You can share the data from primary, delete, and filter buffers of read-only DataWindow objects across Web Forms application sessions.
Sharing DataWindow objects
The Web.config file global property PBCachedAndSharedDWs is available for this purpose. You must set its value to the string of comma-delimited names of the DataWindow objects you want to share across application sessions.
For information on modifying global properties, see Viewing and Modifying Global Properties in the IIS Manager.
These restrictions apply to DataWindow controls that have a DataWindow object included in the PBCachedAndSharedDWs property setting:
- Only a single invocation of Retrieve is allowed, and the Retrieve call must not include parameters.
- No filtering or sorting is allowed.
- No deletions, insertions, data modifications, or updates are allowed.
- No invocation of ShareData or ShareDataOff is allowed.
When this form of sharing is used, the retrieval events are not fired. This is because the Retrieve method shares the data in the cache and no actual retrieval occurs.
Sharing DDDW objects
It is also possible to share the data of DropDownDataWindow objects across Web Forms application sessions. The global property PBCachedAndSharedDDDWs is used for this purpose. You can set its value to a string of comma-delimited names of DataWindow objects. Each DataWindow object that you list can then be shared as the child DataWindow of a DropDownDataWindow column.
Note: In a Web Forms application, response windows are components of main windows rather than separate browser instances. By default, when a response window is opened, DDDW columns are temporarily hidden behind a layer displaying the response window. The columns become visible again when the response window is closed. You can prevent the temporary visibility issue by changing the value of the PBDataWindowEnableDDDW global property.
For more information about rendering DDDW columns, see DataWindow objects and controls.
The following restrictions apply to DataWindowChild object references included in the PBCachedAndSharedDDDWs property setting:
- No invocation of Retrieve is allowed.
- No filtering or sorting is allowed.
- No deletions, insertions, data modifications, or updates are allowed.
- No invocation of ShareData or ShareDataOff is allowed.