In the previous lesson, we have learned how to create Graphics and the Pen objects to draw straight lines in Visual Basic 2015. Now we shall learn how to draw rectangles.
There are two methods to draw a rectangle on the form in Visual Basic 2015:
Draw a rectangle directly using the DrawRectangle method by specifying its upper-left corner’s coordinate and its width and height. You also need to create a Graphics and a Pen object to handle the actual drawing. The method of the Graphics object to draw the rectangle is DrawRectangle.The syntax is:
myGrapphics.DrawRectangle(myPen, X, Y, width, height)
*myGraphics is the variable name of the Graphics object and myPen is the variable name of the Pen object created by you. You can use any valid and meaningful variable names. X, Y is the coordinate of the upper left corner of the rectangle while width and height are self-explanatory, i.e, the width and height of the rectangle.
Dim myPen As Pen myPen = New Pen(Drawing.Color.Blue, 5) Dim myGraphics As Graphics = Me.CreateGraphics myGraphics.DrawRectangle(myPen, 0, 0, 100, 50)
The second method is to create a rectangle object first and then draw this rectangle using the DrawRectangle method. The syntax is as shown below:
where myRectangle is the rectangle object created by you, the user.
The code to create a rectangle object is as shown below:
Dim myRectangle As New Rectangle myRect.X = 10 myRect.Y = 10 myRect.Width = 100 myRect.Height = 50
You can also create a rectangle object using a one-line code as follows:
Dim myRectangle As New Rectangle(X,Y,width, height)
and the code to draw the above rectangle is
The shape we draw so far are drawn with a solid line, we can actually customize the line style of the Pen object so that we have dotted line, a line consisting of dashes and more. For example, the syntax to draw the dotted line is shown below:
Where the last argument Dot specifies a particular line DashStyle value, a line that makes up of dots here. Other DashStyles values are Dash, DashDot, DashDotDot and Solid.The following code draws a rectangle with the blue dotted line.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click Dim myPen As Pen myPen = New Pen(Drawing.Color.Blue, 5) Dim myGraphics As Graphics = Me.CreateGraphics myPen.DashStyle = Drawing.Drawing2D.DashStyle.Dot myGraphics.DrawRectangle(myPen, 10, 10, 100, 50) End Sub
The output image is as shown in Figure 27.1