ISNULLGUID Function (GUID)
Indicates whether a value has been assigned to a GUID. A null GUID that consists only of zeros is valid but must never be used for references.
Syntax
Ok := ISNULLGUID(Guid);
Parameters
Guid
The GUID that you want to check whether it is null.
Property Value/Return Value
Type: Boolean
true if a value has been assigned to the GUID; otherwise, false.
Remarks
The GUID data type is useful when you want to uniquely identify data so that it can be exchanged with external applications. For example, if you want to transfer an item catalog to an external application, you add a GUID field to the record in the table and use it as the primary reference when you communicate with the external application. A GUID is a 16-byte binary data type that can be logically grouped into the following subgroups: 4byte-2byte-2byte-2byte-6byte.
Example
The following example initializes two variables named validGuid and nullGuid. The validGuid variable is assigned a valid GUID value, and the nullGuid variable is assigned a null GUID that consists of only zeros. The ISNULLGUID function determines whether the GUID that is contained in the validGuid parameter is null. In this case, the GUID is not null so a message that states that the GUID is not null is displayed and the value is displayed. The function then checks the nullGuid parameter. This time, a message that states that the GUID is null is displayed because the GUID is a null GUID that consists of only zeros. This example requires that you create the following variables and text constants in the C/AL Globals window.
| Variable name | DataType |
|---|---|
| validGuid | GUID |
| nullGuid | GUID |
| Text constant name | ENU value |
|---|---|
| Text000 | The GUID is null. |
| Text001 | The GUID is not null.\ |
| Text002 | The value is: %1. |
validGuid := '{FC841BE6-0ADA-46C4-A6A9-142AEC211613}';
nullGuid := '{00000000-0000-0000-0000-000000000000}';
IF ISNULLGUID(validGuid) THEN
MESSAGE(Text000)
ELSE
MESSAGE(Text001 + Text002, validGuid);
IF ISNULLGUID(nullGuid) THEN
MESSAGE(Text000);