var S: string;begin S := ' 123.5'; { Convert spaces to zeros } while Pos(' ', S) > 0 do S[Pos(' ', S)] := '0'; end;
procedure TForm1.ComboBox1KeyPress(Sender: TObject; var Key: Char);var Found: boolean; i,SelSt: Integer; TmpStr: string; begin { first, process the keystroke to obtain the current string } { This code requires all items in list to be uppercase} if Key in ['a'..'z'] then Dec(Key,32); {Force Uppercase only!} with (Sender as TComboBox) do begin SelSt := SelStart; if (Key = Chr(vk_Back)) and (SelLength <> 0) then TmpStr := Copy(Text,1,SelStart)+Copy(Text,SelLength+SelStart+1,255) else if Key = Chr(vk_Back) then {SelLength = 0} TmpStr := Copy(Text,1,SelStart-1)+Copy(Text,SelStart+1,255) else {Key in ['A'..'Z', etc]} TmpStr := Copy(Text,1,SelStart)+Key+Copy(Text,SelLength+SelStart+1,255); if TmpStr = '' then Exit; { update SelSt to the current insertion point } if (Key = Chr(vk_Back)) and (SelSt > 0) then Dec(SelSt) else if Key <> Chr(vk_Back) then Inc(SelSt); Key := #0; { indicate that key was handled } if SelSt = 0 then begin Text:= ''; Exit; end; {Now that TmpStr is the currently typed string, see if we can locate a match } Found := False; for i := 1 to Items.Count do if Copy(Items[i-1],1,Length(TmpStr)) = TmpStr then begin Text := Items[i-1]; { update to the match that was found } ItemIndex := i-1; Found := True; Break; end; if Found then { select the untyped end of the string } begin SelStart := SelSt; SelLength := Length(Text)-SelSt; end else Beep; end; end;
S := ' 123.5';
{ Convert spaces to zeros }
while Pos(' ', S) > 0 do
S[Pos(' ', S)] := '0';
end;
Found: boolean;
i,SelSt: Integer;
TmpStr: string;
begin
{ first, process the keystroke to obtain the current string }
{ This code requires all items in list to be uppercase}
if Key in ['a'..'z'] then Dec(Key,32); {Force Uppercase only!}
with (Sender as TComboBox) do
begin
SelSt := SelStart;
if (Key = Chr(vk_Back)) and (SelLength <> 0) then
TmpStr := Copy(Text,1,SelStart)+Copy(Text,SelLength+SelStart+1,255) else if Key = Chr(vk_Back) then {SelLength = 0}
TmpStr := Copy(Text,1,SelStart-1)+Copy(Text,SelStart+1,255)
else {Key in ['A'..'Z', etc]}
TmpStr := Copy(Text,1,SelStart)+Key+Copy(Text,SelLength+SelStart+1,255);
if TmpStr = '' then Exit;
{ update SelSt to the current insertion point } if (Key = Chr(vk_Back)) and (SelSt > 0) then Dec(SelSt) else if Key <> Chr(vk_Back) then Inc(SelSt);
Key := #0; { indicate that key was handled }
if SelSt = 0 then
begin
Text:= '';
Exit;
end; {Now that TmpStr is the currently typed string, see if we can locate a match } Found := False;
for i := 1 to Items.Count do
if Copy(Items[i-1],1,Length(TmpStr)) = TmpStr then
begin
Text := Items[i-1]; { update to the match that was found }
ItemIndex := i-1;
Found := True;
Break;
end;
if Found then { select the untyped end of the string }
begin
SelStart := SelSt;
SelLength := Length(Text)-SelSt; end
else Beep;
end;
end;
我记得 Delphi 里有现成的函数,只需给定起始位和长度.好像是 xxxxCopy() ?
copy('abcdefg',3,4)