使用 iTextSharp 将表单元素添加到表格中
本文关键字：表格 添加 元素 iTextSharp 表单 使用 | 更新日期: 2023-09-27 18:35:34
我正在尝试创建一个PDF文档，该文档本质上是表格格式的用户列表。我需要表格中包含复选框。到目前为止，我分别拥有表格和复选框，但我找不到在表格中获取复选框的方法。我想我需要使用 AddCell（） 方法添加它们。
这是我的代码：
static void Main(string[] args)
{
// create the document, filestream, writer
Document doc = new Document(PageSize.LETTER);
FileStream file = new FileStream(@"C:'Users'test'User List.pdf", FileMode.OpenOrCreate);
PdfWriter writer = PdfWriter.GetInstance(doc, file);
try
{
// metadata
doc.AddAuthor("Test User");
doc.AddCreator("Test Document");
doc.AddKeywords("Test Document");
doc.AddSubject("Test Document");
doc.AddTitle("Test Document - Test User");
// open up the PDF document
doc.Open();
PdfContentByte cb = writer.DirectContent;
Font _bf = new Font(Font.FontFamily.HELVETICA, 9);
// create a table
PdfPTable table = new PdfPTable(3);
PdfPCell cell = new PdfPCell(new Phrase("User List"));
PdfFormField field = PdfFormField.CreateCheckBox(writer);
field.SetWidget(new Rectangle(40, 500, 60, 530), PdfAnnotation.HIGHLIGHT_INVERT);
field.SetFieldFlags(PdfAnnotation.FLAGS_PRINT);
field.FieldName = "Delete";
writer.AddAnnotation(field);
cell.Colspan = 3;
cell.HorizontalAlignment = 0; //0 = left, 1 = center, 2 = right
cell.VerticalAlignment = 1;
table.AddCell("No.");
table.AddCell("Users");
table.AddCell("Delete");
// create form fields
PdfAppearance[] onOff = new PdfAppearance[2];
Rectangle rect;
PdfFormField checkbox;
RadioCheckField _checkbox;
onOff[0] = cb.CreateAppearance(10, 10);
onOff[0].Rectangle(1, 1, 8, 8);
onOff[0].Stroke();
onOff[1] = cb.CreateAppearance(10, 10);
onOff[1].SetRGBColorFill(255, 128, 128);
onOff[1].Rectangle(1, 1, 8, 8);
onOff[1].FillStroke();
onOff[1].MoveTo(1, 1);
onOff[1].LineTo(9, 9);
onOff[1].MoveTo(1, 9);
onOff[1].LineTo(9, 1);
onOff[1].Stroke();
for (int i = 0; i < 5; i++)
{
table.AddCell(i.ToString());
table.AddCell("User " + i);
//rect = new Rectangle(400, 675 - i*40, 415, 663 - i*40);
rect = new Rectangle(400, 735 - i * 40, 415, 723 - i * 40);
_checkbox = new RadioCheckField(writer, rect, "User "+(i+1), "Yes");
checkbox = _checkbox.CheckField;
checkbox.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, "Off", onOff[0]);
checkbox.SetAppearance(PdfAnnotation.APPEARANCE_NORMAL, "On", onOff[1]);
writer.AddAnnotation(checkbox);
// this is where I am trying to add the checkbox to the table
// what can I add to AddCell() to make the checkbox show up?
table.AddCell();
//ColumnText.ShowTextAligned(cb, Element.ALIGN_LEFT, new Phrase("User " + (i + 1), _bf), 50, 665 - i * 40, 0);
}
cb = writer.DirectContent;
doc.Add(table);
}
catch(DocumentException dex)
{
throw (dex);
}
finally
{
// close
doc.Close();
writer.Close();
file.Close();
}
}
有没有办法使用iTextSharp来做到这一点？也许有更好的库可以使用？
我将参考iText网站，展示如何将字段传递给自定义IPdfPCellEvent实现，以及如何创建该自定义类并在下面的C#中重新创建它。
首先，创建一个实现IPdfPCellEvent的类：
public class ChildFieldEvent : IPdfPCellEvent {
/** A parent field to which a child field has to be added. */
protected PdfFormField parent;
/** The child field that has to be added */
protected PdfFormField kid;
/** The padding of the field inside the cell */
protected float padding;
/**
* Creates a ChildFieldEvent.
* @param parent the parent field
* @param kid the child field
* @param padding a padding
*/
public ChildFieldEvent(PdfFormField parent, PdfFormField kid, float padding) {
this.parent = parent;
this.kid = kid;
this.padding = padding;
}
/**
* Add the child field to the parent, and sets the coordinates of the child field.
*/
public void CellLayout(PdfPCell cell, iTextSharp.text.Rectangle rect, PdfContentByte[] cb) {
parent.AddKid(kid);
kid.SetWidget(new iTextSharp.text.Rectangle(
rect.GetLeft(padding),
rect.GetBottom(padding),
rect.GetRight(padding),
rect.GetTop(padding)
),
PdfAnnotation.HIGHLIGHT_INVERT
);
}
}
然后，只需在应该包含字段的任何单元格上设置CellEvent即可。
//File to create
var testFile = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.Desktop), "test.pdf");
//Standard PDF creation, nothing special here
using (var fs = new FileStream(testFile, FileMode.Create, FileAccess.Write, FileShare.None)) {
using (var doc = new Document()) {
using (var writer = PdfWriter.GetInstance(doc, fs)) {
doc.Open();
//Create a root form object that we'll add "children" to. This way we don't have to add each "child" annotation to the writer
var root = PdfFormField.CreateEmpty(writer);
root.FieldName = "root";
//Create a two column table
var t = new PdfPTable(2);
//Add a basic cell
t.AddCell("First Name");
//Create our textfield, the rectangle that we're passing in is ignored and doesn't matter
var tf = new TextField(writer, new iTextSharp.text.Rectangle(0, 0), "first-name");
//Create a new cell
var cell = new PdfPCell();
//Set the cell event to our custom IPdfPCellEvent implementation
cell.CellEvent = new ChildFieldEvent(root, tf.GetTextField(), 1);
//Add the cell to our table
t.AddCell(cell);
//Add the table to the document
doc.Add(t);
//IMPORTANT! Add the root annotation to the writer which also adds all of the child annotations
writer.AddAnnotation(root);
//Clean up
doc.Close();
}
}
}