Firemonkey网格控制 - 根据值（通过OnGetValue函数调用）对单元格进行样式化

问题描述

我正在寻找推荐的解决方案来设计正在由OnGetValue调用绘制的TGrid单元格（这被称为在视图中绘制单元格）。对于背景，Mike的出色响应显示了如何在创建单元格时简单应用tAlign属性;但我的下一个挑战是着色单元格内容。

I am looking for recommended solution to style a TGrid cell that is being drawn by the OnGetValue call (that is called to paint the cells in view). For background, an excellent response by Mike, showed how to simply apply a tAlign property when the cell is created; but my next challenge is colouring the cell contents.

目的是改变单元格属性（字体，样式，颜色等） ..）我将要作为单元格值返回的值。在下面的例子中它将对正在返回的OnGetValue值应用样式。很可能我们必须通过FM样式表来做到这一点;或者我们可以直接获取TText属性吗？理想情况下，这两种情况都会很好 - 但是在这个阶段我将采取任何解决方案...（; - >

The objective is to change the cell attributes (Font, style, colour etc...) of the value I am about to return as the cell "Value". In the example below; it would be applying a style to the OnGetValue "value" that is being returned. It may well be that we have to do this via a FM Stylesheet; or can we get directly to the TText attributes? Ideally, both scenarios would be great - but at this stage I will take either solution... (;->

unit Unit1;

interface

uses
  System.SysUtils, System.Types, System.UITypes, System.Classes, System.Variants,
  FMX.Types, FMX.Controls, FMX.Forms, FMX.Dialogs, FMX.Objects, FMX.Grid,
  FMX.Layouts, FMX.Edit;

type
  TForm1 = class(TForm)
    Grid1: TGrid;
    Button1: TButton;
    StyleBook1: TStyleBook;
    procedure Grid1GetValue(Sender: TObject; const Col, Row: Integer;
      var Value: Variant);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

  TStringColNum = class(TStringColumn)
  private
    function CreateCellControl: TStyledControl; override;
  published
  end;

var
  Form1: TForm1;

implementation

{$R *.fmx}

function TStringColNum.CreateCellControl: TStyledControl;
begin
  Result:=TTextCell.Create(Self);
  TTextCell(Result).TextAlign := TTextAlign.taTrailing;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  Grid1.AddObject(TStringColumn.Create(Self));
  Grid1.AddObject(TStringColNum.Create(Self)); // Right Aligned column?

  Grid1.RowCount:=5000;
  Grid1.ShowScrollBars:=True;
end;

procedure TForm1.Grid1GetValue(Sender: TObject; const Col, Row: Integer;
  var Value: Variant);
begin
  if Col=0 then
    Value:='Row '+IntToStr(Row);

  if Col=1 then
    Value := 'Row '+IntToStr(Row);

// Apply style based on value ?

end;

end.

非常感谢提前，
Ian。

Many thanks in advance,Ian.

推荐答案

首先，道歉。在我对最后一个问题的回答中，CreateCellControl应该已经调用继承来创建单元格。我已经修改了我的答案。

Firstly, an apology. In my answer to your last question, CreateCellControl should have called inherited to create the cell. I've amended my answer.

至于这个问题，我已经在FireMonkey Cells上传了我的博客文章 - - 它涵盖了以前的答案中的内容，还包括创建自定义单元格控件。在继续之前，您需要阅读。我会等待。

As for this question, I've uploaded my blog posting on FireMonkey Cells - http://monkeystyler.com/blog/entry/firemonkey-grid-basics-custom-cells-and-columns - it covers the stuff from the previous answer, and also covers creating custom cell controls. You'll need to read that before your proceed. I'll wait.

...

从博客文章中的例子继续。

Following on from the example in the blog post.

除了我更新了TFinancialCell直接从TTextCell（当然是一个TEdit）继承，这样做更有意义，而且风格更简单。

Except, that I've updated the TFinancialCell to inherit directly from TTextCell (which of course is a TEdit), which makes far more sense and is far simpler to style.

所以，更新TFinancialCell： p>

So, update the TFinancialCell:

type TFinancialCell = class(TTextCell)
  private
    FIsNegative: Boolean;
    FIsImportant: Boolean;
  protected
    procedure SetData(const Value: Variant); override;
    procedure ApplyStyle;override;
    procedure ApplyStyling;
  public
    constructor Create(AOwner: TComponent); override;
  published
    property IsNegative: Boolean read FIsNegative;
    property IsImportant: Boolean read FIsImportant;
  end;

上述代码：

procedure TFinancialCell.ApplyStyle;
var T: TFMXObject;
begin
  inherited;
  ApplyStyling;
end;

procedure TFinancialCell.ApplyStyling;
begin
  if IsNegative then
    FontFill.Color := claRed
  else
    FontFill.Color := claBlack;
  Font.Style := [TFontStyle.fsItalic];
  if IsImportant then
    Font.Style := [TFontStyle.fsBold]
  else
    Font.Style := [];
  if Assigned(Font.OnChanged) then
    Font.OnChanged(Font);
  Repaint;
end;

constructor TFinancialCell.Create(AOwner: TComponent);
begin
  inherited;
  TextAlign := TTextAlign.taTrailing;
end;

procedure TFinancialCell.SetData(const Value: Variant);
var F: Single;
  O: TFMXObject;
  S: String;
begin
  S := Value;
  FIsImportant := S[1] = '#';
  if IsImportant then
    S := Copy(Value,2,MaxInt)
  else
    S := Value;

  F := StrToFloat(S);
  inherited SetData(Format('%m', [F]));
  FIsNegative := F < 0;
  ApplyStyling;
end;

最后，更新GetValue事件处理程序：

And finally, update the GetValue event handler:

procedure TForm1.Grid1GetValue(Sender: TObject; const Col, Row: Integer;
  var Value: Variant);
var Cell: TStyledControl;
begin
  if Col = 0 then
    Value := Row
  else if Col = 1 then
  begin
    Value := FloatToStr(Data[Row]);
    if Value > 30 then
      Value := '#'+Value;
  end;
end;

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