Pass the Microsoft Certified: Dynamics 365 Business Central Developer Associate MB-820 Questions and answers with ExamsMirror

In Business Central development using AL (the language for Business Central extensions), the use of access modifiers defines how variables and procedures are accessed within and outside of an object or codeunit.

Access Modifiers in AL:

Public: A public variable can be accessed from any object or codeunit within the same module or extension.

Protected: This restricts access to the current object and objects that inherit from the current object. However, in AL (at least in versions used for Business Central), the Protected access modifier is used with methods but not variables.

Internal: This modifier restricts the visibility to the current extension. This means that variables or methods declared as internal can only be accessed from within the same extension. This is appropriate when you want to provide functionality that is shared within the extension but not exposed externally.

Local: This restricts the variable or method to the current object or method where it is declared. It cannot be accessed from anywhere else, even within the same extension.

Scenario Justification:

In the scenario for Contoso, Ltd., IssueTotal is a global variable in the ISSUE BASE extension, and the ISSUE EXT extension needs to access it. Therefore, the variable cannot be declared as Local, because this would restrict access to just the current object (or method).

Using Public would expose the variable outside of the extension, which is unnecessary because you only want other parts of the extension (specifically the ISSUE EXT extension) to have access.

The best choice in this case is Internal because it restricts access to the variable to within the same extension, which includes the base extension and any dependent extensions like ISSUE EXT. It strikes the right balance between visibility and encapsulation.

Microsoft Dynamics 365 Business Central Developer References:

Access Modifiers in AL: Microsoft's documentation on AL provides the details on access modifiers, where it is specified that internal variables can be accessed within the extension, and the public variable is accessible across all extensions【source: Microsoft Learn on AL Programming】.

Best Practices for AL Development: Business Central development best practices suggest keeping variables internal unless they need to be accessed outside of the current extension【source: Microsoft Learn on AL development guidelines】.

In the context of Microsoft Dynamics 365 Business Central, an extension may not appear in the tenant for several reasons, particularly after an upgrade to a new major version.

Option A suggests that the extension was published as a DEV extension, which typically would not cause it to disappear after an upgrade because DEV extensions are intended for development and testing within sandbox environments.

Option B indicates that the extension was not compatible with the new version within 60 days of the first notification. This is a likely reason because Microsoft enforces compatibility rules, and extensions that are not made compatible within the specified timeframe might be removed or disabled.

Option C refers to the extension being published as a PTE (Per-Tenant Extension) and mentions the Platform parameter not being updated. This could cause issues, but not specifically the disappearance of the extension after an upgrade.

Option D expands on Option C by adding that both the Platform and Runtime parameters were not updated in the application file. This is a critical aspect because if these parameters are not correctly set to indicate compatibility with the new version of Business Central, the extension could be disabled or removed.

Option E is similar to Option B but mentions a 90-day period. This option does not align with standard Business Central practices for version compatibility requirements.

Therefore, the two possible reasons for the disappearance of the extension in the tenant after an upgrade are that the extension was not compatible with the new version within the required timeframe (Option B) and that the extension was published as a PTE without the Platform and Runtime parameters being updated (Option D).

Code Segment Analysis:

The AL code is trying to read JSON data from a response and process it to extract subcontracting order numbers. It uses JsonToken, JsonObject, and JsonArray to work with the JSON data.

JToken.ReadFrom(Data): This line reads the incoming JSON data and converts it into a token. It processes the full JSON body so you can start working with it.

JToken.SelectToken("results"): This line selects the part of the JSON containing the results array. The key "results" is where the JSON response data is expected to be found.

JsonArray: Once the results are extracted, they are stored as an array, and each element in the array (which is expected to contain subcontracting order numbers) is processed.

SubcontractingOrderNo: The extracted order_no from the JSON is stored in this variable.

Breakdown of Steps:

JToken.ReadFrom(Data): This step reads the entire JSON response.

JToken.SelectToken("results"): This step selects the results array from the JSON response.

JArray.AsArray(): This step converts the selected results token into a JSON array that can be iterated over.

GetValueAsText(JToken, 'order_no'): This step retrieves the order_no from each element in the array.

Correct Code Completion:

JToken.ReadFrom(Data): This is the correct method to read the incoming JSON response, as it will convert the string into a JsonToken that can be further processed.

JToken.SelectToken("results"): This is the correct method to extract the results array from the token. This method looks for the key "results" in the JSON and retrieves the relevant array.

Final Code Segment:

al

Copy code

procedure ReadJsonData(Data: text)

var

JToken: JsonToken;

JObject: JsonObject;

JArray: JsonArray;

SubcontractingOrderNo: Code[20];

begin

if Data = '' then

exit;

JToken := JToken.ReadFrom(Data); // Step 1: Read the JSON response data.

JToken := JToken.SelectToken('results'); // Step 2: Select the "results" array.

JArray := JToken.AsArray(); // Convert the token into a JSON array.

foreach JToken in JArray do begin

SubcontractingOrderNo := GetValueAsText(JToken, 'order_no'); // Retrieve the order number.

end;

end;

JToken.ReadFrom(Data): This reads the raw JSON data string and converts it into a JSON token that can be processed.

JToken.SelectToken("results"): This extracts the results array from the JSON data.

JArray.AsArray(): Converts the token into an array so we can iterate over it.

GetValueAsText(JToken, 'order_no'): Extracts the order_no value from each item in the array.

To correctly write the code to call the subcontractor's REST API, you would need to set the Authorization header with the base64 encoded username and password for basic authentication. The code segment indicates the use of the Base64Convert codeunit to convert the username and password to base64 format, which is then prefixed with "Basic " to form the proper Authorization header value.

