RAD Studio VCL Reference
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Copies the contents of another collection to the object where the method is executed.
procedure Assign(Source: TPersistent); override;
virtual __fastcall Assign(TPersistent * Source);
Use Assign to copy the contents of one TCollection instance to another. The Assign method deletes all items from the destination collection (the object where it is executed), then adds a copy of each item in the source collection's Items array.
Source is another object (typically another collection) that contains the items that replace this collection's items.
Delphi Examples:
var SavedParams: TParams; { Initialize SavedParams } SavedParams := TParams.Create; try { Save the parameters for SQLDataSet1 } SavedParams.Assign(SQLDataSet1.Params); { Do something with SQLDataSet1 } ... { Restore the parameters to SQLDataSet1 } SQLDataSet1.Params.AssignValues(SavedParams); finally SavedParams.Free; end;
{ This example saves params from a ClientDataSet, alters them and restores them. } procedure TForm1.SaveParamsClick(Sender: TObject); begin { Save the parameters for the TDataSet } SavedParams.Assign(CDS.Params); end; procedure TForm1.AlterParamsClick(Sender: TObject); var I : Integer; begin CDS.Params.CreateParam(ftInteger, 'StateParam', ptInput); CDS.Params.CreateParam(ftInteger, 'MyParam', ptInput); for I := 0 to CDS.Params.Count - 1 do if (CDS.Params.Items[I].IsNull) and (CDS.Params.Items[I].DataType = ftInteger) then { Items is the default property, so you can omit its name } CDS.Params[I].AsInteger := -1; end; procedure TForm1.RestoreParamsClick(Sender: TObject); begin { Restore the parameters to TDataSet } CDS.Params.AssignValues(SavedParams); end; procedure TForm1.FormCreate(Sender: TObject); begin { Initialize SavedParams } SavedParams := TParams.Create; end; procedure TForm1.FormDestroy(Sender: TObject); begin SavedParams.Free; end;
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