An exception of type 'System.OutOfMemoryException' occurred in itextsharp.dll but was not handled in user code

Question

I am using iTextSharp to create pdf. I have 100k records, but I am getting following exception:

An exception of type 'System.OutOfMemoryException' occurred in itextsharp.dll but was not handled in user code At the line: bodyTable.AddCell(currentProperty.GetValue(lst, null).ToString());

Code is:

var doc = new Document(pageSize);

PdfWriter.GetInstance(doc, stream);
doc.Open();

//Get exportable count
int columns = 0;

Type currentType = list[0].GetType();

//PREPARE HEADER
//foreach visible columns check if current object has proerpty
//else search in inner properties
foreach (var visibleColumn in visibleColumns)
{
    if (currentType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key) != null)
    {
        columns++;
    }
    else
    {
        //check child property objects
        var childProperties = currentType.GetProperties();
        foreach (var prop in childProperties)
        {
            if (prop.PropertyType.BaseType == typeof(BaseEntity))
            {
                if (prop.PropertyType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key) != null)
                {
                    columns++;
                    break;
                }
            }
        }
    }
}


//header
var headerTable = new PdfPTable(columns);
headerTable.WidthPercentage = 100f;

foreach (var visibleColumn in visibleColumns)
{
    if (currentType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key) != null)
    {
        //headerTable.AddCell(prop.Name);
        headerTable.AddCell(visibleColumn.Value);
    }
    else
    {
        //check child property objects
        var childProperties = currentType.GetProperties();
        foreach (var prop in childProperties)
        {
            if (prop.PropertyType.BaseType == typeof(BaseEntity))
            {
                if (prop.PropertyType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key) != null)
                {
                    //headerTable.AddCell(prop.Name);
                    headerTable.AddCell(visibleColumn.Value);
                    break;
                }
            }
        }
    }
}

doc.Add(headerTable);

var bodyTable = new PdfPTable(columns);
bodyTable.Complete = false;
bodyTable.WidthPercentage = 100f;

//PREPARE DATA
foreach (var lst in list)
{
    int col = 1;
    foreach (var visibleColumn in visibleColumns)
    {
        var currentProperty = currentType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key);
        if (currentProperty != null)
        {
            if (currentProperty.GetValue(lst, null) != null)
                bodyTable.AddCell(currentProperty.GetValue(lst, null).ToString());
            else
                bodyTable.AddCell(string.Empty);

            col++;
        }
        else
        {
            //check child property objects
            var childProperties = currentType.GetProperties().Where(p => p.PropertyType.BaseType == typeof(BaseEntity));
            foreach (var prop in childProperties)
            {
                currentProperty = prop.PropertyType.GetProperties().FirstOrDefault(p => p.Name == visibleColumn.Key);
                if (currentProperty != null)
                {
                    var currentPropertyObjectValue = prop.GetValue(lst, null);
                    if (currentPropertyObjectValue != null)
                    {
                        bodyTable.AddCell(currentProperty.GetValue(currentPropertyObjectValue, null).ToString());
                    }
                    else
                    {
                        bodyTable.AddCell(string.Empty);
                    }
                    break;
                }
            }
        }
    }
}

doc.Add(bodyTable);

doc.Close();

Answer 1

A back of the envelope computation of the memory requirements given the data you provided for memory consumption gives 100000 * 40 * (2*20+4) = 167MBs. Well within your memory limit, but it is just a lower bound. I imagine each Cell object is pretty big. If each cell would have a 512 byte overhead you could be well looking at 2GB taken. I reckon it might be even more, as PDF is a complex beast.

So you might realistically be looking at a situation where you are actually running out of memory. If not your computers, then at least the bit C# has set aside for its own thing.

I would do one thing first - check memory consumption like here . You might even do well to try with 10, 100, 1000, 10000, 100000 rows and see up until what number of rows the program works.

You could perhaps try a different thing altogether. If you're trying to print a nicely formatted table with a lot of data, perhaps you could output an HTML document, which can be done incrementally and which you can do by just writing stuff to a file, rather than using a third party library. You can then "print" that HTML document to PDF. StackOverflow to the rescue again with this problem.