Activating a new Form at run-time (Visual F#)

To activate a new form at run-time, simply use the Show and Hide methods of the form. The following steps demonstrate a simple example:

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 3 again and this time, select System.Drawing from the .Net tab.

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

//use the F# standard library
open System
//use the drawing class
open System.Drawing 
//Specifies the memory location of the form class
open System.Windows.Forms 
//create a font object
let ffont=new Font("Arial",12.0f,FontStyle.Bold, GraphicsUnit.Point)
//creates a form named “firstform”
let firstform=new Form(Text="Display First Form",StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font,ClientSize=new System.Drawing.Size(200,200),FormBorderStyle=FormBorderStyle.FixedSingle)
//creates a label,sets its caption to “This is the first form”
let fformlabel=new Label(Text="This is the first form",AutoSize=true)
//make a button,sets its caption to Second Form
let nxtbutton=new Button(Text="Second Form", Location=new System.Drawing.Point(100, 200),AutoSize=true)
//creates another button, set its text to exit
let fexitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 200),AutoSize=true)
//adds the controls we made to the first form
firstform.Controls.Add(fformlabel)
//applies font format to our label
fformlabel.Font<-ffont
firstform.Controls.Add(nxtbutton)
firstform.Controls.Add(fexitbutton)
//when the “Second Form” button of the first form is clicked
nxtbutton.Click.Add(fun nxtform->
//hides the first form
firstform.Hide()
//create a new form named secondform
let secondform=new Form(Text="Second Form", StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font,ClientSize=new System.Drawing.Size(200,200),FormBorderStyle=FormBorderStyle.FixedSingle)
//create a label and sets its caption to “This is the second form”
let sformlabel=new Label(Text="This is the second form",AutoSize=true)
//creates a button and sets its text to “First Form”
let prevbutton=new Button(Text="First Form", Location=new System.Drawing.Point(100, 200))
//adds a button, set its text to “Exit”
let sexitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 200))
//show the second form
secondform.Show()
//add the controls we made on the second form
secondform.Controls.Add(sformlabel)
//applies font format to our label
sformlabel.Font<-ffont
secondform.Controls.Add(prevbutton)
secondform.Controls.Add(sexitbutton)
//when the “First Form” button of the second form is clicked
prevbutton.Click.Add(fun prevform->
//show the first form
firstform.Show()
//hide the second form
secondform.Hide())
//when the exit button of the second form is clicked
sexitbutton.Click.Add(fun quit->
//close the first form
firstform.Close()
//close the second form
secondform.Close()))
//when the exit button of the first form is clicked
//close the first form
fexitbutton.Click.Add(fun quit->firstform.Close())                     
firstform.Show()
//executes our application
Application.Run(firstform)

Here is our sample code again and this time comments omitted.

open System
open System.Drawing  
open System.Windows.Forms
let ffont=new Font("Arial",12.0f,FontStyle.Bold, , GraphicsUnit.Point) 
let firstform=new Form(Text="First Form", StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font,ClientSize=new System.Drawing.Size(200,200),FormBorderStyle=FormBorderStyle.FixedSingle)
let fformlabel=new Label(Text="This is the first form",AutoSize=true)
let nxtbutton=new Button(Text="Second Form", Location=new System.Drawing.Point(100, 200),AutoSize=true)
let fexitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 200),AutoSize=true)
firstform.Controls.Add(fformlabel)
fformlabel.Font<-ffont
firstform.Controls.Add(nxtbutton)
firstform.Controls.Add(fexitbutton)

nxtbutton.Click.Add(fun nxtform->
firstform.Hide()
let secondform=new Form(Text="Second Form", StartPosition=FormStartPosition.CenterScreen,AutoScaleMode=AutoScaleMode.Font,ClientSize=new System.Drawing.Size(200,200),FormBorderStyle=FormBorderStyle.FixedSingle)
let sformlabel=new Label(Text="This is the second form",AutoSize=true)
let prevbutton=new Button(Text="First Form", Location=new System.Drawing.Point(100, 200))
let sexitbutton=new Button(Text="Exit", Location=new System.Drawing.Point(200, 200))
secondform.Show()
secondform.Controls.Add(sformlabel)
sformlabel.Font<-ffont
secondform.Controls.Add(prevbutton)
secondform.Controls.Add(sexitbutton)
prevbutton.Click.Add(fun prevform->
firstform.Show()
secondform.Hide())
sexitbutton.Click.Add(fun quit->
firstform.Close()
secondform.Close()))  

fexitbutton.Click.Add(fun quit->firstform.Close())                     
firstform.Show()
Application.Run(firstform)

5. Click the run icon to execute your application. You should now see an output similar to the following screen shot: