Learn more about MATLAB Builder NE

Simple Plot Example

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Purpose Procedure

Purpose

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

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Procedure

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

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

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

   2. At the MATLAB command prompt, change folder to the new PlotExample\PlotComp subfolder in your work folder.

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

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

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

   deploytool

4. Build the .NET component. See the instructions in Building Your Component for more details. Use the following information:

   Project Name	PlotComp
   Class Name	Plotter
   File to compile	drawplot.m

5. 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;
   
   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.

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

   1. The PlotCSApp folder 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. Add a reference to the MWArray component, which is matlabroot\toolbox\dotnetbuilder\bin\architecture\framework_version
      \mwarray.dll.

   3. Add or, if necessary, 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 subfolder of your work area.)

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

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Sample Applications (C#)

Passing Variable Arguments

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