TRichEdit
在设置样式时导致过多的访问冲突和弹出菜单中的问题,因此,我尝试制作一个简单的彩色TMemo
后代,其中Lines
中的每一行都可能是整体上涂有自己的颜色。
我不能影响Windows的编辑控件,但可以在其上绘制字符串。
起初,我尝试遍历Lines
属性,但它导致了滚动问题。因此,我决定直接使用Win API从编辑控件中查询字符串。
目前,除了颜色之外,其他所有东西都被涂上了精细的颜色:Windows编辑控件请求的行是屏幕行,而不是Lines
和WordWrap := True;
时来自ScrollBars := ssVertical;
属性的行。
如何查找屏幕-> Lines
行号对应?
unit ColoredEditMain;
interface
uses
Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;
type
TMyMemo = class(TMemo)
private
procedure WMPaint(var msg: TWMPaint); message WM_PAINT;
end;
TForm1 = class(TForm)
private
_memo: TMyMemo;
public
constructor Create(AOwner: TComponent); override;
end;
var
Form1: TForm1;
implementation
uses
Vcl.Themes;
{$R *.dfm}
{ TMyMemo }
procedure TMyMemo.WMPaint(var msg: TWMPaint);
var
Buffer: Pointer;
PS: TPaintStruct;
DC: HDC;
i: Integer;
X, Y: Integer;
OldColor: LongInt;
firstLineIdx: Integer;
charsCopied, lineCount: Integer;
lineLength: Word;
bufLength: Integer;
begin
try
DC := msg.DC;
if DC = 0 then
DC := BeginPaint(Handle, PS);
try
X := 5;
Y := 1;
SetBkColor(DC, Color);
SetBkMode(DC, Transparent);
OldColor := Font.Color;
firstLineIdx := SendMessage(Handle, EM_GETFIRSTVISIBLELINE, 0, 0);
lineCount := SendMessage(Handle, EM_GETLINECOUNT, 0, 0);
for i:=firstLineIdx to lineCount-1 do begin
SelectObject(DC, Font.Handle);
if odd(i) then
SetTextColor(DC, clRed)
else
SetTextColor(DC, OldColor);
lineLength := SendMessage(Handle, EM_LINELENGTH, WPARAM(i), 0);
bufLength := lineLength*2 + 2;
GetMem(Buffer, bufLength);
try
ZeroMemory(Buffer, bufLength);
PWord(Buffer)^ := lineLength;
charsCopied := SendMessage(Handle, EM_GETLINE, WPARAM(i), LPARAM(Buffer));
//ShowMessage(IntToStr(lineLength) + ' ' + IntToStr(charsCopied) + '=' + Strpas(PWideChar(Buffer)));
if Y > ClientHeight then Exit();
TextOut(DC, X, Y, PWideChar(Buffer), lineLength);
finally
FreeMem(Buffer, bufLength);
end;
Inc(Y, Abs(Font.Height) + 2);
end;
finally
if msg.DC = 0 then
EndPaint(Handle, PS);
end;
except
on ex: Exception do MessageBox(Handle, PWideChar('WMPaint: ' + ex.Message), nil, MB_ICONERROR);
end;
end;
{ TForm1 }
constructor TForm1.Create(AOwner: TComponent);
var
i, j: Integer;
txt: string;
begin
inherited;
Left := 5;
Top := 5;
_memo := TMyMemo.Create(Self);
_memo.Parent := Self;
_memo.Align := alClient;
_memo.WordWrap := True;
_memo.ReadOnly := True;
_memo.ScrollBars := ssVertical;
for i := 0 to 10 do begin
txt := '';
for j := 0 to 100 do
txt := txt + 'Line ' + IntToStr(i) + '.' + IntToStr(j) + ' ';
_memo.Lines.Add(txt);
end;
end;
end.
更新
我一直认为TMemo
将原始行保留在其Lines
集合中,但是实际上,它在添加项目之后就破坏了其Lines
。启用自动换行时,添加很长的行会将其转换为几行屏幕。
但是!令人惊讶的是,Windows edit
控件在内部将原始行作为控件调整大小的整体。