Add Two Numbers (Visual F# Windows Forms Application)

I’d been desperately combing the net for a while now looking for some tutorials relating to simple computations in Visual F# Windows Forms Application unfortunately I got no fluke finding some so I decided to make one. Today we will be making a simple application that adds two numbers and I hope that this will give you a head start in building advanced application using F# Windows Forms.
To create an application that adds two numbers, follow these simple steps:

1. Click Start>All Programs>Microsoft Visual Studio 2008>Microsoft Visual Studio 2008.

2. Click File>New>Project>Select Visual F# in the project types>Select F# application in the Visual Studio installed templates category.

3. Click the Project menu>Add reference>Click the .Net tab>Locate then double-click System.Windows.Forms.
Do step number 3 again and this time,select System.Drawing

4. Enter the following code after the line “// Learn more about F# at http://fsharp.net “:

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1. // Learn more about F# at http://fsharp.net  
2. //uses the F# standard library  
3. open System  
4. //specifies the location of the Drawing classes  
5. open System.Drawing  
6. //specifies the namespace memory location of the form class  
7. open System.Windows.Forms  
8. //creates a new form  
9. let addform=new Form(Text="Add Numbers", Size=new System.Drawing.Size(300, 200),StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font)  
10. //creates a label  
11. let n1label=new Label(Text="First number:",Top=20,Left=5,AutoSize=true)  
12. let firsttextbox=new TextBox(Location=new System.Drawing.Point(80, 20))  
13. //creates another label and change its text to “Second number:”  
14. let n2label=new Label(Text="Second number:", Location=new System.Drawing.Point(0,50),AutoSize=true)  
15. let secondtextbox=new TextBox(Location=new System.Drawing.Point(100,50))  
16. //creates another label and change its text to sum  
17. let n3label=new Label(Text="Sum:", Location=new System.Drawing.Point(0, 90),AutoSize=true)  
18. //creates a label that will display the result of the computation  
19. let anslabel=new Label(Location=new System.Drawing.Point(80, 90))  
20. //make our buttons  
21. let addbutton=new Button(Text="Add", Location=new System.Drawing.Point(100, 130))  
22. let exitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 130))  
23. //add the controls into the form  
24. addform.Controls.Add(n1label)  
25. addform.Controls.Add(firsttextbox)  
26. addform.Controls.Add(n2label)  
27. addform.Controls.Add(secondtextbox)  
28. addform.Controls.Add(n3label)  
29. addform.Controls.Add(anslabel)  
30. addform.Controls.Add(addbutton)  
31. addform.Controls.Add(exitbutton)  
32.   
33. //when the add button is clicked  
34. addbutton.Click.Add(fun addfunction ->  
35. //convert the textbox values to unsigned int  
36. let firstnum=Convert.ToUInt32(firsttextbox.Text)  
37. let secondnum=Convert.ToUInt32(secondtextbox.Text)  
38. let sumval=firstnum + secondnum  
39. //display the sum in the anslabel  
40. anslabel.Text<-Convert.ToString(sumval))  
41.  //when the exit button is clicked, close the form              
42. exitbutton.Click.Add(fun exit -> addform.Close())    
43. addform.Show()  
44. Application.Run(addform)  

// Learn more about F# at http://fsharp.net
//uses the F# standard library
open System
//specifies the location of the Drawing classes
open System.Drawing
//specifies the namespace memory location of the form class
open System.Windows.Forms
//creates a new form
let addform=new Form(Text="Add Numbers", Size=new System.Drawing.Size(300, 200),StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font)
//creates a label
let n1label=new Label(Text="First number:",Top=20,Left=5,AutoSize=true)
let firsttextbox=new TextBox(Location=new System.Drawing.Point(80, 20))
//creates another label and change its text to “Second number:”
let n2label=new Label(Text="Second number:", Location=new System.Drawing.Point(0,50),AutoSize=true)
let secondtextbox=new TextBox(Location=new System.Drawing.Point(100,50))
//creates another label and change its text to sum
let n3label=new Label(Text="Sum:", Location=new System.Drawing.Point(0, 90),AutoSize=true)
//creates a label that will display the result of the computation
let anslabel=new Label(Location=new System.Drawing.Point(80, 90))
//make our buttons
let addbutton=new Button(Text="Add", Location=new System.Drawing.Point(100, 130))
let exitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 130))
//add the controls into the form
addform.Controls.Add(n1label)
addform.Controls.Add(firsttextbox)
addform.Controls.Add(n2label)
addform.Controls.Add(secondtextbox)
addform.Controls.Add(n3label)
addform.Controls.Add(anslabel)
addform.Controls.Add(addbutton)
addform.Controls.Add(exitbutton)

//when the add button is clicked
addbutton.Click.Add(fun addfunction ->
//convert the textbox values to unsigned int
let firstnum=Convert.ToUInt32(firsttextbox.Text)
let secondnum=Convert.ToUInt32(secondtextbox.Text)
let sumval=firstnum + secondnum
//display the sum in the anslabel
anslabel.Text<-Convert.ToString(sumval))
 //when the exit button is clicked, close the form            
exitbutton.Click.Add(fun exit -> addform.Close())  
addform.Show()
Application.Run(addform)

6. Press Ctrl+F5 or click the run icon to execute your application. You should now see something similar to the screenshot below:



7. That's all. Enjoy programming!