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TWebClientDataSet

Description

TWebClientDataSet is the class for an in browser memory dataset. Client datasets can work with data retrieved from a REST request or by directly assigning JSON arrays. They cache that data in memory, maintain a record of any changes in a change log, and apply cached updates at a later point back to the source of the data.

Properties for TWebClientDataSet

Property Description
Active Specifies whether or not a dataset is open
Connection Sets the TWebClientConnection component that can take care of performing the REST requests to load the data in the TWebClientDataSet.
DataSource Represents the data source of another dataset that supplies values to the dataset.
Fields Use Fields to access field components. If fields are generated dynamically at runtime, the order of field components in Fields corresponds directly to the order of columns in the table or tables underlying a dataset. If a dataset uses persistent fields, then the order of field components corresponds to the ordering of fields specified in the Fields editor at design time.
FieldDefs Points to the list of field definitions for the dataset.
Params Use Params to specify parameter values that the provider should pass to a source dataset
RecNo Indicates the active record in the dataset.
RecordCount Returns the number of records in the dataset
Rows: TJSArray JSON array property allow to set the dataset data from a JSON array

Methods for TWebClientDataSet

Method Description
ApplyUpdates Sends all updated, inserted, and deleted records from the client dataset to the provider for writing to the database.
Cancel Cancels unposted changes to the current record.
ClearFields Removes all fields from the fields collection
Close Closes the dataset. Equivalent to setting Active = false
Delete Deletes the active record and positions the dataset on the next record.
Edit Sets the dataset in edit mode
EmptyDataSet Removes all data (records) from the dataset
First Moves to the first record in the dataset.
Insert Puts the dataset in insert state
Last Moves to the last record in the dataset.
Next Moves to the next record in the dataset.
Open Opens the dataset. Equivalent to setting Active = true
Post Writes a modified record to the Data property or the change log.
Prior Moves to the previous record in the dataset

Events for TWebClientDataSet

Event Description
AfterCancel Event triggered after a cancel operation on the dataset
AfterClose Event triggered after a dataset close
AfterDelete Event triggered after a delete operation on the dataset
AfterEdit Event triggered after the dataset was set in edit mode
AfterInsert Event triggered after the dataset was set in insert mode
AfterOpen Event triggered after a dataset open
AfterPost Event triggered after a post operation on the dataset
AfterScroll Event triggered after a scroll
BeforeCancel Event triggered just before a cancel operation will be performed on the dataset
BeforeClose Event triggered just before the dataset will be effectively closed
BeforeDelete Event triggered just before a delete operation will be performed on the dataset
BeforeEdit Event triggered just before the dataset is set into edit mode
BeforeInsert Event triggered just before an insert operation will be performed on the dataset
BeforeOpen Event triggered just before the dataset will be effectively opened
BeforePost Event triggered just before a post operation will be performed on the dataset
BeforeScroll Event triggered just before a scroll will happen in the dataset
OnCalcFields Occurs when an application recalculates calculated fields.
OnDeleteError Occurs when an application attempts to delete a record and an exception is raised.
OnEditError Occurs when an application attempts to modify or insert a record and an exception is raised.
OnFilterRecord Occurs each time a different record in the dataset becomes the active record and filtering is enabled.
OnNewRecord Occurs when an application inserts or appends a new dataset record.
OnPostError Occurs when an application attempts to modify or insert a record and an exception is raised.
OnUpdateRecord Occurs when cached updates are applied to a record.