三通管.如何删除以前在图表上添加的文本

我建议你试试这个：

procedure TForm1.Button1Click(Sender: TObject);
begin
FRectTool := Chart1.Tools.Add(TRectangleTool) as TRectangleTool;
with FRectTool do begin
Text:='THIS A TEXT';
Shape.Angle:=0;
Shape.Transparency:=0;
Shape.Pen.Hide;
Shape.AutoSize:=True;
Shape.Color := Talphacolorrec.null;
Shape.Font.Name:='Segoe UI';
Shape.Font.Size := 14;
Shape.Font.Color := Talphacolorrec.red;
AllowDrag:=False;
AllowResize:=False;
Left:= 4;
Top:= 0;
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
Index : Integer;
begin
Index := Chart1.Tools.IndexOf(FRectTool);
Chart1.Tools.Delete(Index);
FreeAndNil(FRectTool);  // Not sure it must be called
end;

您必须在表单类中声明FRectTool

private
FRectTool: TTeeCustomTool;

BTW：我不能自己尝试，因为我没有TeeChart Pro。发布一条评论来判断它是否有效。如果不起作用，请公布您收到的错误。

Var
myrectangle :  array[0..2] of TrectangleTool;
indexrectangle :  array[0..2] of integer;
i, j : integer;
//delete previous Trectangletools
for i := 0 to form1.Chart1.Tools.Count-1 do
If form1.Chart1.Tools[i] is  TRectangleTool then form1.Chart1.Tools[i].destroy;
//adding two Trectangletools
form1.Chart1.Tools.Add(TRectangleTool);
form1.Chart1.Tools.Add(TRectangleTool);
j:= -1;
for i := 0 to form1.Chart1.Tools.Count-1 do
If form1.Chart1.Tools[i] is  TRectangleTool then
begin
inc(j);
indexRectangle[j] := i;
myrectangle[i] := form1.Chart1.Tools.Items[i] as TRectangleTool;
end;
//Defining  the two new Trectangletools
with myrectangle[indexRectangle[0]] do
begin
Text :=' 1 this is a text 1';
Shape.Angle:=0;
Shape.Transparency:=0;
Shape.Pen.Hide;
Shape.AutoSize:=True;
Shape.Color := Talphacolorrec.null;
// Shape.Font.Style:=[fsBold];
Shape.Font.Name:='Segoe UI';
Shape.Font.Size := 14;
Shape.Font.Color := Talphacolorrec.Blue;
AllowDrag:=False;
AllowResize:=False;
Left:= 4;
//Chart1.ChartRect.Left-5;
Top:= 0;
//Chart1.ChartRect.Bottom-40;
end;
with myrectangle[indexRectangle[1]] do
begin
Text :='2 this is a text 2';
Shape.Angle:=0;
Shape.Transparency:=0;
Shape.Pen.Hide;
Shape.AutoSize:=True;
Shape.Color := Talphacolorrec.null;
// Shape.Font.Style:=[fsBold];
Shape.Font.Name:='Segoe UI';
Shape.Font.Size := 14;
Shape.Font.Color := Talphacolorrec.red;
AllowDrag:=False;
AllowResize:=False;
Left:= 200;
Top:= 0;

end;