External JS for form data validation - VB.NET
PDF SDK sample in VB.NET demonstrating ‘External JS for form data validation’
Program.vb
Imports Bytescout.PDF
''' <summary>
''' This example demonstrates validation of form with JavaScript
''' </summary>
Class Program
Shared Sub Main()
' Create new document
Dim pdfDocument = New Document()
pdfDocument.RegistrationName = "demo"
pdfDocument.RegistrationKey = "demo"
' If you wish to load an existing document uncomment the line below And comment the Add page section instead
' pdfDocument.Load(".\existing_document.pdf")
' Add page
Dim page As New Page(PaperFormat.A4)
pdfDocument.Pages.Add(page)
' Get page canvas
Dim canvas As Canvas = page.Canvas
' Prepare font and brush
Dim font As Font = New Font(StandardFonts.Helvetica, 15)
Dim blackBrush As New SolidBrush()
' Draw First Name Label
canvas.DrawString("First Name: ", font, blackBrush, 50, 50)
' Create FirstName EditBox
Dim firstName As EditBox = New EditBox(130, 50, 100, 30, "FirstName")
' Add javascript validation on focus lose
firstName.OnLoseFocus = New JavaScriptAction("
if(event.value == ''){
app.alert('First Name is required!');
}
")
' Add First Name EditBox to page
page.Annotations.Add(firstName)
' Draw Last Name Label
canvas.DrawString("Last Name: ", font, blackBrush, 50, 100)
' Create Last Name EditBox
Dim lastName As EditBox = New EditBox(130, 100, 100, 30, "LastName")
' Add javascript validation on focus lose
lastName.OnLoseFocus = New JavaScriptAction("
if(event.value == ''){
app.alert('Last Name is required!');
}
")
page.Annotations.Add(lastName)
' Create a button
Dim btnSubmit As PushButton = New PushButton(50, 150, 150, 30, "SayHello")
btnSubmit.Caption = "Say Hello!"
' Javascript action to validate as well as displaying message
btnSubmit.OnMouseDown = New JavaScriptAction("
var valFirstName = this.getField('FirstName').value;
var valLastName = this.getField('LastName').value;
if(valFirstName == '' || valLastName == ''){
app.alert('Please complete incompete values in form!');
}
else{
var messageToDisplay = 'Hello, ' + valLastName + ' ' + valFirstName + '!';
app.alert(messageToDisplay, 4);
}
")
page.Annotations.Add(btnSubmit)
' Save document to file
pdfDocument.Save("result.pdf")
' Cleanup
pdfDocument.Dispose()
' Open document in default PDF viewer app
Process.Start("result.pdf")
End Sub
End Class