Itextsharp PDFPTable 如何在整个表格周围制作边框

Question

我正在使用 PDFPTable 通过 Itextsharp 中的数据库构建表格，要求表格中的行/单元格没有顶部或底部边框，但每个单元格的左侧和右侧都有黑色边框（换句话说，每一列都有一个左右边框），表格的底部也需要用黑色边框封闭，这就是我的问题所在。

我正在做的是将边框设置为 0，然后手动分配边框，以便我只获得每个单元格的左右边框，如下所示，作为生成“数量”列的示例：

    cell = new PdfPCell(new Phrase(Qty.value, subheaderFont));
    cell.HorizontalAlignment = Element.ALIGN_CENTER;
    cell.VerticalAlignment = Element.ALIGN_MIDDLE; 
    cell.BackgroundColor = new iTextSharp.text.BaseColor(220, 220, 220);
    cell.Border = 0;
    cell.BorderColorLeft = BaseColor.BLACK;
    cell.BorderWidthLeft = .5f;
    cell.BorderColorRight = BaseColor.BLACK;
    cell.BorderWidthRight = .5f;
    table.AddCell(cell); 

问题显然是我无法检测到最后一行添加边框底部，但我想必须有一种方法来控制“表格”本身的边框，或者我采取了错误的方法到这个？

Answer 1

正如您所发现的，PdfPTable 没有边框，可能是因为 PDF 首先没有表格。将边框直接放在PdfPCell 上可能更有意义（即使PDF 也不支持这些）。无论如何，表格只是单元格的集合，所以让他们处理吧。

无论如何，解决方案是在PdfPTable 类的实例上设置TableEvent。为此，您需要自定义实现 IPdfPTableEvent 接口。以下代码通常应该为您执行此操作（请参阅底部的“一般”注释）

class TopBottomTableBorderMaker : IPdfPTableEvent {
    private BaseColor _borderColor;
    private float _borderWidth;

    /// <summary>
    /// Add a top and bottom border to the table.
    /// </summary>
    /// <param name="borderColor">The color of the border.</param>
    /// <param name="borderWidth">The width of the border</param>
    public TopBottomTableBorderMaker(BaseColor borderColor, float borderWidth ) {
        this._borderColor = borderColor;
        this._borderWidth = borderWidth;
    }
    public void TableLayout(PdfPTable table, float[][] widths, float[] heights, int headerRows, int rowStart, PdfContentByte[] canvases) {
        //widths (should be thought of as x's) is an array of arrays, first index is for each row, second index is for each column
        //The below uses first and last to calculate where each X should start and end
        var firstRowWidths = widths[0];
        var lastRowWidths = widths[widths.Length - 1];

        var firstRowXStart = firstRowWidths[0];
        var firstRowXEnd = firstRowWidths[firstRowWidths.Length - 1] - firstRowXStart;

        var lastRowXStart = lastRowWidths[0];
        var lastRowXEnd = lastRowWidths[lastRowWidths.Length - 1] - lastRowXStart;

        //heights (should be thought of as y's) is the y for each row's top plus one extra for the last row's bottom
        //The below uses first and last to calculate where each Y should start and end
        var firstRowYStart = heights[0];
        var firstRowYEnd = heights[1] - firstRowYStart;

        var lastRowYStart = heights[heights.Length - 1];
        var lastRowYEnd = heights[heights.Length - 2] - lastRowYStart;

        //Where we're going to draw our lines
        PdfContentByte canvas = canvases[PdfPTable.LINECANVAS];

        //I always try to save the previous state before changinge anything
        canvas.SaveState();

        //Set our line properties
        canvas.SetLineWidth(this._borderWidth);
        canvas.SetColorStroke(this._borderColor);

