How can I fill PDF form in VB.NET or C#?

Q:

How do I fill PDF form using PDFNet SDK in VB.NET?
I am looking for someting very simple to use.
----
A:

You can use PDFNet SDK to programmatically fill-in PDF forms as
illustrated in
InteractiveForms (http://www.pdftron.com/net/
samplecode.html#InteractiveForms) and FDF (http://www.pdftron.com/net/
samplecode.html#FDF) sample projects. The following example sets the
new value for "MemberName":

Imports System
Imports pdftron
Imports pdftron.Common
Imports pdftron.SDF
Imports pdftron.PDF

Module Module1

    Sub SetFieldValue(ByRef d As PDFDoc, ByVal name As String, ByVal
value As String)
        Dim itr As FieldIterator = d.FieldFind(name)
        If Not itr.Equals(d.FieldEnd()) Then
            Dim field As Field = itr.Current()
            ' Console.WriteLine("Field search for {0} was
successful.", field.GetName())
            field.SetValue(Obj.CreateString(value)) ' Set the value
        Else
            ' Console.WriteLine("'{0}' not found.", value)
        End If
    End Sub

    Sub Main()

        PDFNet.Initialize()
        PDFNet.SetResourcesPath("../../../../resources")

        Try
            Dim doc4 As PDFDoc = New PDFDoc("Test.pdf")
            doc4.InitSecurityHandler()

            SetFieldValue(doc4, "MemberName", "My Name")

            doc4.RefreshFieldAppearances()
            doc4.Save("Test2.pdf", 0)
            doc4.Close()

            Console.WriteLine("Done.")
        Catch ex As PDFNetException
            Console.WriteLine(ex.Message)
        Catch ex As Exception
            MsgBox(ex.Message)
        End Try

        PDFNet.Terminate()

    End Sub
End Module

You can set the field value in C# along the same lines. For example:

FieldIterator itr = pdfdoc.FieldFind("name");
if (itr != pdfdoc.FieldEnd()) {
  Field field = itr.Current();
  field.SetValue(Obj.CreateString("John Doe"));
}