e.g., 22200). 'Format' from table Table represents the integer field in the table buffer that determines which format message to use for this row. This field holds the value (e.g., 1, 2, 3) that corresponds to the offset from the base message ID. getmsg() retrieves the text of the message corresponding to the calculated ID (Base + offset). This text is the format string pattern passed to the Format_String function.

This single line of code within the Scrolling Window Fill script, executed for every row, dynamically calculates the correct format message ID based on the integer field in the table buffer, retrieves the format string pattern from that message, passes the raw string data from the table buffer and the retrieved pattern to the Format_String function, and finally places the formatted result into the visible local string field in the scrolling window row.

Considerations for Editable Fields¶

The workaround described above focuses on displaying formatted data. If the string field within the scrolling window needs to be editable by the user, additional steps are required to handle the formatting during the editing process. When a user edits the field, they will be interacting with the local string field that contains the formatted text. If they type data that doesn’t match the format, or if the underlying data needs to be stored unformatted, you need to strip the formatting before saving and re-apply it after editing.

This can be handled using the field’s PRE and POST scripts:
- PRE Script: When the user tabs into the local string field (or it receives focus for editing), the PRE script fires. Here, you would take the formatted text currently in the local field, remove the literal formatting characters (like dashes, spaces, parentheses, etc.) to get the raw data, and potentially temporarily store this raw data in another variable or the original hidden field. Some developers might temporarily change the field’s content to the raw data for easier editing, or simply remember the raw value derived from the formatted string.
- POST Script: When the user tabs out of the local string field (or saves the record), the POST script fires. Here, you would take the text entered by the user into the local field, potentially strip any literal characters they might have typed, validate it if necessary, and then apply the correct format based on the linked integer field (or re-calculate the format index if the input data affects it). You would then use your Format_String function again to format the user’s input and put the result back into the local string field for display. The raw, unformatted data would be saved to the underlying table field.

This process is analogous to how date fields often work in user interfaces, where the displayed format might be MM/DD/YYYY, but the underlying stored value is a date data type. The system handles the conversion between the displayed formatted string and the internal data representation during editing. Implementing PRE/POST scripts for an editable dynamically formatted string field provides a similar user experience, ensuring that the data is displayed correctly according to the chosen format while allowing users to edit the underlying data effectively.

Illustrative Diagram¶

To better visualize the data flow and component interaction in this workaround, consider the following simplified diagram:

```mermaid
graph LR
A[Table Buffer Data] → B{Scrolling Window Fill Script};
C[Linked Integer Field
(from Table Buffer)] → B;
D[Messages (Base + Offset)
containing Format Strings] → B;
B → E{Format_String Function};
E → F[Local String Field
(in Scrolling Window)];
F → G[User Interface Display];

%% If field is editable
G -- User Edit --> H{Local Field PRE Script};
H -- Strip Format --> I[Raw Data (Temporary)];
I -- User Input --> G; %% User interacts with formatted field
G -- User Tab Out --> J{Local Field POST Script};
J -- Get User Input<br>+ Determine Format --> K{Format_String Function};
K --> F; %% Update displayed formatted value
K -- Save --> A; %% Update Table Buffer Data (raw)

```

This diagram illustrates how the data from the table buffer and the format index are processed in the fill script, routed through the custom function, and displayed in the local field. It also conceptually shows how editing would involve PRE/POST scripts to manage the transition between formatted display and underlying raw data handling.

Benefits and Considerations¶

The primary benefit of this workaround is that it allows developers to implement complex, dynamic string formatting within the scrolling windows of Dynamics GP applications built with Dexterity, overcoming a known platform limitation. It provides granular control over how each row’s data is displayed. Using Dexterity messages to store format strings also centralizes these definitions, making them easier to manage and potentially localize in the future.

However, this approach does add complexity compared to the ideal built-in feature. It requires manual coding of the formatting function and careful implementation in the Scrolling Window Fill script. For editable fields, the PRE/POST script logic further increases the development effort. Performance could also be a consideration for very large scrolling windows, as the formatting function is called for every row, although Dexterity’s speed typically mitigates this concern for standard scenarios. Developers must also ensure the base message ID and offset logic are correctly maintained and that the local string field is sufficiently long.

Despite the added complexity, this method is a proven and effective technique within the Dexterity development community for achieving advanced text display requirements in scrolling windows, ensuring that Dynamics GP applications can present information clearly and dynamically according to business logic.

Conclusion¶

Mastering dynamic text formatting, especially within crucial interface elements like scrolling windows, is vital for creating professional and user-friendly applications in Microsoft Dynamics GP using Dexterity. While a direct built-in feature has limitations in this specific context, the described workaround offers a powerful and flexible alternative. By creating a dedicated local display field, leveraging Dexterity messages for format patterns, implementing a custom formatting function, and carefully populating the field in the scrolling window’s fill script, developers can effectively simulate dynamic formatting behavior. Incorporating PRE/POST scripts further extends this capability to editable fields, providing a comprehensive solution. This technique underscores the adaptability of the Dexterity development environment, allowing developers to overcome platform-specific challenges and deliver sophisticated user interfaces.

Have you encountered similar challenges with dynamic formatting in Dexterity scrolling windows? How have you approached solving them? Share your experiences and insights in the comments below!