Linking in DITA Topics
Direct Links
You can create in-line links in the content of a DITA topic using the xref
               element. The destination of the link can be expressed directly by using the
               href attribute and the target can be another topic or a specific element
               within the other topic, another location within the same topic, a file, or a web link.
               You
               can also create direct related links to topics, files, or websites in a DITA
               topic using the related-links element.
            
Indirect Links Using Keys
The destination of the link can also be expressed indirectly by using keys to create either in-line links or related
                  links (with the keyref attribute). By using keys, you avoid
               creating a direct dependency between topics. This makes links easier to manage and
               can make
               it easier to reuse topics in various publications. It can also be helpful in verifying
               the
               completeness of a publication, by ensuring that a publication map provides a key definition
               for every key reference used in the content. 
            
Links based on keys require two pieces:
- Key Definition - Assigns a key to a topic so that other topics can link to it. For more information, see Inserting and Defining Keys in DITA Maps.
- Key Reference - Created in an xrefelement and specifies the key to link to.
topicref element
               that points to a topic. This allows you to assign a particular key to one topic in
               one map
               and to another topic in another map. When a topic that links to that key is used in
               each of
               these maps, the links work correctly in both maps.
            
            
         Inserting a Link in Oxygen XML Editor plugin
To insert a link in Author mode, use the actions available in the
                Link
               drop-down menu from the toolbar (or the
Link
               drop-down menu from the toolbar (or the  Link submenu in the contextual menu or DITA menu).
               You can choose between the following types of in-line links:
Link submenu in the contextual menu or DITA menu).
               You can choose between the following types of in-line links:
            
- Cross Reference
- Opens the Cross Reference (xref) dialog box that allows you
                        to insert a link to a target resource at the current location within a document. The
                        target resource can be the location of a file or a key that is already defined in
                        your
                        DITA map structure. Once the target resource has been selected, you can also target
                        specific elements within that resource. Depending on the context where it is invoked,
                        the action inserts one of the following two elements: - xref- Used to link to other topics or another location within the same topic and points to the target using the- hrefor- keyrefattribute.
- fragref- A logical reference to a fragment element within a syntax diagram and points to the target using the- hrefor- keyrefattribute.
 This dialog box includes the following sections and fields: - Choose the Target Resource Section
- 
                                 
                                 - Location
- If you select Location for the target, the
                                          link is expressed in an hrefattribute.
- Key
- If you select Key for the target, keys will
                                          be used to express the link in a keyrefattribute. You can use the Choose Key Reference button to open the
                                          Choose Key dialog box that allows you to
                                          select one from a list of all the keys that are gathered from the root
                                          map (you can also select one from the drop-down list in the
                                          Key field). Choose Key Reference button to open the
                                          Choose Key dialog box that allows you to
                                          select one from a list of all the keys that are gathered from the root
                                          map (you can also select one from the drop-down list in the
                                          Key field).
 
- Select the Target Element Section
- This section can be used to target a specific element inside the target resource.
                                 - Show elements of type
- You can use this drop-down list to select specific types of elements to be displayed in the subsequent table. This can help you narrow down the list of possible source elements that you can select.
- Text Filter Field
- You can also use the text filter field to narrow down the list of possible source elements to be displayed in the subsequent table.
- Element Table
- Presents all the element IDs defined in the source topic. Use this table to select the Target ID of the element that you want to reference.
- Preview Pane
- Displays the content that will be references.
- Source Pane
- Displays the XML source code of the element to be referenced.
 
 TipYou can easily insert multiple cross references by keeping the dialog box opened, using the Insert button.
- File Reference
- Opens the File Reference dialog box that allows you to insert
                        a link to a target file resource at the current location within a document. The target
                        resource can be the location of a file or a key that is already defined in your DITA
                        map structure. It inserts an xrefelement with either anhrefattribute or akeyrefattribute.- Choose the Target Resource
- 
                                 
                                 - Location
- If you select Location for the target file,
                                          the link is expressed in an hrefattribute.
- Key
- If you select Key for the target file, keys
                                          will be used to express the link in a keyrefattribute. You can use the Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field). Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field).
 
 
- Web Link
- Opens the Web Link dialog box that allows you to insert a
                        link to a target web-related resource at the current location within a document. The
                        target resource can be a URL or a key that is already defined in your DITA map
                        structure. It inserts an xrefelement with either anhrefattribute or akeyrefattribute.- Choose the Target Web Resource
- 
                                 
                                 - URL
- If you select URL for the target resource,
                                          the link is expressed in an hrefattribute.
- Key
- If you select Key for the target resource,
                                          keys will be used to express the link in a keyrefattribute. You can use the Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field). Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field).
 
