C# 的 Delphi `VarArrayCreate` 替代方案是什么？

问题描述 投票：0回答：4

我有一个用 Delphi 编程语言编写的程序，我必须使用 Visual Studio 将其转换为 C#。我已经完成了大部分转换，但遇到了一些挑战 

VarArrayCreate
。

我有的是这个：

Line := VarArrayCreate([0, 1], varVariant);

我似乎无法找到转换或替代 

VarArrayCreate
。

我知道 C# 中的对象可以用于 Variant 替代品，但上面的内容让我陷入困境。

任何帮助都会很棒。

我在下面添加了 Delphi 代码。我对程序感兴趣

TForm1.Button3Click(Sender: TObject);
程序：

unit Unit1;

(*------------------------------------------------------------------------------
DX Atlas Automation demo #2 (early binding)

Make sure that DX Atlas is installed.

Requires DxAtlas_TLB. You can either generate this file in Delphi
(Project -> Import Type Library -> DxAtlas) or use the one included
with this demo.

http://www.dxatlas.com
------------------------------------------------------------------------------*)

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  OleServer, StdCtrls, DxAtlas_TLB, ActiveX, AxCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    CheckBox1: TCheckBox;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Button6: TButton;
    procedure FormShow(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);
  private
    { Private declarations }
  public
    Atlas: IAtlas;
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

//------------------------------------------------------------------------------
//                             Start DX Atlas
//------------------------------------------------------------------------------
procedure TForm1.FormCreate(Sender: TObject);
begin
  //connect to Dx Atlas on program startup
  try
    Atlas := CoAtlas.Create;
  except on E: Exception do
    begin
    ShowMessage('Cannot connect to DX Atlas: ' + E.Message);
    Application.Terminate;
    end;
  end;
end;


procedure TForm1.FormShow(Sender: TObject);
var
  WorkArea: TRect;
begin
  //get Desktop work area dimensions
  SystemParametersInfo(SPI_GETWORKAREA, 0, @WorkArea, 0);


  //form placement
                        
  Top := WorkArea.Top;
  Left := WorkArea.Left;
  Height := WorkArea.Bottom - WorkArea.Top;


  //atlas placement

  //stop repainting
  Atlas.Map.BeginUpdate;
  //place window
  Atlas.Top := Top;
  Atlas.Left := Left + Width;
  Atlas.Width := WorkArea.Right - Left - Width;
  Atlas.Height := Height;
  //hide prefixes
  Atlas.Map.PrefixesVisible := false;
  //now allow repainting
  Atlas.Map.EndUpdate;
  //show the Atlas window
  Atlas.Visible := true;
end;

//------------------------------------------------------------------------------
//                                  Points
//------------------------------------------------------------------------------
procedure TForm1.Button1Click(Sender: TObject);
var
  Pt, Points: OleVariant;
  i: integer;
  Layer: ICustomLayer;
begin
  Randomize;

  //create Variant array for data
  Points := VarArrayCreate([0, 999], varVariant);

  //fill the array with random points

  for i:=0 to 999 do
    begin
    //each point is a variant array with 2 elements
    Pt := VarArrayCreate([0,1], varVariant);
    //point coordinates are random (decimal degrees)
    Pt[0] := Random(360) - 180; //longitude
    Pt[1] := Random(180) - 90;  //latitude
    //add point to the data array
    Points[i] := Pt;
    end;

  //show data on the map

  Atlas.Map.BeginUpdate;
  with Atlas.Map do
    try

      Projection := PRJ_RECTANGULAR;
      Dimmed := false;
      CustomLayers.Clear;
      //add new custom layer
      Layer := CustomLayers.Add(LK_POINTS);
      with Layer do
        begin
        //set layer attributes
        PenColor := clBlue;
        BrushColor := clLime;
        PointSize := 2;
        //set data
        SetData(Points);
        end;
    finally
      EndUpdate;
    end;
end;

//------------------------------------------------------------------------------
//                                  Labels
//------------------------------------------------------------------------------
procedure TForm1.Button2Click(Sender: TObject);
var
  //Lb: Variant;
  Labels: Variant;
  i: integer;
  Layer: ICustomLayer;
begin
  Randomize;

  Labels := VarArrayCreate([0, 999], varVariant);

  for i:=0 to 999 do
    begin
    //each label is a variant array of 3 Variants
    Labels[i] := VarArrayOf([Random(360) - 180,           //longitude
                            Random(180) - 90,             //latitude
                            Format(' LABEL #%d ', [i])]); //label text