        //Draw some rectangles
        canvas.Rectangle(
                        firstRowXStart,
                        firstRowYStart,
                        firstRowXEnd,
                        firstRowYEnd
                        );
        //They aren't actually drawn until you stroke them!
        canvas.Stroke();

        canvas.Rectangle(
                        lastRowXStart,
                        lastRowYStart,
                        lastRowXEnd,
                        lastRowYEnd
                        );
        canvas.Stroke();

        //Restore any previous settings
        canvas.RestoreState();

    }
}

使用起来很简单，只要给属性绑定一个实例即可：

//Create your name as you normally do
var table = new PdfPTable(3);

//Bind and instance with properties set
table.TableEvent = new TopBottomTableBorderMaker(BaseColor.BLACK, 0.5f);

//The rest is the same
for (var i = 0; i < 6; i++) {
    var cell = new PdfPCell(new Phrase(i.ToString()));
    cell.HorizontalAlignment = Element.ALIGN_CENTER;
    cell.VerticalAlignment = Element.ALIGN_MIDDLE;
    cell.BackgroundColor = new iTextSharp.text.BaseColor(220, 220, 220);
    cell.Border = 0;
    cell.BorderColorLeft = BaseColor.BLACK;
    cell.BorderWidthLeft = .5f;
    cell.BorderColorRight = BaseColor.BLACK;
    cell.BorderWidthRight = .5f;
    table.AddCell(cell);
}

上面我说“通常”它应该可以工作。但是，如果您有表格页眉和/或页脚，您也需要将这些考虑在内。这应该不会太难，但您需要调整 y 的值以考虑 table.HeaderRows 和 table.FooterRows。

Answer 2

我遇到了同样的问题，找到了以下解决方案。 来自“iText In Action 第二版” PdfPCell 扩展了 Rectangle，继承了大量的方法来改变绘制边框和绘制背景的方式..

“DisableBorderSide(int Rectangle)”方法是如何去除涉及任何其他尺寸的边框。

PdfPCell cell = new PdfPCell(new Phrase("Some Text", FontFactory.GetFont("Arial", BaseFont.WINANSI, BaseFont.EMBEDDED, 13, Font.NORMAL, BaseColor.BLACK)));
cell.BackgroundColor = new BaseColor(255, 255, 255);
cell.HorizontalAlignment = Element.ALIGN_CENTER;
cell.BorderColor = BaseColor.BLACK;
cell.Border = Rectangle.BOX;
cell.BorderWidth = 1;
cell.DisableBorderSide(Rectangle.TOP_BORDER);
cell.DisableBorderSide(Rectangle.BOTTOM_BORDER);
cell.Padding = 3;
table.AddCell(cell);

Answer 3

我使用嵌套表解决了这个问题

'CREATE TWO PDFPTABLES
 Dim tblNested1 As New PdfPTable(1)
 Dim tblNested2 As New PdfPTable(3)

 'CREATE CELLS WITH NO BORDER AND ADD THEM TO TABLE2

 Dim cellNested1 = New PdfPCell(New Phrase("CELL1"))
 cellNested1.Border = 0
 tblNested2.AddCell(cellNested1)
 Dim cellNested2 = New PdfPCell(New Phrase("CELL2"))
 cellNested2.Border = 0
 tblNested2.AddCell(cellNested2)
 Dim cellNested3 = New PdfPCell(New Phrase("CELL3"))
 cellNested3.Border = 0
 tblNested2.AddCell(cellNested3)

 'APPEND TABLE2 TO A CELL WITH DEFAULT BORDER

  Dim cell1 As New PdfPCell
  cell1.AddElement(tblNested2)

  tblNested1.AddCell(cell1)

  document.Add(tblNested1)

Answer 4

 var Rectangular = new Rectangle(56, 621, 540,385);
                Rectangular.BorderWidthLeft = 0.1f;
                Rectangular.BorderWidthRight = 0.1f;
                Rectangular.BorderWidthTop = 0.1f;
                Rectangular.BorderWidthBottom = 0.1f;
                cb.Rectangle(Rectangular);
                cb.Stroke();