 
- Related Link to Topic
- Opens the Cross Reference (xref) dialog box that allows you
                        to insert a link to a target resource in a related links section that is typically
                        at
                        the bottom of your topic (although this depends on the behavior of the output
                        transformation). The target resource can be the location of a file or a key that is
                        already defined in your DITA map structure. Once the target resource has been
                        selected, you can also target specific elements within that resource. If a related
                        links section does not already exist, this action creates one. Specifically, it
                        inserts a linkelement inside arelated-linkselement.This dialog box includes the following sections and fields: - Choose the Target Resource Section
- 
                                 
                                 - Location
- If you select Location for the target, the
                                          link is expressed in an hrefattribute.
- Key
- If you select Key for the target, keys will
                                          be used to express the link in a keyrefattribute. You can use the Choose Key Reference button to open the
                                          Choose Key dialog box that allows you to
                                          select one from a list of all the keys that are gathered from the root
                                          map (you can also select one from the drop-down list in the
                                          Key field). Choose Key Reference button to open the
                                          Choose Key dialog box that allows you to
                                          select one from a list of all the keys that are gathered from the root
                                          map (you can also select one from the drop-down list in the
                                          Key field).
 
- Select the Target Element Section
- This section can be used to target a specific element inside the target resource.
                                 - Show elements of type
- You can use this drop-down list to select specific types of elements to be displayed in the subsequent table. This can help you narrow down the list of possible source elements that you can select.
- Text Filter Field
- You can also use the text filter field to narrow down the list of possible source elements to be displayed in the subsequent table.
- Element Table
- Presents all the element IDs defined in the source topic. Use this table to select the Target ID of the element that you want to reference.
- Preview Pane
- Displays the content that will be references.
- Source Pane
- Displays the XML source code of the element to be referenced.
 
 TipYou can easily insert multiple cross references by keeping the dialog box opened, using the Insert button.
- Related Link to File
- Opens the File Reference dialog box that allows you to insert
                        a link to a target file resource in a related links section that is typically at the
                        bottom of your topic (although this depends on the behavior of the output
                        transformation). The target resource can be the location of a file or a key that is
                        already defined in your DITA map structure. If a related links section does not
                        already exist, this action creates one. Specifically, it inserts a
                        linkelement inside arelated-linkselement.- Choose the Target Resource
- 
                                 
                                 - Location
- If you select Location for the target file,
                                          the link is expressed in an hrefattribute.
- Key
- If you select Key for the target file, keys
                                          will be used to express the link in a keyrefattribute. You can use the Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field). Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field).
 
 
- Related Link to Web Page
- Opens the Web Link dialog box that allows you to insert a
                        link to a target web-related resource in a related links section that is typically
                        at
                        the bottom of your topic (although this depends on the behavior of the output
                        transformation). The target resource can be a URL or a key that is already defined
                        in
                        your DITA map structure. If a related links section does not already exist, this
                        action creates one. Specifically, it inserts a linkelement inside arelated-linkselement.- Choose the Target Web Resource
- 
                                 
                                 - URL
- If you select URL for the target resource,
                                          the link is expressed in an hrefattribute.
- Key
- If you select Key for the target resource,
                                          keys will be used to express the link in a keyrefattribute. You can use the Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field). Choose Key Reference
                                          button to open the Choose Key dialog box that
                                          allows you to select one from a list of all the keys that are gathered
                                          from the root map and defined as a non-DITA resource (you can also
                                          select one from the drop-down list in the Key
                                          field).
 
 
Using Copy/Paste Actions to Insert a Cross Reference
Oxygen XML Editor plugin also includes support for inserting cross references with simple
               copy/paste actions. The copied content must be an entire DITA XML element with an
               ID
               attribute or a topicref. Also, the location in the document where you paste
               the link must be valid, although as long as the Smart paste and drag and drop option is enabled in the
               Schema Aware preferences page, if you try to paste it in an invalid
               location, Oxygen XML Editor plugin will attempt to place it in a valid location, and may
               prompt you with one or more choices for where to place it. You can paste the link
               as a cross
               reference with the link expressed in an href attribute or in a
               keyref attribute.
            
To insert a cross reference link (expressed in an href attribute) using
               copy/paste actions, follow these steps:
               
- Copy an entire DITA element that has an ID attribute assigned to it or a
                     topicref.
- Place the cursor at a location, where you want to insert the link.
- Select the Paste as Link action from the  Paste Special submenu from the
                     contextual menu. Paste Special submenu from the
                     contextual menu.
keyref attribute)
               using copy/paste actions, follow these steps:
               - In the DITA Maps Manager view, make sure that the Root map combo box points to the correct map that stores the keys.
- Make sure the topic that contains the content you want to reference has a key assigned to it. To assign a key, right-click the topic with its parent map opened in the DITA Maps Manager, select Edit Properties, and enter a value in the Keys field.
- Copy an entire DITA element that has an ID attribute assigned to it from a topic with
                     an assigned key, or a topicreffrom a DITA map.
- Place the cursor at a location, where you want to insert the link.
- Select the Paste as Link (keyref) action from the
                      Paste Special
                     submenu from the contextual menu. Paste Special
                     submenu from the contextual menu.
 
          