IMPORTSTREAM Function (Media)

Artikel
06/05/2016

Adds a media type (MIME), such as jpeg image, from an InStream object to a Media data type field of a record for displaying the media in the client. The media file is imported to the application database and a reference to the media is included in the Media data type field.

Syntax

[Guid := ]Record.MediaField.IMPORTSTREAM(InStream, Description[, MimeType])

Parameters

Record
Type: Record

Specifies the record that you want to add the media to.

MediaField
Type: Media

Specifies the field that you want to add the media to. This field must be a Media data type.

InStream
Type: InStream

Specifies the InStream object that contains the media that you want to use on the record.

Description
Type: Text

Specifies text that can be used in the client to describe the media file.

MimeType
Type: Text

Specifies the media content type. MIME type is used by browsers, and is an Internet standard to describe the contents of a file. The MimeType value must be a two-part string that consists of a type and subtype, such as image/jpeg or image/gif. For more information, see Supported Media Types.

If this parameter is not specified, the function will deduce the MIME type from the file extension. For example the MIME type for a .jpg file is image/jpeg.

Property Value/Return Value

Type: GUID

Specifies the unique ID that is assigned to the imported media object in the database table field. You can also retrieve the ID by using the MEDIAID Function (Media).

Remarks

You can use this function to import media into the database, and associate the media with a record. For example, you can upload an image of all items in table 27 Item. When media is imported, the object is stored in the system table 2000000184 Tenant Media of the application database.

If you import media on a record that already has a media object, and a modify operation is performed, the original media object will be permanently deleted from the database. However, if there are other rows in the same table that reference the original media object from the same field index, the original media object is not deleted from the database. This behavior allows a row to be copied.

Example

Preparation:
To support the example code that follows, create the following objects:

A table that is named My Items and has the following characteristics (as a minimum):
- An Integer data type field that has the name No..
  
  This field is used to give an item a number.
- A Media data type field that has the name Image.
  
  This is the field on which you will import the media file.
- A field group that has the name Brick and includes the No. and Image fields.
  
  The field group is used to display the image on a page in the brick layout. For more information, see How to: Display Data as Bricks.
A page that is named My Items and has the following characteristics:
- List type page that uses the My Items table as its source.
- A repeater control that contains the fields of the My Items table.
  
  Note
  
  It is not necessary to include the Media data type field on the page.
Use the page to add one or more items to the table, assigning each item a number like 1,2,3, and so on.
JPEG image files for one or more items in the My Items table.
- Give each file a name that corresponds to an item number in the table, such as 1.jpg, 2.jpg, 3.jpg, and so on.
- Save the files in the C:\images folder on the computer that is running Microsoft Dynamics NAV Server.

Code
With the objects in place, you can add and run the following C/AL code to import the images. For this code example, create a codeunit and add the code to the OnRun trigger of the codeunit.

This code iterates over records in the My Items table. For each record, it looks in the C:\images folder for a file whose name matches the No. field of the record. If there is a match the file, an InStream object is created for the file, the media is imported into the record, and a confirmation message is returned.

The code requires that you create the following variable and text constants:

Variable name	DataType	Subtype
myItemRec	Record	My Items
fileName	Text
importFile	File
imageInStream	InStream
imageID	GUID

Text constant name	ConstValue
Text000	An image with the following ID has been imported on item %1: %2

IF  myItemRec.FINDFIRST() THEN  
BEGIN  
  REPEAT  
    fileName := 'C:\images\' + FORMAT(myItemRec."No.") + '.jpg';  

    IF FILE.EXISTS(fileName) THEN BEGIN  
        importFile.OPEN(fileName);  
        importFile.CREATEINSTREAM(imageInstream);  
        imageID := myItemRec.Image.IMPORTSTREAM(imageInstream, 'Demo image for item ' + FORMAT( myItemRec."No."));  
        myItemRec.MODIFY;  
        MESSAGE(Text000, myItemRec."No.", imageID);  
        importFile.CLOSE;
    END;  
  UNTIL myItemRec.NEXT < 1;  
END;

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