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Delphi to C # question

I have a Delphi program that I have to convert to C #. I did most of the conversion, but ran into several problems with VarArrayCreate.

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

I can not imagine how to convert or replace VarArrayCreate. I know that an object in C # can be used to replace Variant, but above, I'm stuck.

any help would be great.

I have added the Delphi code below. I'm interested in the procedure "TForm1.Button3Click (Sender: TObject); procedure:

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.

Mike

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4 answers

you can make an "ordinary" array ....

 MyType[] Line = new MyType[2];

or a general list ....

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

how you go depends on what you need. If you need an "array" that grows dynamically while your program is running, go to the general list. if not, go to the array.

Now you need to keep in mind that either one of them is based on 0, and not arbitrarily, starting with N, as Delphi does.

you can now simulate this with a HashTable or Dictionary if you need to.

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Calling VarArrayCreate in your example creates an array of 2 elements, starting at index zero and ending at index 1.

The C # equivalent would be as follows:

 object[] Line; Line = new object[2];
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It should be noted that varArray creates an array of variant data type, which is very different from ordinary types. It creates a structure in memory that cannot be compared with an instance of an object (AFAIK). It is expected that it will be saved as a list of nodes with a binding (by pointer). However, the structure of the Delphi variant is identical to the Microsoft storage format, which means you can call winapi to achieve the same.

If you haven't solved this yet, I would take a look at the COM support libraries inside .NET. Perhaps in the section "System.Runtime.InteropServices". Or look at the options.pas block in Delphi and see what WinAPI functions they call.

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 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); }

Above is an example of the ShowPoints method from Alex VB code. It will also apply to the conversion of the Delphi code that you convert ...

the object is closest to the option in C #.

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Source: https://habr.com/ru/post/1332426/

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