Walkthrough: Transferring a File from Microsoft Dynamics NAV Server to the Client

This walkthrough demonstrates how to develop a codeunit that creates a file on Microsoft Dynamics NAV Server, opens the file, writes some data to it, and then downloads that file to a RoleTailored client.

About This Walkthrough

This walkthrough illustrates the following tasks:

• Creating a codeunit that creates a text file, opens the file, writes some text to the file, and then downloads that file to the client.

• Testing the codeunit.

Prerequisites

To complete this walkthrough, you will need:

• Microsoft Dynamics NAV 2018 installed with a developer license

Creating the Codeunit

The first step is to create the codeunit. In the codeunit, the toFile variable is initially assigned a value of samplefile.txt. If the user specifies another file name, then this new value and the file path are returned in toFile.

To create the codeunit

1. In Object Designer, choose Codeunit and then choose New.

   C/AL Editor opens.

2. Choose the OnRun() function in C/AL Editor.

3. Choose View and then choose C/AL Locals.

   The OnRun -C/AL Locals window opens.

4. Choose the Variables tab.

5. Enter the following local variables.

   Name	DataType	Length
   Name	Text	200
   ReturnValue	Boolean
   TempFile	File
   ToFile	Variant
   NewSteam	InStream

6. Choose the next empty line to ensure that the local variables are saved.

7. Close the C/AL Locals window.

8. Enter the following code in the C/AL Editor for the OnRun() method.

   // Create a temporary file on NAV server, write the content   
   // to the temporary file, and then create an instream for the  
   // temporary file.  
   
   TempFile.CREATETEMPFILE();  
   TempFile.WRITE('abc');  
   TempFile.CREATEINSTREAM(NewStream);  
   ToFile:='SampleFile.txt';  
   
   // Transfer the content from the temporary file on the NAV server to a  
   // file on the RoleTailored client.  
   
   ReturnValue:=DOWNLOADFROMSTREAM(  
     NewStream,  
     'Save File to RoleTailored Client',  
     '',  
     'Text File *.txt| *.txt',  
     ToFile);  
   
   // Close the temporary file and delete it from NAV server.  
   TempFile.CLOSE();  
   
   // Post a message indicating that the file is saved on the client.  
   MESSAGE(FORMAT(ToFile));  
   

9. Save the codeunit, giving it a name of FileTransfer and an ID of 50011.

10. Close the code editor.

Testing the Codeunit

The final step is to test the codeunit.

To test the codeunit

1. In Object Designer, select the codeunit that you created, and then choose the Run button.

   The Export File dialog box appears.

2. Choose Save and save to the default location, noting what that location is.

3. Choose OK.

4. A message box opens specifying the location of the saved file. Choose OK.

5. Browse to the specified file location on your client computer.

6. Open the file.

7. Note that the file contains the text 'abc'.

See Also

Walkthrough: Uploading a File from a Client to Microsoft Dynamics NAV Server