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External JS for form data validation | VB.NET
Program.vb:
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