Percentage mask on some cells of the TStringGrid

Question

I have a TStringGrid where I will type in each column a value and I need a mask for the value to appear as a percentage, I am a beginner with Delphi but I saw that there is an OnGetEditMask method but I do not know how to create a mask for the percentage ... then I go manipulate this value into a variable of type Double. Example I enter 5,4 and with the mask gets 5,4%

Then how do I get the list data into Double?

Answer 1

You are correctly assigning the Value parameter in the OnGetEditMask event (assuming your regional settings use decimal comma and not decimal point), repeated here for completeness:

procedure TForm1.StringGrid1GetEditMask(Sender: TObject; ACol, ARow: Integer;
  var Value: string);
begin
  if (ACol = 0) or (ACol = 1) then
    Value := '99,9%';
end;

Then, to convert the string content of the cell to a double, you need to remove the percent sign from the string before you pass it to, e.g. StrToFloatDef():

For example:

procedure TForm1.Button1Click(Sender: TObject);
var
  s: string;
  d: double;
  b: boolean;
begin
  b := False;
  s := StringGrid1.Cells[1, 1];
  if s <> '' then
  begin
    if s[Length(s)] = '%' then
    begin
      s := copy(s, 1, Length(s)-1);
      b := true;
    end;
    d := StrToFloatDef(s, 0.0);
    if b then d := d / 100;
  end;
  ShowMessage(FloatToStr(d));
end;