MATLAB® Builder™ NE

Simple Plot Example

The drawgraph function displays a plot of input parameters x and y.

Purpose

The purpose of the example is to show you how to:

• Use the MATLAB Builder NE product to convert a MATLAB function (drawgraph) to a method of a .NET class (Plotter) and wrap the class in a .NET component (PlotComp).

• Access the component in a C# application (PlotApp.cs) by instantiating the Plotter class and using the MWArray class library to handle data conversion.

  Note   For complete reference information about the MWArray class hierarchy, see the MWArray Class Library Reference (available online only).

• Build and run the PlotCSApp application, using the Visual Studio .NET development environment.

Back to Top

Procedure

1. If you have not already done so, copy the files for this example as follows:

   1. Copy the following directory that ships with the MATLAB product to your work directory:

      matlabroot\toolbox\dotnetbuilder\Examples\VS8\NET\PlotExample

   2. At the MATLAB command prompt, cd to the new PlotExample\PlotComp subdirectory in your work directory.

2. Write the drawgraph function as you would any MATLAB function.

   This code is already in your work directory in PlotExample\PlotComp\drawgraph.m.

3. While in MATLAB, issue the following command to open the Deployment Tool window:

   deploytool

4. In MATLAB, Select File > New Deployment Project.

5. In the New Deployment Project dialog box, select MATLAB Builder NE and .NET Component.

6. Select PlotComp as the name of the project and click OK.

7. In the Deployment Tool, select PlotComp.class and right-click. Select Rename and type Plotter.

8. Select Generate Verbose Output.

9. Add the drawplot.m file to the project.

10. Save the project.

11. Build the component by clicking the button in the Deployment Tool toolbar.

    The build process begins, and a log of the build appears in the Output pane of the Deployment Tool. The files that are needed for the component are copied to two newly created subdirectories, src and distrib, under the PlotComp directory. A copy of the build log is placed in the src directory.

    See What Happens in the Build Process? for more information.

12. Write source code for a C# application that accesses the component.

    The sample application for this example is in matlabroot\toolbox\dotnetbuilder\Examples\VS8\PlotExample
    \PlotCSApp\PlotApp.cs.

    The program listing is shown here.

     PlotApp.cs

    // *******************************************************************************
    //
    // PlotApp.cs
    //
    // This example demonstrates how to use MATLAB Builder NE to build a component 
    // that displays a MATLAB figure window.
    //
    // Copyright 2001-2008 The MathWorks, Inc.
    //
    // *******************************************************************************
    
    using System;
    
    using MathWorks.MATLAB.NET.Utility;
    using MathWorks.MATLAB.NET.Arrays;
    
    using PlotComp;
    
    [assembly: NativeGC(true, GCBlockSize= 25)]  // Set native memory management block size to 25 MB.
    
    namespace MathWorks.Examples.PlotApp
     {
      /// <summary>
      /// This application demonstrates plotting x-y data by graphing a simple 
      /// parabola into a MATLAB figure window. 
      /// </summary>
      class PlotCSApp
        {
          #region MAIN
    
          /// <summary>
          /// The main entry point for the application.
          /// </summary>
          [STAThread]
          static void Main(string[] args)
            {
              try
                {
                  const int numPoints= 10;  // Number of points to plot
    
                  // Allocate native array for plot values
                  double [,] plotValues= new double[2, numPoints];
    
                  // Plot 5x vs x^2
                  for (int x= 1; x <= numPoints; x++)
                    {
                      plotValues[0, x-1]= x*5;
                      plotValues[1, x-1]= x*x;
                    }
    
                  // Create a new plotter object
                  Plotter plotter= new Plotter();
    
                  // Plot the two sets of values - Note the ability to cast the native array to a MATLAB numeric array
                  plotter.drawgraph((MWNumericArray)plotValues);
    
                  Console.ReadLine();  // Wait for user to exit application
                }
    
              catch(Exception exception)
                {
                  Console.WriteLine("Error: {0}", exception);
                }
            }
    
          #endregion
        }
      }
    
      
    
    
    

    The program does the following:

    • Creates two arrays of double values

    • Creates a Plotter object.

    • Calls the drawgraph method to plot the equation using the MATLAB plot function.

    • Uses MWNumericArray to represent the data needed by the drawgraph method to plot the equation.

    • Uses a try-catch block to catch and handle any exceptions.

    The statement

     Plotter plotter= new Plotter(); 

    creates an instance of the Plotter class, and the statement

    plotter.drawgraph((MWNumericArray)plotValues);
    

    explicitly casts the native plotValues to MWNumericArray and then calls the method drawgraph.

13. Build the PlotCSApp application using Visual Studio .NET.

    1. The PlotCSApp directory contains a Visual Studio .NET project file for this example. Open the project in Visual Studio .NET by double-clicking PlotCSApp.csproj in Windows^® Explorer. You can also open it from the MATLAB desktop by right-clicking PlotCSApp.csproj > Open Outside MATLAB.

    2. If necessary, add a reference to the MWArray component, which is matlabroot\dotnetbuilder\bin\architecture\framework_version
       \mwarray.dll.

    3. If necessary, add (or fix the location of) a reference to the PlotComp component which you built in a previous step. (The component, PlotComp.dll, is in the \PlotExample\PlotComp\x86\V2.0\Debug\distrib subdirectory of your work area.)

14. Build and run the application in Visual Studio .NET.

Back to Top

Sample Applications (C#)

Passing Variable Arguments