TcxCustomTreeList.RestoreDataViewState(TcxTreeListStorageOptions) Method

Restores user interaction states stored in memory after a StoreDataViewState procedure call.

Declaration

procedure RestoreDataViewState(AOptions: TcxTreeListStorageOptions);

Parameters

Name	Type	Description
AOptions	TcxTreeListStorageOptions	Specifies a set of individual user interaction states stored in memory.

Remarks

Call StoreDataViewState and RestoreDataViewState procedures to save and restore specified user interaction states (selection, focus, node expanded status, etc.) during the same session.

Note

• The RestoreDataViewState procedure also clears all information saved using the StoreDataViewState procedure.
• A RestoreDataViewState procedure call has no effect if no specified (AOptions) user interaction state is stored in memory (for example, if you did not call the StoreDataViewState procedure or saved a different set of user interaction states).

If you need to store user interaction states in a separate stream, call StoreDataViewStateToStream and RestoreDataViewStateFromStream procedures.

Tree List User Interaction States

Pass a set of all required flags^[1] as the AOptions parameter to restore corresponding Tree List user interaction states:

tsoFocusedItem | tsoFocusedRecord

Store/restore the focus position.

tsoSelected

Stores/restores selection.

tsoTopRecord

Stores/restores the Tree List scroll position (the record at the top control border).

tsoExpanded

Stores/restores the expanded status for all nodes.

Note

The tsoUseDataViewState flag has no effect on StoreDataViewState/RestoreDataViewState and StoreDataViewStateToStream/RestoreDataViewStateFromStream calls.

Use tsoUseDataViewState in StoreToIniFile/RestoreFromIniFile, StoreToRegistry/RestoreFromRegistry, and StoreToStream/RestoreFromStream calls to save/restore user interaction states in addition to the data layout.

Code Example: Restore User Interaction States after Data Refresh

The following code example restores selection, focus and scroll positions, and node expanded states after a refresh operation in the bound dataset:

Delphi

uses
  FireDAC.Comp.Client,  // Declares the TFDQuery component
  cxDBTL;  // Declares the TcxDBTreeList class
// ...

  cxDBTreeList1.StoreDataViewState(cxTreeListStoreAllDataViewStates);
  FDQuery1.Refresh;
  cxDBTreeList1.RestoreDataViewState(cxTreeListStoreAllDataViewStates);

C++

#include "FireDAC.Comp.Client.hpp"  // Declares the TFDQuery component
#include "cxDBTL.hpp"  // Declares the TcxDBTreeList class

// Add the following linker directives to the corresponding CPP source file:
#pragma link "FireDAC.Comp.Client" // Required to use FireDAC.Comp.Client.hpp declarations
#pragma link "cxDBTL" // Required to use cxDBTL.hpp declarations

  cxDBTreeList1->StoreDataViewState(cxTreeListStoreAllDataViewStates);
  FDQuery1->Refresh();
  cxDBTreeList1->RestoreDataViewState(cxTreeListStoreAllDataViewStates);

Other Tree List Store/Restore Methods

Alternatively, you can store Tree List data layout and user interaction states in an INI file or the system registry. The TcxCustomTreeList class implements the following Store~/Restore~ method pairs in addition to StoreDataViewState and RestoreDataViewState:

StoreToIniFile | RestoreFromIniFile

Allow you to store the Tree List state (both data layout and user interaction states) in an INI file.

StoreToRegistry | RestoreFromRegistry

Allow you to store the Tree List state (both data layout and user interaction states) in the system registry.

StoreToStream | RestoreFromStream

Allow you to store the Tree List state (both data layout and user interaction states) in a stream.

StoreDataViewStateToStream | RestoreDataViewStateFromStream

Allow you to store user interaction states in a separate stream.

Footnotes

1. Alternatively, you can use only the cxTreeListStoreAllDataViewStates constant if you need to restore all user interaction states for the Tree List control as demonstrated in the code example in this topic.