This example uses a simple MATLAB® file that takes a single input and creates a magic square of that size. It then builds a COM component using this MATLAB file as a class method. Finally, the example shows the integration of this component into a standalone Microsoft® Visual Basic® application. The application accepts the magic square size as input and displays the matrix in a ListView control box.
ListView is a Windows® Form control that displays a list of items with icons. You can use a list view to create a user interface like the right pane of Windows Explorer. See the MSDN Library for more information about Windows Form controls.
To get started, create the MATLAB file mymagic.m
containing
the following code:
function y = mymagic(x)y = magic(x);
While in MATLAB, open the Library Compiler app.
Select Generic COM Component as the application type.
Add magicsquare.m
to the list of exported
functions.
magicsquare.m
is located in the MagicDemoComp
folder.
Click the Package button.
This procedure assumes that you are using Microsoft Visual Basic 6.0.
Start Visual Basic.
In the New Project dialog box, select Installed > Templates > Other Languages > Visual Basic > Windows Form Application as the project type and click Open. This creates a new Visual Basic project with a blank form.
From the main menu, select Project > References to open the Project References dialog box.
Select magicdemo 1.0 Type Library from the list of available components and click OK.
Returning to the Visual Basic main menu, select Project > Add Component... to open the Add New Item dialog box.
After you create the project, add a series of controls to the blank form to create a form with the following settings.
Control Type | Control Name | Properties | Purpose |
---|---|---|---|
|
| Caption = | Groups controls |
|
| Caption = | Labels the magic square edit box. |
|
| Accepts input of magic square size. | |
|
| Caption = | When pressed, creates a new magic square with current size. |
|
| GridLines = LabelEdit
= View = | Displays the magic square. |
When the form and controls are complete, add the following code to the form. This code references the control and variable names listed above. If you have given different names for any of the controls or any variable, change this code to reflect those differences.
Public Class magicvb Private sizeMatrix As Double 'Holds current matrix size Private theMagic As magicdemo.magicdemoclass 'magic object instance Private Sub magicvb_Load(sender As Object, e As EventArgs) Handles MyBase.Load 'This function is called when the form is loaded. 'Creates a new magic class instance. On Error GoTo Handle_Error theMagic = New magicdemo.magicdemoclass sizeMatrix = 0 Exit Sub Handle_Error: MsgBox(Err.Description) End Sub Private Sub ShowMatrix(matrixMagic As Object) 'This function populates the ListView with the contents of 'y. y is assumed to contain a 2D array. Dim szSquare As Long Dim indxRow As Long Dim indxCol As Long Dim nLen As Long On Error GoTo Handle_Error 'Get array size If IsArray(matrixMagic) Then szSquare = UBound(matrixMagic, 1) Else szSquare = 1 End If lstMagic.Clear() lstMagic.Columns.Add("") For cIndx = 1 To szSquare lstMagic.Columns.Add(CStr(cIndx)) Next lstMagic.View = View.Details For indxRow = 1 To szSquare Dim item As New ListViewItem(CStr(indxRow)) For indxCol = 1 To szSquare item.SubItems.Add(Format(matrixMagic(indxRow, indxCol))) Next lstMagic.Items.Add(item) Next Exit Sub Handle_Error: MsgBox(Err.Description) End Sub Private Sub btnCreate_Click(sender As Object, e As EventArgs) Handles btnCreate.Click 'This function is called when the Create button is pressed. 'Calls the mymagic method, and displays the magic square. Dim matrixMagic As Object If sizeMatrix <= 0 Or theMagic Is Nothing Then Exit Sub On Error GoTo Handle_Error Call theMagic.mymagic(1, matrixMagic, sizeMatrix) Call ShowMatrix(matrixMagic) Exit Sub Handle_Error: MsgBox(Err.Description) End Sub Private Sub edtSize_TextChanged(sender As Object, e As EventArgs) Handles edtSize.TextChanged 'This function is called when ever the contents of the 'Text box change. Sets the current value of Size. On Error Resume Next sizeMatrix = CDbl(edtSize.Text) If Err.Number > 0 Then sizeMatrix = 0 End If End Sub End Class
After the code is complete, create the standalone executable magic.exe
:
Reopen the project by selecting File > Save Project from the main
menu. Accept the default name for the main form and enter magic.vbp
for
the project name.
Return to the File menu. Select File > Make magic.exe to create the finished product.
You can run the magic.exe
executable as you
would any other program. When the main dialog box opens, enter a positive
number in the input box and click Create. A
magic square of the input size appears.
The ListView
control automatically implements
scrolling if the magic square is larger than 4-by-4.