    //alternate way of creating and filling the array
    {
    Lb := VarArrayCreate([0,2], varVariant);
    Lb[0] := Random(360) - 180;
    Lb[1] := Random(180) - 90;
    Lb[2] := Format(' Label #%d ', [i]);
    Labels[i] := Lb;
    }
    end;


  Atlas.Map.BeginUpdate;
  with Atlas.Map do
   try
     Projection := PRJ_RECTANGULAR;
     Dimmed := false;
     CustomLayers.Clear;
     Layer := CustomLayers.Add(LK_LABELS);
     with Layer do
       begin
       LabelsTransparent := CheckBox1.Checked;
       //label BG if not transparent
       BrushColor := clAqua;
       //font attributes

       with (Font as IFont) do
         begin
         Put_Name('Courier New');
         Put_Italic(true);
         Put_Size(9);

         //Put_Name('Small fonts');
         //Put_Size(5);
         end;

       //font color
       PenColor := clBlue;
       //data
       SetData(Labels);
       end;
   finally
     EndUpdate;
   end;
end;


//------------------------------------------------------------------------------
//                                  Lines
//------------------------------------------------------------------------------
procedure TForm1.Button3Click(Sender: TObject);
var
  Pt, Line, Meridians, Parallels: OleVariant;
  i, j: integer;
begin
  //generate meridians
  Meridians := VarArrayCreate([0, 7], varVariant);
  for i:=0 to 7 do
    begin
    Line := VarArrayCreate([0, 36], varVariant);
    for j:=0 to 36 do
      begin
      Pt := VarArrayCreate([0, 1], varVariant);
      Pt[0] := i*45 - 180;
      Pt[1] := j*5 - 90;
      Line[j] := Pt;
      end;
    Meridians[i] := Line;
    end;

  //generate parallels
  Parallels := VarArrayCreate([0, 2], varVariant);
  for i:=0 to 2 do
    begin
    Line := VarArrayCreate([0, 72], varVariant);
    for j:=0 to 72 do
      begin
      Pt := VarArrayCreate([0, 1], varVariant);
      Pt[0] := j*5 - 180;
      Pt[1] := i*45 - 45;
      Line[j] := Pt;
      end;
    Parallels[i] := Line;
    end;

  //show on the map

  Atlas.Map.BeginUpdate;
  with Atlas.Map do
   try
     Projection := PRJ_AZIMUTHAL;
     Dimmed := false;
     CenterLatitude := 43;
     CenterLongitude := -79;
     CustomLayers.Clear;

     //show meridians
     with CustomLayers.Add(LK_LINES) do
       begin
       PenColor := clBlue;
       SetData(Meridians);
       end;

     //show parallels
     with CustomLayers.Add(LK_LINES) do
       begin
       PenColor := clRed;
       SetData(Parallels);
       end;

   finally
     EndUpdate;
   end;
end;


//------------------------------------------------------------------------------
//                                  Area
//------------------------------------------------------------------------------
procedure TForm1.Button4Click(Sender: TObject);
var
  Pt, Area, Areas: OleVariant;
  i: integer;
begin
  //single area
  Areas := VarArrayCreate([0, 0], varVariant);

  //generate area data
  Area := VarArrayCreate([0, 72], varVariant);
  for i:=0 to 72 do
    begin
    Pt := VarArrayCreate([0, 1], varVariant);
    Pt[0] := -79 + 20 * cos(i*5/180*Pi);
    Pt[1] := 43 + 20 * sin(i*5/180*Pi);
    Area[i] := Pt;
    end;

  Areas[0] := Area;

  //show on the map
  Atlas.Map.BeginUpdate;
  with Atlas.Map do
   try
     Projection := PRJ_RECTANGULAR;
     Dimmed := true;
     CustomLayers.Clear;
     with CustomLayers.Add(LK_AREAS) do
       begin
       AreaBrightness := 12; //0..15, 15=max
       SetData(Areas);
       end;
   finally
     EndUpdate;
   end;
end;



//------------------------------------------------------------------------------
//                                  Glyphs
//------------------------------------------------------------------------------
procedure TForm1.Button5Click(Sender: TObject);
var
  Glyphs: Variant;
  i: integer;
  Layer: ICustomLayer;
begin
  Randomize;

