使用 C# 和 AutoCAD COM API 进行 AutoCAD 2D 绘图

// Creating object reference to hold the reference of the circle to be created.
private AcadCircle Circle = default(AcadCircle);

// Creating object reference to hold the reference of running AutoCAD instance.
private AcadApplication AcadApp = default(AcadApplication);

private void btnCircle_Click(object sender, EventArgs e)
{
  // Getting running AutoCAD instance by Marshalling by passing Programmatic ID as a string, AutoCAD.Application is the Programmatic ID for AutoCAD.
  AcadApp = (AcadApplication)Marshal.GetActiveObject("AutoCAD.Application");

  // Now AcadApp has the reference to the running AutoCAD instance, AcadApp object acts as a port for accessing running instance of AutoCAD.

  // Syntax for creating circle in AutoCAD
  // AcadApp.ActiveDocument.ModelSpace.AddCircle(CenterOfCircle, RadiusOfCircle);
  //
  // AcadApp        - Reference to the running instance of AutoCAD.
  // ActiveDocument - Represents the current working drawing in AutoCAD.
  // ModelSpace     - Work Area in the current drawing.
  // AddCricle      - Method, which adds a circle to the modelspace of the current drawing using the CenterPoint and Radius.
  // CenterOfCircle - 3 Dimensional double array variable holds the center point of the circle in the X, Y and Z axis.
  // RadiusOfCircle - Double variable holds the radius of circle.

  // Definfing the center point for the circle, in this example, we are using origin(0,0,0) as the center of circle.
  double[] CenterOfCircle = new double[3];
  CenterOfCircle[0] = 0;
  CenterOfCircle[1] = 0;
  CenterOfCircle[2] = 0;

  // Defining radius of circle from the user input.
  double RadiusOfCircle = Convert.ToDouble(txtRadius.Text.Trim());

  // Adding Circle to the modelspace and getting reference to the circle created.
  Circle = AcadApp.ActiveDocument.ModelSpace.AddCircle(CenterOfCircle, RadiusOfCircle);
}

private void btnCaption_Click(object sender, EventArgs e)
{
  // Caption - AcadText object to hold the reference of the AcadText 
  AcadText Caption = default(AcadText);

  // Syntax for creating Text in AutoCAD
  // AcadApp.ActiveDocument.ModelSpace.AddText(TextString, InsertionPoint, Height);
  // 
  // AcadApp        - Reference to the running instance of AutoCAD.
  // ActiveDocument - Represents the current working drawing in AutoCAD.
  // ModelSpace     - Work Area in the current drawing.
  // AddText        - Method, which adds a Text to the modelspace of the current drawing using the TextString, InsertionPoint and Height.
  // TextString     - string, which represents the text to be written.
  // InsertionPoint - 3 Dimensional double array variable holds the insertion point of the circle in the X, Y and Z axis.
  // Height         - Double variable holds the height of text.

  // Text to be written just below the circle as a caption.
  string TextString = "CIRCLE";

  // Definfing the insertion point for the circle, in this example, we are going to place the text just below the circle.
  double[] InsertionPoint = new double[3];

  // Getting Centerpoint of circle we have created earlier to define the insertion point for the Caption.
  double[] CenterOfCircle = (double[])Circle.Center;

  InsertionPoint[0] = CenterOfCircle[0] - Circle.Radius / 2;
  InsertionPoint[1] = CenterOfCircle[1] - (Circle.Radius + 50);
  InsertionPoint[2] = 0;

  // Defining height of the text
  double Height = 20;
            
  // Adding text to the modelspace and getting reference to the text created.
  Caption = AcadApp.ActiveDocument.ModelSpace.AddText(TextString, InsertionPoint, Height);

  // Changing the text color
  Caption.color = ACAD_COLOR.acGreen;
}

private void btnDimension_Click(object sender, EventArgs e)
{
  // Dimension - AcadDimRadial object to hold the reference of the Radial Dimension of the circle
  AcadDimRadial Dimension = default(AcadDimRadial);

  // Syntax for creating Radial Dimension
  // AcadApp.ActiveDocument.ModelSpace.AddDimRadial(Center, ChordPoint, LeaderLength);
  // 
  // AcadApp        - Reference to the running instance of AutoCAD.
  // ActiveDocument - Represents the current working drawing in AutoCAD.
  // ModelSpace     - Work Area in the current drawing.
  // AddDimRadial   - Method, which adds Radial Dimension to the circle.
  // Center         - 3 Dimensional double array variable holds the center point of the circle in the X, Y and Z axis.
  // ChordPoint     - 3 Dimensional double array variable holds the Chord point of the circle in the X, Y and Z axis.
  // LeaderLength   - Double variable holds the length of the leader line.

  // Assigning Center point of the circle to the center point of radial dimension.
  double[] Center = Circle.Center;

  // Assigning Center Point of circle to ChordPoint
  double[] ChordPoint = Circle.Center;

  // Sets Leader line length
  double LeaderLength = 150;

  Dimension = AcadApp.ActiveDocument.ModelSpace.AddDimRadial(Center, ChordPoint, LeaderLength);

  // Sets the leader line caption
  Dimension.TextOverride = "R" + Circle.Radius.ToString();

  // Sets leader line caption color
  Dimension.TextColor = ACAD_COLOR.acCyan;

  // Sets leader line color
  Dimension.DimensionLineColor = ACAD_COLOR.acMagenta;

  // Sets leader line arrow head size
  Dimension.ArrowheadSize = 15;

  // Sets height of the caption of leader line
  Dimension.TextHeight = 15;
}