How to put a table in the center of the page?

Question

With MigraDoc I'm trying to put a table in the center of the page. I'm using this code (c#, VS).

Section secondPage = new Section(); 
Table table = new Table();
AddColumns(table);
AddFirstRow(table);
AddSecondRow(table);
table.Format.Alignment=ParagraphAlignment.Center;
secondPage.Add(table);

I get a table aligned to the right of the page; how can I obtain a table in the center of the page?

George

Answer 1

You can set table.Rows.LeftIndent to indent the table. To get a centered table, calculate the indent based on paper size, page margins, and table width.

Example: Paper size is A4 (21 cm wide), left and right margins are 2.5 cm each. Thus we have a page body of 16 cm.
To center a table that is 12 cm wide, table.Rows.LeftIndent must be set to 2 cm (16 cm body width minus 12 cm table width gives 4 cm remaining space - half of the remaining space must be set as the LeftIndent).
From the code snippet in the original question, remove table.Format.Alignment=ParagraphAlignment.Center; and replace it with table.Rows.LeftIndent="2cm";.

Note that this will also work if the table is slightly wider than the body, but still within page edges. Using the page setup from the previous example, a table that is 18 cm wide can be centered with a LeftIndent of -1 cm.

Sample code (the table has just a single column):

var doc = new Document();
var sec = doc.AddSection();

// Magic: To read the default values for LeftMargin, RightMargin &c. 
// assign a clone of DefaultPageSetup.
// Do not assign DefaultPageSetup directly, never modify DefaultPageSetup.
sec.PageSetup = doc.DefaultPageSetup.Clone();

var table = sec.AddTable();
// For simplicity, a single column is used here. Column width == table width.
var tableWidth = Unit.FromCentimeter(8);
table.AddColumn(tableWidth);
var leftIndentToCenterTable = (sec.PageSetup.PageWidth.Centimeter - 
                               sec.PageSetup.LeftMargin.Centimeter - 
                               sec.PageSetup.RightMargin.Centimeter -
                               tableWidth.Centimeter) / 2;
table.Rows.LeftIndent = Unit.FromCentimeter(leftIndentToCenterTable);
table.Borders.Width = 0.5;
var row = table.AddRow();
row.Cells[0].AddParagraph("Hello, World!");

The sample code uses Centimeter for calculations. You can also use Inches, Millimeter, Picas or Points. Default page size is A4 and in the sample the LeftIndent will be 4 cm.

Reclamation

give an example of the calculation, not just a description – Hermitage

@PDFsharpExpert how does one get those numbers (Paper size=21cm, left and right margins=2.5cm each) using the API? I accept the basic math of (21-(2.5x2)-12)/2 = 4/2 = 2, but I would like to see the code for obtaining 21 and 2.5 from the API. Thanks. – Hermitage

@Hermitage With MigraDoc you can only query those values after you set them. If your code does not set them, then you know the default values will be used (width 21 cm, left and right margins 2.5 cm). If your code sets them then you can query them - but your code already knows them without querying them because your code set them. I blew up the answer by adding code to that effect. The benefit is that you can query the default values when using the trick from the sample code. – Reclamation

@PDFsharpExpert epic. Thanks for modifying your answer. The bit about cloning the DefaultPageSetup is a fantastic addition. Most people don't read the docs thoroughly, so this will help people see it. – Hermitage

Answer 2

To center a table in the center of a section.

table.Rows.Alignment = RowAlignment.Center;

Titer

Works perfectly with no calcultion at all. – Fredric

perfect than the question was accepted! 👍 – Adaminah