delphi Memo1文本搜索并高亮

unit Unit2;

interface

uses

Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,

Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type

TForm2 = class(TForm)

Memo1: TMemo;

Button1: TButton;

Edit1: TEdit;

procedure Button1Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

var

Form2: TForm2;

implementation

{$R *.dfm}

function search(pat: string; text: string): integer;

var

i, j, k, m, n: integer;

skip: array [0..MAXCHAR] of integer;

found: boolean;

begin

found := FALSE;

search := 0;

m := length(pat);

if m=0 then

begin

search := 1;

found := TRUE;

end;

for k:=0 to MAXCHAR do

skip[k] := m; {*** Preprocessing ***}

for k:= m-1 downto 1 do

skip[ord(pat[k])] := m-k;

k := m;

n := length(text); {*** Search ***}

while not found and (k <= n) do

begin

i := k; j := m;

while (j >= 1) do

begin

if text[i] <> pat[j] then

j := -1

else

begin

j := j-1;

i := i-1;

end;

if j = 0 then

begin

search := i+1;

found := TRUE;

end;

k := k + skip[ord(text[k])];

end;

procedure TForm2.Button1Click(Sender: TObject);

var

FoundIdx: Integer;

begin

// search() returns 0 if the text isn't found or the index of the

// start of the string if the text is found

FoundIdx := search(Edit1.Text, Memo1.Text);

if FoundIdx > 0 then

begin

// Found text: highlight it in memo (TMemo.HideSelection must be

// false for this to work). Since memo selections are 0 based, we

// subtract 1 from the found index, which is 1 based.

Memo1.SelStart := FoundIdx - 1;

Memo1.SelLength := Length(Edit1.Text);

Memo1.SetFocus;

end

else

ShowMessage('Text not found');

end;

end.

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