How do I know when to add a new page? - itext

Question

So I'm generating tables with cells based on some data that I get from a database.
And my question is simple, how do I know when to create a new page? I would have to calculate the height of each table and make sure that they're within the size of the page, and if the next table isn't, well then create a new page and add it to that one.
The issue is I'm not sure if this is the right approach. Is this how you would do it? And if so, how do I calculate the height of a table because myTable.GetHeight().GetValue(); throws a nullreference exception because GetHeight() returns null.

Answer 1

First of all table.GetHeight().GetValue() returns null because you are %99 not setting your table's height.
For Example :
var table1 = new Table(1);
var height1 = table1.GetHeight().GetValue(); // This throws exception because we are not setting the height in here.
var table2 = new Table(1).SetHeight(20);
var height2 = table2.GetHeight().GetValue(); // This line returns 20, because you have set the value of height
For your main issue,
You can take the default page size with the below code, and set your table's height
var defaultPageHeight = pdfDocument.GetDefaultPageSize().GetHeight();
var table = new Table(1).UseAllAvailableWidth().SetHeight(defaultPageHeight);
But this wouldnt be a good approach, I think a good approach would be using a TableRenderer
Little Example:
public class CustomTableRenderer : TableRenderer
{
protected Document document;
public class CustomTableRenderer(Table modelElement, Document document) : base(modelElement)
{
this.document = document;
}
public override IRenderer GetNextRenderer()
{
// Add a header everytime a new page is created with this renderer
var header = new Table(1).UseAllAvailableWidth();
header.AddCell(new Cell().Add(new Paragraph("Title")));
document.Add(header);
return new CustomTableRenderer((Table)GetModelElement())
}
public override void Draw(DrawContext drawContext)
{
// This is the part where you create your layout for every time this renderer calls.
var defaultPageHeight = drawContext.GetDocument().GetDefaultPageSize().GetHeight();
// And you can do other things
}
}