前面我们介绍了如何使用Spire.PDF 创建PDF表单域 及 重置表单域字段的值，该文将详细介绍如何使用Spire.PDF读取PDF表单域及获取域里面的值。

读取PDF表单域

//创建PdfDocument实例并加载示例文档
PdfDocument pdf = new PdfDocument();
pdf.LoadFromFile("Sample.pdf");

//遍历FieldsWidget.List获取所有表单域，并打印出表单域名称
PdfFormWidget formWidget = pdf.Form as PdfFormWidget;
for (int i = 0; i < formWidget.FieldsWidget.List.Count; i++)
{
    PdfField field = formWidget.FieldsWidget.List[i] as PdfField;
    string fieldName = field.Name;
    Console.WriteLine(fieldName);
}
Console.WriteLine("--------------------------------------");

//遍历FieldsWidget.List获取所有表单域，并打印出导出Value为YES的表单域名称
List<PdfField> list = formWidget.FieldsWidget.GetFieldsByExportValue("Yes");

for (int i = 0; i < list.Count; i++)
{
    string fieldName = list[i].Name;
    Console.WriteLine(fieldName);
}
Console.Read();

'创建PdfDocument实例并加载示例文档 Dim pdf As New PdfDocument() pdf.LoadFromFile("Sample.pdf") '遍历FieldsWidget.List获取所有表单域，并打印出表单域名称
Dim formWidget As PdfFormWidget = TryCast(pdf.Form, PdfFormWidget)
For i As Integer = 0 To formWidget.FieldsWidget.List.Count - 1
	Dim field As PdfField = TryCast(formWidget.FieldsWidget.List(i), PdfField)
	Dim fieldName As String = field.Name
	Console.WriteLine(fieldName)
Next
Console.WriteLine("--------------------------------------")

'遍历FieldsWidget.List获取所有表单域，并打印出导出Value为YES的表单域名称 Dim list As List(Of PdfField) = formWidget.FieldsWidget.GetFieldsByExportValue("Yes") For i As Integer = 0 To list.Count - 1 Dim fieldName As String = list(i).Name Console.WriteLine(fieldName) Next Console.Read()

读取域里面选择的值：

//创建PdfDocument实例并加载示例文档 PdfDocument pdf = new PdfDocument();pdf.LoadFromFile("Sample.pdf");//获取PDF文档第一页 PdfPageBase page = pdf.Pages[0];//遍历FieldsWidget.List获取所有表单域 PdfFormWidget formWidget = pdf.Form as PdfFormWidget;for (int i = 0;i < formWidget.FieldsWidget.List.Count;i++){PdfField field = formWidget.FieldsWidget.List[i] as PdfField;//获取单选钮表单域并输出所选择的按钮值 if (field is PdfRadioButtonListFieldWidget){PdfRadioButtonListFieldWidget radioButton = field as PdfRadioButtonListFieldWidget;foreach (PdfRadioButtonWidgetItem item in radioButton.WidgetItems){if (item.Selected){Console.WriteLine(item.Value);}}}}Console.ReadKey();

'创建PdfDocument实例并加载示例文档
Dim pdf As New PdfDocument()
pdf.LoadFromFile("Sample.pdf")

'获取PDF文档第一页 Dim page As PdfPageBase = pdf.Pages(0) '遍历FieldsWidget.List获取所有表单域
Dim formWidget As PdfFormWidget = TryCast(pdf.Form, PdfFormWidget)

For i As Integer = 0 To formWidget.FieldsWidget.List.Count - 1
	Dim field As PdfField = TryCast(formWidget.FieldsWidget.List(i), PdfField)

	'获取单选钮表单域并输出所选择的按钮值 If TypeOf field Is PdfRadioButtonListFieldWidget Then Dim radioButton As PdfRadioButtonListFieldWidget = TryCast(field,PdfRadioButtonListFieldWidget) For Each item As PdfRadioButtonWidgetItem In radioButton.WidgetItems If item.Selected Then Console.WriteLine(item.Value) End If Next End If Next Console.ReadKey()