The correct method to add the Authorization header to the RequestHeaders would be:

RequestHeaders.Add('Authorization', 'Basic ' + Base64Convert.ToBase64(Username + ':' + Password));

And the correct method to set the httpContent with the body of the request would be:

httpContent.WriteFrom(Body);

These are the necessary steps to form a well-structured HTTP request for basic authentication and to include the body of the request in the API call.

In Microsoft Dynamics 365 Business Central, when configuring snapshot debugging, it is crucial that the parameters in the configuration file are correctly set. From the options provided, the issue with the debugger not starting correctly is most likely due to an incorrect "userId" parameter.

Option A is the cause of the problem. The "userId" parameter must be the GUID of the user, not the username. The snapshot debugger needs the exact GUID to attach to the right session for debugging.

Option B is incorrect because "breakOnNext" set to "WebClient" is a valid setting. This tells the debugger to break on the next client action in the web client, which is a typical scenario.

Option C is not the cause of the problem. The "userId" parameter is meant to specify which user session to debug, and this works in conjunction with the "breakOnNext" parameter.

Option D is incorrect as the "executionContext" parameter does not need to be set to "Debug" for snapshot debugging to work. "DebugAndProfile" is a valid value for the "executionContext" parameter, as it allows for debugging and collecting performance information.

Therefore, the reason why the debugger does not start correctly is due to Option A: The "userId" parameter must have the GUID of the user specified, not the username.

In the context provided by the case study, when calling an API action from a mobile application, the correct format for a POST request to an action in Business Central typically involves specifying the entity (/issues), the ID of the entity (88122e0e-5796-ec11-bb87-000d3a392eb5), and the action to be called (/Copy). The action name should match the exact name as defined in the AL code, which is case-sensitive.

Option A is incorrect because it uses a non-standard format for the action call.

Option B uses the PATCH method, which is generally used for update operations, not for calling actions.

Option C is correct as it uses the POST method, which is appropriate for calling actions, and correctly specifies the entity, ID, and action name.

Option D is incorrect because the action name /copy is in lowercase, while AL is case-sensitive, and it should match the case exactly as defined in the code.

Option E incorrectly adds 'MicrosoftNAV' before the action name, which is not standard for calling actions in Business Central APIs.

Hence, the correct action to use when calling the Issue API action from the mobile application is given in Option C.

 XMLport Overview

In Microsoft Dynamics 365 Business Central, XMLports are used for importing and exporting data in XML, CSV, or other text formats. By default, XMLports are designed to work with XML data, but they can also handle delimited text formats like CSV (Comma-Separated Values).

 Requirement Clarification

The requirement is to change the export format from XML to CSV. CSV is a text-based format, not an XML format. To accommodate this, you need to change how the XMLport handles data during export.

 Properties of XMLport

The Format property in XMLports controls whether the output format is XML or a text-based format such as CSV.

The VariableText option of the Format property specifies that the data should be exported in a variable text format, like CSV.

The XMLports default to an XML format, but by setting the Format property to VariableText, you can change the export to CSV format or another text-delimited format.

 Explanation of Correct Answer (E)

To switch from XML to CSV export:

You need to change the Format property of the XMLport to VariableText.

The VariableText option allows for the export of data in a non-XML format, which is precisely what CSV represents (a comma-delimited text file).

 Why Other Options Are Incorrect

Option A (Change the Direction property to Both):The Direction property controls whether the XMLport is used for Import, Export, or Both (import and export), but it does not affect the file format (XML vs. CSV). Hence, this is irrelevant to the file format change.

Option B (Change the FormatEvaluate property to Legacy):The FormatEvaluate property is not related to changing the export format. It deals with the evaluation of the data format during the processing but doesn't change the format type (XML or CSV).

Option C (Change the XmlVeisionNo property to 1.1):The XmlVersionNo property defines the XML version used for the export (such as 1.0 or 1.1). This only applies to XML exports and does not change the format to CSV.

Option D (Fill the FileName property with Items.csv):While this option would specify the name of the file being exported (i.e., "Items.csv"), it doesn't control the format of the export itself. The actual format change is controlled by the Format property.

 Developer Reference from Microsoft Documentation

According to the official Microsoft documentation for XMLports in Business Central, the Format property is critical for determining how data is structured for export. To change the file format from XML to CSV, developers need to set the Format property to VariableText. This allows for export in a text-delimited format, which is ideal for CSV.

XMLport Properties - Format Property

How to: Export Data in Text Format Using XMLports

This event occurs before posting a sales document.

PreviewMode is available in the parameters, which allows checking whether the process is being run in preview mode.

This event is typically used for sales order posting and can be used for both shipping and invoicing.

This event matches the requirements because:

You can check if PreviewMode is false.

It can run for both shipping and invoicing.

 The Part Time Shop Supervisor profile will be applied only to users with "Register Time" = true on User Setup: No

 Variables, procedures, and triggers cannot be added on page customization objects: Yes

 Line 10 should use extends instead of customizes: No

 In line 18, "Unit Cost" will be moved after "Costing Method": Yes

 The Part Time Shop Supervisor profile will be applied only to users with "Register Time" = true on User Setup.

No

The code doesn't contain any reference to the User Setup table or the Register Time field, so this is not correct. Profiles are not applied conditionally based on fields like this.

 Variables, procedures, and triggers cannot be added on page customization objects.

Yes

Page customization objects are meant for UI modifications, such as moving or hiding fields. You cannot add variables, procedures, or triggers in a page customization object.

 Line 10 should use extends instead of customizes.

No

In AL, when customizing a page within a profile, you use customizes rather than extends. Extends is used when modifying base application objects, but customizes is used to customize pages within a profile.

 In line 18, "Unit Cost" will be moved after "Costing Method".

Yes

The code in line 18 is correct. The moveafter directive will move the "Unit Cost" field after the "Costing Method" field on the page layout.