Aspose.PDF for .NET是一種高PDF處理和解析API，用于在跨平臺應用程序中執行文檔管理和操作任務。API可以輕松用于生成、修改、轉換、渲染、保護和打印PDF文檔，而無需使用Adobe Acrobat。此外，API還提供PDF壓縮選項，表格創建和操作，圖形和圖像功能，廣泛的超鏈接功能，印章和水印任務，擴展的安全控制和自定義字體處理。

在接下來的系列教程中，將為開發者帶來Aspose.PDF for .NET的一系列使用教程，例如進行文檔間的轉換，如何標記PDF文件，如何使用表單和圖表等等。本文將介紹如何在PDF文檔中添加、修改和刪除表單字段。

>>Aspose.PDF for .NET更新至最新版v20.7，歡迎下載體驗。

在PDF文檔中添加表單字段

要添加表單字段：

• 創建您要添加的表單字段。
• 調用Form集合的Add方法。

添加TextBoxField

以下示例顯示了如何添加TextBoxField。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Open document
Document pdfDocument = new Document(dataDir + "TextField.pdf");

// Create a field
TextBoxField textBoxField = new TextBoxField(pdfDocument.Pages[1], new Aspose.Pdf.Rectangle(100, 200, 300, 300));
textBoxField.PartialName = "textbox1";
textBoxField.Value = "Text Box";

// TextBoxField.Border = new Border(
Border border = new Border(textBoxField);
border.Width = 5;
border.Dash = new Dash(1, 1);
textBoxField.Border = border;

textBoxField.Color = Aspose.Pdf.Color.FromRgb(System.Drawing.Color.Green);

// Add field to the document
pdfDocument.Form.Add(textBoxField, 1);

dataDir = dataDir + "TextBox_out.pdf";
// Save modified PDF
pdfDocument.Save(dataDir);

添加RadioButtonField

以下代碼段顯示了使用三個選項添加RadioButtonField并將其放置在Table單元格中的步驟。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Instantiate Document object
Document pdfDocument = new Document();
// Add a page to PDF file
pdfDocument.Pages.Add();
// Instatiate RadioButtonField object with page number as argument
RadioButtonField radio = new RadioButtonField(pdfDocument.Pages[1]);
// Add first radio button option and also specify its origin using Rectangle object
radio.AddOption("Test", new Rectangle(0, 0, 20, 20));
// Add second radio button option
radio.AddOption("Test1", new Rectangle(20, 20, 40, 40));
// Add radio button to form object of Document object
pdfDocument.Form.Add(radio);

dataDir = dataDir + "RadioButton_out.pdf";
// Save the PDF file
pdfDocument.Save(dataDir);

以下代碼段顯示了如何在PDF文檔中添加RadioButtonField。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

Document doc = new Document();
Page page = doc.Pages.Add();
Aspose.Pdf.Table table = new Aspose.Pdf.Table();
table.ColumnWidths = "120 120 120";
page.Paragraphs.Add(table);
Row r1 = table.Rows.Add();
Cell c1 = r1.Cells.Add();
Cell c2 = r1.Cells.Add();
Cell c3 = r1.Cells.Add();

RadioButtonField rf = new RadioButtonField(page);
rf.PartialName = "radio";
doc.Form.Add(rf, 1);

RadioButtonOptionField opt1 = new RadioButtonOptionField();
RadioButtonOptionField opt2 = new RadioButtonOptionField();
RadioButtonOptionField opt3 = new RadioButtonOptionField();

opt1.OptionName = "Item1";
opt2.OptionName = "Item2";
opt3.OptionName = "Item3";

opt1.Width = 15;
opt1.Height = 15;
opt2.Width = 15;
opt2.Height = 15;
opt3.Width = 15;
opt3.Height = 15;

rf.Add(opt1);
rf.Add(opt2);
rf.Add(opt3);

opt1.Border = new Border(opt1);
opt1.Border.Width = 1;
opt1.Border.Style = BorderStyle.Solid;
opt1.Characteristics.Border = System.Drawing.Color.Black;
opt1.DefaultAppearance.TextColor = System.Drawing.Color.Red;
opt1.Caption = new TextFragment("Item1");
opt2.Border = new Border(opt1);
opt2.Border.Width = 1;
opt2.Border.Style = BorderStyle.Solid;
opt2.Characteristics.Border = System.Drawing.Color.Black;
opt2.DefaultAppearance.TextColor = System.Drawing.Color.Red;
opt2.Caption = new TextFragment("Item2");
opt3.Border = new Border(opt1);
opt3.Border.Width = 1;
opt3.Border.Style = BorderStyle.Solid;
opt3.Characteristics.Border = System.Drawing.Color.Black;
opt3.DefaultAppearance.TextColor = System.Drawing.Color.Red;
opt3.Caption = new TextFragment("Item3");
c1.Paragraphs.Add(opt1);
c2.Paragraphs.Add(opt2);
c3.Paragraphs.Add(opt3);

dataDir = dataDir + "RadioButtonWithOptions_out.pdf";
// Save the PDF file
doc.Save(dataDir);

