Class for generating PDF documents

Question

Following is a chunk of code from my class which generates PDF documents. I am refactoring my code and in the process I have created short methods. But I have to pass 'table i.e PdfPTable' to my methods again and again. How can I avoid this?

PdfPTable orgTable = new PdfPTable(2);
PdfPCell cell = null;
string orgName = dr["OrganizationName"].ToString();
cell = new PdfPCell(new Phrase(orgName, Heading1)) {Colspan = 2, BackgroundColor = BckColor, HorizontalAlignment = Element.ALIGN_CENTER };
orgTable.AddCell(cell);

AddOrganizationProfile(document, dr, orgTable);
OrganizationHeadOffice(document, dr, orgTable);
OrganizationContacts(document, orgTable, orgId);

private void OrganizationHeadOffice(Document document, DataRow dr, PdfPTable table)
{
    AddTitle("Office Contact & Information:", table);

    // How to avoid passing table variable again and again here.
    AddLegend("Address:", table);
    AddDataValue(dr["address"].ToString(), table);
    AddLegend("Contact Number:", table);
    AddDataValue(phone1, table);
}

private void AddTitle(string title, PdfPTable table)
{
    table.AddCell(new PdfPCell(new Phrase(title, TableFontCaption)) { Colspan = 2, BackgroundColor = BckColor });
}

private void AddLegend(string legend, PdfPTable table)
{
    table.AddCell(new PdfPCell() { Border = Rectangle.NO_BORDER, Phrase = new Phrase(legend, TableFontCaption) });
}

private void AddDataValue(string dataValue, PdfPTable table)
{
    table.AddCell(new PdfPCell() { Border = Rectangle.NO_BORDER, Phrase = new Phrase(dataValue, TableFont) });
}

Answer 1

Make PdfPTable a property of the class and set it in the constructor.

Answer 2

This looks like a good candidate for the Builder pattern.

You have a PdfPTableBuilder class, whose sole responsibility is to (of course) build a PdfPTable instance. You initialize it and call various setter methods, and each method returns this, so that you can chain them:

PdfPTableBuilder builder = new PdfPTableBuilder();
builder.AddLegend("Address:").AddDataValue(dr["address"].ToString());
// etc.
return builder.build();

The builder itself simply holds all the data it needs to construct the table instance, and pours that into the table in the build method.

Answer 3

Another option which has not yet been covered would be extension methods.

If the code inside your methods is not specific to the class that is calling it, by which I mean if the AddTitle method would be exactly the same regardless of which class wanted to create a PDF, you could make it an extension method by moving it to a static class

public static class PdfPTableExtensions
{
    public static void AddTitle(this PdfPTable table, string title)
    {
        table.AddCell(new PdfPCell(new Phrase(title, TableFontCaption)) { Colspan = 2, BackgroundColor = BckColor });
    }
}

which you can then call as follows:

table.AddTitle("Office Contact & Information:");

Answer 4

Your methods, as they stand, appear to be able to be static. In other words, there is no reliance on class state at all. Make orgTable a member of the class and have each method access it as this.orgTable rather than as a method parameter.

Answer 5

Expanding on the answer from @CarlManaster:

You can have your "builder" extend IEnumerable, then add an Add(PdfTableItemType cellType, string content) method, and then add items using the collection initializer.

Sample usage

public static PdfPTable ReticulateSplines() {
    PdfPTableBuilder builder = new PdfPTableBuilder() {
        { PdfTableItemType.Title, "Office Contact & Information:" },
        { PdfTableItemType.Legend, "Address:" },
        // ...
    };
    // Or, if you prefer:
    builder.Add(PdfTableItemType.DataValue, "address".ToString());
    // etc.
    //return builder.Build();
}

Example skeleton for the builder

public class PdfPTableBuilder : IEnumerable
{
    public enum PdfTableItemType
    {
        Title,
        Legend,
        DataValue,
    }

    public IEnumerator GetEnumerator() {
        throw new NotImplementedException();
    }

    public void Add(PdfTableItemType cellType, string content) {
        switch (cellType) {
            case PdfTableItemType.Title:
                // table.AddCell(...);
                break;
            // etc;
        }
    }

    public PdfTable Build() {
        throw new NotImplementedException();
    }
    public class PdfTable { } // Dummy.
}