Question

我找到了一个很好的示例，展示了如何在此处为新复选框设置复选框导出值（以及其他属性）（请参见“ CreateCheckBoxList”示例）：

https://simpledotnetsolutions.wordpress.com/2012/11/01/itextsharp-creating-form-fields/

但是，我需要更改现有复选框的导出值。我尝试以几种不同的方式修改上述示例，但没有任何效果。

请澄清一下，下图显示了我希望使用iText以编程方式更改的checkbox属性：

Answer 1

PdfReader reader = new PdfReader(@"C:\test.pdf");
AcroFields fields = reader.AcroFields;

int i = 0;
string checkboxExportValues = "Count\tName\tExport Value\r\n";

//loop all fields in the pdf    
foreach (KeyValuePair<string, AcroFields.Item> kpv in fields.Fields)
{
    string exportValue = "";
    switch (fields.GetFieldType(kpv.Key))
    {
        //if the field is a checkbox, get the field's name and export value
        case AcroFields.FIELD_TYPE_CHECKBOX:
            AcroFields checkbox = reader.AcroFields;
            String[] values = checkbox.GetAppearanceStates(kpv.Key);

            //get the last checkbox state, which represents a selected checkbox
            foreach (String value in values)
            {
                exportValue = value;
            }
            checkboxExportValues = checkboxExportValues + i + "\t" + kpv.Key + "\t" + exportValue + "\r\n";
        break;
   }
   i++;
}
reader.Close();
File.WriteAllText(@"C:\exportValues.txt", checkboxExportValues);

/*
Sample output:
Count    Name    Export Value
1    Check Box106    Yes
2    Check Box107    Yes
3    Check Box122    1
4    Check Box127    On
5    Check Box128    2
*/

Answer 2

我也有相同的要求，并找到了您的帖子。由于我没有找到任何相关的内容，因此我自己实施了它。不幸的是，它是Java语言，但您可以将其转换为C＃。请注意：

为了方便查看，我缩短了代码-您必须添加自己的错误处理等。
我假设一个复选框有两个外观：（1）代表未选中状态（/ Off），一个代表选中状态（2），可以自由选择
您可能还必须更改/ Opt数组（如果存在）

下面是代码：

[...]

case (AcroFields.FIELD_TYPE_CHECKBOX):

 PdfDictionary ap = item.getWidget(i).getAsDict(PdfName.AP);
 if (ap != null) {
    PdfDictionary normalAp = ap.getAsDict(PdfName.N);
    changeAppearanceStateNames(normalAp, "NewExportValue", "Check Box106");

    PdfDictionary downAp = ap.getAsDict(PdfName.D);
    changeAppearanceStateNames(downAp, "NewExportValue", "Check Box106"););

    PdfDictionary rolloverAp = ap.getAsDict(PdfName.R);
    changeAppearanceStateNames(rolloverAp, "NewExportValue", "Check Box106");
 }
break; [...]

private void changeAppearanceStateNames(PdfDictionary appearanceSubdictionary, String newValue, String fieldname) throws NotSpecCompliantException {
    if (appearanceSubdictionary != null) {
        if(appearanceSubdictionary.size()>2) throw Exception ...

        String appearanceSubDictionaryName=null;

        //detect name for the checked value
        for(Object key : appearanceSubdictionary.getKeys()) {
            String name = PdfName.decodeName(((PdfName)key).toString());

            if(!name.equals("Off")) {
                appearanceSubDictionaryName=name;
            }
        }

        //update it
        if(appearanceSubDictionaryName!=null) {
            PdfObject appearanceSubDictionaryValue = appearanceSubdictionary.get(new PdfName(appearanceSubDictionaryName));
            appearanceSubdictionary.remove(new PdfName(appearanceSubDictionaryName));
            appearanceSubdictionary.put(new PdfName(newValue),appearanceSubDictionaryValue);
        }
        //else {
            //theoretically create a new appearance here. Details can be seen in the #RadioCheckField
            //however since only the export value should be changed it is assumed that the actual appearance dictionary does already exists
        //}
    }
}

如何使用iText

2 个答案: