iTextSharp的。如何从AcroFields获取特定类型？像PushButtonField，RadioCheckField等 [英] iTextSharp. How to get specific types from AcroFields? Like PushButtonField, RadioCheckField, etc

问题描述

我正在尝试将 AcroFields 投射到特定类型，以便我可以设置它们的属性。

I am trying to cast AcroFields to the specific types so I can set properties on them.

我调用 AcroFields.GetField（字符串名称）; 我得到的只是一个字符串。

When I call AcroFields.GetField(string name); all I get is a string.

当我打电话给 AcroFields.GetFieldItem（字符串名称）; 我得到一个对象，但无法将其转换为特定类型。

When I call AcroFields.GetFieldItem(string name); I get an object but cannot cast it to the specific type.

我也有尝试：

AcroFields.SetFieldProperty（myfield，CheckType，RadioCheckField.TYPE_STAR，null）;

每次都返回false。

This returned false every time.

为了更好地解释我的情况：

To better explain my scenario:

我有一个现有的PDF（我没有生成这个文件）。

I have an existing PDF ( I am NOT generating this file ).

里面有一个复选框。我想像这样更改CheckType：
myRadioCheckField.CheckType = RadioCheckField.TYPE_STAR

There is a checkbox in it. I want to change the "CheckType" like this: myRadioCheckField.CheckType = RadioCheckField.TYPE_STAR

但是因为我无法将AcroField强制转换为特定类型我不能访问该属性CheckType。

But since I cannot cast the AcroField to the specific type I cannot access that property "CheckType".

有没有办法实现这个目标？

Is there a way to achieve this?

请提供工作样本如果可能的话。

Please provide a working sample if possible.

谢谢。

推荐答案

这是无法做到的。

据我所知iTextSharp不支持从AcroField转换回用于生成字段的原始类（RadioCheckField）。

As far as I know iTextSharp does not support casting from AcroField back to the orginal class ( RadioCheckField ) that was used to generate the field.

您必须编写自己的代码来解析并检查PDF以实现此目的。

You would have to write your own code to parse and inspect the PDF to achieve this.

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