Question

我正在尝试设置一个简单的2列页面，写入第一列，然后写入第二列。但是，下面的代码将两个段落放在第二列中。当前列跟踪似乎是正确的（先0，然后1）

任何想法我做错了什么？

MultiColumnText columns = new MultiColumnText();

columns.AddSimpleColumn(0, 200);
columns.AddSimpleColumn(200, 400);

Paragraph para1 = new Paragraph("Para1");
columns.AddElement(para1);

Response.Write(columns.CurrentColumn);//traces 0

columns.NextColumn();

Response.Write(columns.CurrentColumn);//traces 1

Paragraph para2 = new Paragraph("Para2");
columns.AddElement(para2);

doc.Add(columns);

非常感谢

奥利弗

Answer 1

我无法让NextColumn()与MultiColumnText对象一起工作，但我找不到任何样本（在.NET中）。

MultiColumnText使得在文档中创建列相对容易，但作为交换，您放弃了对布局的大量控制。您可以使用ColumnText对象，它可以对列布局进行大量控制，但需要更多代码。

以下是使用ColumnText尝试执行的操作的简单但完整的示例：

    private void TestColumnText() {
        using (FileStream fs = new FileStream("ColumnTest.pdf", FileMode.Create)) {
            Document doc = new Document();
            PdfWriter writer = PdfWriter.GetInstance(doc, fs);
            doc.Open();

            PdfContentByte cb = writer.DirectContent;
            ColumnText ct = new ColumnText(cb);

            float columnWidth = 200f;
            float[] left1  = { doc.Left + 90f, doc.Top - 80f, doc.Left + 90f, doc.Top - 170f, doc.Left, doc.Top - 170f, doc.Left, doc.Bottom };
            float[] right1 = { doc.Left + columnWidth, doc.Top - 80f, doc.Left + columnWidth, doc.Bottom };
            float[] left2  = { doc.Right - columnWidth, doc.Top - 80f, doc.Right - columnWidth, doc.Bottom };
            float[] right2 = { doc.Right, doc.Top - 80f, doc.Right, doc.Bottom };

            // Add content for left column.
            ct.SetColumns(left1, right1);
            ct.AddText(new Paragraph("Para 1"));
            ct.Go();

            // Add content for right column.
            ct.SetColumns(left2, right2);
            ct.AddText(new Paragraph("Para 2"));
            ct.Go();

            doc.Close();
        }
    }

警告：正如我所提到的，这是一个简单的示例，甚至不会作为您尝试做的事情的起点。以下网站上的样本（特别是第一个）将帮助您：

http://www.mikesdotnetting.com/Article/89/iTextSharp-Page-Layout-with-Columns http://www.devshed.com/c/a/Java/Adding-Columns-With-iTextSharp

Answer 2

当我发现iTextSharp的最新版本不包括MultiColumnText类时，我创建了我自己的一类。

Public Class SimpleColumnText
    Inherits ColumnText

    Dim workingDocument As Document
    Dim columns As New List(Of Rectangle)
    Dim currentColumn As Integer = 0

    Public Sub New(content As PdfContentByte, columnCount As Integer, columnSpacing As Single, document As Document)
        MyBase.New(content)

        workingDocument = document
        CalculateColumnBoundries(columnCount, columnSpacing)
    End Sub

    Private Sub CalculateColumnBoundries(columnCount As Integer, columnSpacing As Single)
        Dim columnWidth As Single
        Dim columnHeight As Single

        With workingDocument
            columnWidth = ((.PageSize.Width - .LeftMargin - .RightMargin) - (columnSpacing * (columnCount - 1))) / columnCount
            columnHeight = (.PageSize.Height - .TopMargin - .BottomMargin)
        End With

        For x = 0 To columnCount - 1
            Dim llx As Single = ((columnWidth + columnSpacing) * x) + workingDocument.LeftMargin
            Dim lly As Single = workingDocument.BottomMargin
            Dim urx As Single = llx + columnWidth
            Dim ury As Single = columnHeight

            Dim newRectangle As New Rectangle(llx, lly, urx, ury)

            columns.Add(newRectangle)

        Next
    End Sub

    Public Shadows Sub AddElement(element As IElement)
        MyBase.AddElement(element)

        'we have to see if there is a column on the page before we begin
        Dim status As Integer

        If currentColumn = 0 Then
            status = ColumnText.NO_MORE_COLUMN
        End If

        Do
            If status = ColumnText.NO_MORE_COLUMN Then
                If currentColumn = columns.Count Then
                    'we need a new page
                    workingDocument.NewPage()
                    'reset column count
                    currentColumn = 0
                End If
                MyBase.SetSimpleColumn(columns(currentColumn))
                currentColumn += 1
            End If

            status = MyBase.Go()
        Loop While ColumnText.HasMoreText(status)
    End Sub
End Class

这可以很容易地扩展到Shadow中的其他功能ColumnText。

Answer 3

谢谢cjbarth，这很有用。我在C＃中做了类似的版本，如果这有助于任何人。

public class ColumnTextSimple : ColumnText
{
    Document document;
    Rectangle[] columns;

    public ColumnTextSimple(PdfContentByte writer, Document workingDocument, int columnCount, float columnSpacing) : base(writer)
    {
        document = workingDocument;
        CalculateColumns(columnCount, columnSpacing);
    }

    private void CalculateColumns(int columnCount, float columnSpacing)
    {
        float columnWidth;
        float columnHeight;

        columnWidth = ((document.PageSize.Width - document.LeftMargin - document.RightMargin) - (columnSpacing * (columnCount - 1))) / columnCount;
        columnHeight = (document.PageSize.Height - document.TopMargin - document.BottomMargin);

        columns = new Rectangle[columnCount];

        for (int c = 0; c < columnCount; c++)
        {
            float llx  = ((columnWidth + columnSpacing) * c) + document.LeftMargin;
            float lly  = document.BottomMargin;
            float urx  = llx + columnWidth;
            float ury  = columnHeight;

            columns[c] = new Rectangle(llx, lly, urx, ury);
        }
    }

    public void produceColumns()
    {
        int column = 0;
        int status = 0;

        while (ColumnText.HasMoreText(status))  // same as while(status != 1)
        {
            if (column >= columns.Length)
            {
                column = 0;
                document.NewPage();
            }
            this.SetSimpleColumn(columns[column]);
            status = this.Go();
            column++;
        }
    }
}

我为ProduceColumns添加了一个单独的方法，因为这允许多次调用AddElement。一旦添加了所有内容，就必须调用ProduceColumns。

itextsharp nextcolumn不工作

3 个答案: