I believe your first problem is that the scope of the solution is too broad. You're not likely to find a single "print all the things" library, since printing something requires a rendering engine in and of itself. If you're dealing with specific types of files that you want to print, you should be able to categorize them into groups: PDF, Image, Text, etc.
You will then have to provide a rendering engine (either .NET, a downloaded library, or something custom) for each category.
You could use the built-in .NET Drawing namespace types to handle image printing pretty easily. Using the PrintDocument class isn't much different that using the System.Drawing.Graphics class, and would only require code to make sure that the printed image was scaled to fit the printing bounds.
Same with printing straight text. Using the System.Drawing.StringFormat class to define how the text is rendered, and define the bounds as the printable area of the page and then it's just a call to DrawText(). Below is some code from an old project to print text from a RichTextBox WinForms control, while doing some custom alteration to add line numbers to the printed output.
public void Print()
{
this.InitPrintDocument();
using (System.Windows.Forms.PrintDialog dlg = new System.Windows.Forms.PrintDialog())
{
dlg.AllowSomePages = false;
dlg.AllowSelection = false;
dlg.AllowPrintToFile = false;
dlg.AllowCurrentPage = false;
if (dlg.ShowDialog(this) == System.Windows.Forms.DialogResult.OK)
{
this._printDoc.PrinterSettings = dlg.PrinterSettings;
this._printDoc.Print();
}
}
}
private void InitPrintDocument()
{
if (this._printDoc != null)
this._printDoc.Dispose();
this._printDoc = new System.Drawing.Printing.PrintDocument();
this._printDoc.BeginPrint += new System.Drawing.Printing.PrintEventHandler(this.printDocument_onBeginPrint);
this._printDoc.PrintPage += new System.Drawing.Printing.PrintPageEventHandler(this.printDocument_onPrintPage);
}
private void printDocument_onBeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
{
this._lastPrintLine = 0;
}
private void printDocument_onPrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
string pgTxt = "";
this.SuspendRefresh();
this.SuspendScroll();
int stChar = this.GetFirstCharIndexFromLine(this._lastPrintLine),
stLn = this._lastPrintLine,
selStart = this.SelectionStart,
selLength = this.SelectionLength;
try
{
using (StringFormat fmt = new StringFormat(StringFormatFlags.LineLimit))
{
int lnCnt = this.Lines.Length;
SizeF lnNumSz = e.Graphics.MeasureString("0000", this.Font);
float numMarginWidth = lnNumSz.Width + 2.0f;
while (e.Graphics.MeasureString(pgTxt, this.Font, new Size(e.MarginBounds.Size.Width - (int)numMarginWidth, e.MarginBounds.Size.Height), fmt).Height < e.MarginBounds.Height - (e.MarginBounds.Top / 2) && this._lastPrintLine < this.Lines.Length)
pgTxt += ((pgTxt.Length > 0) ? "\n" : "") + this.Lines[this._lastPrintLine++];
bool newLine = true;
PointF nextCharPos = new PointF((float)e.MarginBounds.Left + numMarginWidth, (float)e.MarginBounds.Top);
RectangleF numMarginBounds = new RectangleF((float)e.MarginBounds.Left, (float)e.MarginBounds.Top, numMarginWidth, (float)e.MarginBounds.Height);
using (SolidBrush numBrush = new SolidBrush(Color.FromArgb(200, 200, 200)))
e.Graphics.FillRectangle(numBrush, numMarginBounds);
for (int i = 0; i < pgTxt.Length; i++)
{
this.SelectionStart = stChar + i;
if (newLine)
{
RectangleF numRect = new RectangleF(e.MarginBounds.Left, nextCharPos.Y, numMarginWidth, lnNumSz.Height);
using (StringFormat format = new StringFormat(StringFormatFlags.NoWrap))
{
format.Alignment = StringAlignment.Far;
e.Graphics.DrawString(Convert.ToString(this.GetLineFromCharIndex(stChar + i) + 1), this.Font, Brushes.DarkGreen, numRect, format);
}
}
string nextChar = pgTxt.Substring(i, 1);
if (nextChar != "\n")
{
SelectionLength = 1;
Color curCol = this.SelectionColor;
SizeF charSz = e.Graphics.MeasureString(nextChar, this.Font);
if (nextCharPos.X + (charSz.Width / 1.5) > (e.MarginBounds.Width / 0.9))
nextCharPos = new PointF((float)e.MarginBounds.Left + numMarginWidth, nextCharPos.Y + (charSz.Height / 1.105f));
using (SolidBrush brush = new SolidBrush(curCol))
e.Graphics.DrawString(nextChar, this.Font, brush, nextCharPos);
nextCharPos = new PointF(nextCharPos.X + charSz.Width / ((nextChar != " ") ? 1.5f : 0.9f), nextCharPos.Y);
newLine = false;
}
else
{
newLine = true;
SizeF charSz = e.Graphics.MeasureString("W", this.Font);
nextCharPos = new PointF((float)e.MarginBounds.Left + numMarginWidth, nextCharPos.Y + (charSz.Height / 1.105f));
}
}
e.HasMorePages = (this._lastPrintLine < this.Lines.Length);
if (!e.HasMorePages)
{
e.Graphics.FillRectangle(Brushes.White, new RectangleF(0.0f, nextCharPos.Y + lnNumSz.Height, e.PageBounds.Width, e.MarginBounds.Bottom - (nextCharPos.Y + lnNumSz.Height)));
}
}
}
catch (Exception ex)
{
System.Windows.Forms.MessageBox.Show(this, "Unable to generate page for printing:\n\n" + ex.Message, "Unexpected Error");
}
finally
{
this.SelectionStart = selStart;
this.SelectionLength = selLength;
this.ResumeScroll();
this.ResumeRefresh();
}
}
PDF's are more difficult to render, but there are plenty of pre-built libraries out there to handle that. ITextSharp, of course, is one of the most powerful and flexible, but also tends to be complicated to use. If all you're looking to do is print, I recommend checking out PDFSharp, since the library follows the typical .NET method naming guidelines and is more intuitive to code against.
http://pdfsharp.com/PDFsharp/
