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()