在Aspose.Pdf for .Net使用中，為表單字段設置/更新默認字體，需要用到一個新的構造函數DefaultAppearance，這個新類存在Aspose.Pdf.InteractiveFeatures名稱空間之下。 為了使用這個新對象,將會用到Field class類的DefaultAppearance屬性。

C#

//open document
Document pdfDocument = new Document("input.pdf");
// get particular form field from document
Aspose.Pdf.InteractiveFeatures.Forms.Field field = pdfDocument.Form["textField"] as Aspose.Pdf.InteractiveFeatures.Forms.Field;
// create font object
Aspose.Pdf.Text.Font font = FontRepository.FindFont("ComicSansMS");
// set the font information for form field
field.DefaultAppearance = new Aspose.Pdf.InteractiveFeatures.DefaultAppearance(font, 10, System.Drawing.Color.Black);
//save updated document
pdfDocument.Save("output.pdf");

VB.NET

'open document
Dim pdfDocument As Document = New Document("input.pdf")
' get particular form field from document
Dim field As Aspose.Pdf.InteractiveFeatures.Forms.Field = TryCast(pdfDocument.Form("textField"), Aspose.Pdf.InteractiveFeatures.Forms.Field)
' create font object
Dim font As Aspose.Pdf.Text.Font = Aspose.Pdf.Text.FontRepository.FindFont("ComicSansMS")
' set the font information for form field
field.DefaultAppearance = New Aspose.Pdf.InteractiveFeatures.DefaultAppearance(font, 10, System.Drawing.Color.Black)
' save updated document
pdfDocument.Save("output.pdf")