  //create array of Variants
  Glyphs := VarArrayCreate([0,333], varVariant);
  //each element of the array is a variant array with 3 elements
  for i:=0 to 333 do
    Glyphs[i] := VarArrayOf([Random(360)-180, //longitude    -180..180
                             Random(180)-90,  //latitude     -90..90
                             Random(10)]);    //image index   0..9


  Atlas.Map.BeginUpdate;
  with Atlas.Map do
   try
     Projection := PRJ_RECTANGULAR;
     Dimmed := false;
     //delete all layers
     CustomLayers.Clear;
     //add layer
     Layer := CustomLayers.Add(LK_GLYPHS);
     //Glyphs.bmp is a bitmap 160x16 that contains 10 glyphs, 16x16 each
     //the color of lower left pixel (clFuchsia) is considered transparent
     //the hot spot of the glyph is at (1, 15).
     Layer.LoadGlyphsFromFile(ExtractFilePath(ParamStr(0)) + 'Glyphs.bmp', 1, 15);
     //send locations to the layer
     Layer.SetData(Glyphs);
   finally
     //now allow repainting
     EndUpdate;
   end;
end;



//------------------------------------------------------------------------------
//                            Great Circle paths
//------------------------------------------------------------------------------
procedure TForm1.Button6Click(Sender: TObject);
var
  Pt, Line, Lines: Variant;
  i, j: integer;
begin
  //generate an array of Great Circle paths

  Lines := VarArrayCreate([0, 33], varVariant);
  for i:=0 to 33 do
    begin
    //a Great Circle path is defined by its end points
    Line := VarArrayCreate([0, 1], varVariant);
    Line[0] := VarArrayOf([-79, 43 {Toronto}]);
    Line[1] := VarArrayOf([Random(360) - 180, Random(180) - 90]);
    //add path to the array
    Lines[i] := Line;
    end;

  //show paths on the map

  Atlas.Map.BeginUpdate;
  with Atlas.Map do
   try
     Projection := PRJ_RECTANGULAR;
     Dimmed := false;
     CustomLayers.Clear;
     with CustomLayers.Add(LK_LINES) do
       begin
       PenColor := clBlue;
       SetData(Lines);
       end;
   finally
     EndUpdate;
   end;

  //Note that Delphi automatically releases the variant arrays when they go out of scope.
  //In other languages you may have to release them explicitly.
end;


end.
c# delphi
4个回答
3
投票

示例中的 VarArrayCreate 调用正在创建一个包含 2 个元素的数组，从索引 0 开始到索引 1 结束。

C# 的等价物是这样的：

object[] Line;
Line = new object[2];
1
投票

也许应该提到，varArray 创建了一个变体数据类型的数组，这与普通类型有很大不同。它在内存中创建一个无法与对象实例进行比较的结构（AFAIK）。它预计将存储为相互链接（通过指针）的节点列表。然而，Delphi 变体结构与微软自己的存储格式相同，这意味着你可以调用 winapi 来实现同样的事情。

如果你还没有解决这个问题，我会看看.NET 中的 COM 支持库。可能在“System.Runtime.InteropServices”下。或者查看Delphi中的variants.pas单元，看看它们调用了什么WinAPI函数。

1
投票
private void _showPoints()
{
  object[] pt = new object[2];
  object[] points = new object[4];

  for (int i = 0; i < 3; i++)
  {
    pt[0] = _dx[i, 0];
    pt[1] = _dx[i, 1];
    points[i] = pt;
  }
  _aquaPoints.SetData(points);
}

上面是 Alex 的 VB 代码中的 ShowPoints 方法的示例。它也适用于您正在转换的 Delphi 代码的转换...

object 是 C# 中最接近变体的东西。

0
投票

你可以制作一个“普通”数组......

MyType[] Line = new MyType[2];

或通用列表....

List<MyType> Line = new List<MyType>(); // list is empty, still have to add n elements
Line.Add( new MyType() );
Line.Add( new MyType() );

你走哪条路取决于你的需要。如果您需要一个在程序运行时动态增长的“数组”，请使用通用列表。如果没有，请使用数组。

现在，要记住的是，其中任何一个都是基于 0 的——而不是像 Delphi 那样任意从 N 开始。

现在，如果需要，您可以使用 

HashTable
或 
Dictionary
来模拟。

最新问题
© www.soinside.com 2019 - 2024. All rights reserved.