為RadioButtonField添加標題

以下代碼段顯示了如何添加與RadioButtonField關聯的標題：

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Load source PDF form
Aspose.Pdf.Facades.Form form1 = new Aspose.Pdf.Facades.Form(dataDir + "RadioButtonField.pdf");
Document PDF_Template_PDF_HTML = new Document(dataDir + "RadioButtonField.pdf");
foreach (var item in form1.FieldNames)
{
    Console.WriteLine(item.ToString());
    Dictionary radioOptions = form1.GetButtonOptionValues(item);
    if (item.Contains("radio1"))
    {
        Aspose.Pdf.Forms.RadioButtonField field0 = PDF_Template_PDF_HTML.Form[item] as Aspose.Pdf.Forms.RadioButtonField;
        Aspose.Pdf.Forms.RadioButtonOptionField fieldoption = new Aspose.Pdf.Forms.RadioButtonOptionField();
        fieldoption.OptionName = "Yes";
        fieldoption.PartialName = "Yesname";

        var updatedFragment = new Aspose.Pdf.Text.TextFragment("test123");
        updatedFragment.TextState.Font = FontRepository.FindFont("Arial");
        updatedFragment.TextState.FontSize = 10;
        updatedFragment.TextState.LineSpacing = 6.32f;

        // Create TextParagraph object
        TextParagraph par = new TextParagraph();

        // Set paragraph position
        par.Position = new Position(field0.Rect.LLX, field0.Rect.LLY + updatedFragment.TextState.FontSize);
        // Specify word wraping mode
        par.FormattingOptions.WrapMode = TextFormattingOptions.WordWrapMode.ByWords;

        // Add new TextFragment to paragraph
        par.AppendLine(updatedFragment);

        // Add the TextParagraph using TextBuilder
        TextBuilder textBuilder = new TextBuilder(PDF_Template_PDF_HTML.Pages[1]);
        textBuilder.AppendParagraph(par);

        field0.DeleteOption("item1");
    }
}
PDF_Template_PDF_HTML.Save(dataDir + "RadioButtonField_out.pdf");

添加組合框字段

以下代碼段顯示了如何在PDF文檔中添加ComboBox字段。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Create Document object
Document doc = new Document();

// Add page to document object
doc.Pages.Add();

// Instantiate ComboBox Field object
ComboBoxField combo = new ComboBoxField(doc.Pages[1], new Aspose.Pdf.Rectangle(100, 600, 150, 616));

// Add option to ComboBox
combo.AddOption("Red");
combo.AddOption("Yellow");
combo.AddOption("Green");
combo.AddOption("Blue");

// Add combo box object to form fields collection of document object
doc.Form.Add(combo);
dataDir = dataDir + "ComboBox_out.pdf";
// Save the PDF document
doc.Save(dataDir);

修改PDF文檔中的表單字段

要修改現有的表單字段，您可以從Form集合中獲取該字段并設置其屬性。然后保存更新的PDF文檔。以下代碼段顯示了如何修改PDF文檔中的現有表單字段。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Open document
Document pdfDocument = new Document(dataDir + "ModifyFormField.pdf");

// Get a field
TextBoxField textBoxField = pdfDocument.Form["textbox1"] as TextBoxField;

// Modify field value
textBoxField.Value = "New Value";
textBoxField.ReadOnly = true;
dataDir = dataDir + "ModifyFormField_out.pdf";
// Save updated document
pdfDocument.Save(dataDir);

從PDF文檔中刪除特殊表格字段

所有表單字段都包含在Document對象的Form集合中。該集合提供了管理表單字段的不同方法，包括該Delete方法。如果要刪除特定字段，請將字段名稱作為參數傳遞給Delete方法，然后保存更新的PDF文檔。以下代碼段顯示了如何從PDF文檔中刪除特定字段。

// The path to the documents directory.
string dataDir = RunExamples.GetDataDir_AsposePdf_Forms();

// Open document
Document pdfDocument = new Document(dataDir + "DeleteFormField.pdf");

// Delete a particular field by name
pdfDocument.Form.Delete("textbox1");
dataDir = dataDir + "DeleteFormField_out.pdf";
// Save modified document
pdfDocument.Save(dataDir);