I want to print HTML from a C# web service. The web browser control is overkill, and does not function well in a service environment, nor does it function well on a system with very tight security constraints. Is there any sort of free .NET
library that will support the printing of a basic HTML page? Here is the code I have so far, which does not run properly.
public void PrintThing(string document)
{
if (Thread.CurrentThread.GetApartmentState() != ApartmentState.STA)
{
Thread thread =
new Thread((ThreadStart) delegate { PrintDocument(document); });
thread.SetApartmentState(ApartmentState.STA);
thread.Start();
}
else
{
PrintDocument(document);
}
}
protected void PrintDocument(string document)
{
WebBrowser browser = new WebBrowser();
browser.DocumentText = document;
while (browser.ReadyState != WebBrowserReadyState.Complete)
{
Application.DoEvents();
}
browser.Print();
}
This works fine when called from UI-type threads, but nothing happens when called from a service-type thread. Changing Print()
to ShowPrintPreviewDialog()
yields the following IE script error:
Error:
dialogArguments.___IE_PrintType
is null or not an object.URL:
res://ieframe.dll/preview.dlg
And a small empty print preview dialog appears.
You can print from the command line using the following:
rundll32.exe %WINDIR%\System32\mshtml.dll,PrintHTML "%1"
Where %1 is the file path of the HTML file to be printed.
If you don't need to print from memory (or can afford to write to the disk in a temp file) you can use:
using (Process printProcess = new Process())
{
string systemPath = Environment.GetFolderPath(Environment.SpecialFolder.System);
printProcess.StartInfo.FileName = systemPath + @"\rundll32.exe";
printProcess.StartInfo.Arguments = systemPath + @"\mshtml.dll,PrintHTML """ + fileToPrint + @"""";
printProcess.Start();
}
N.B. This only works on Windows 2000 and above I think.