I am receiving the following error message in a non-reproducable and seemingly random fashion in my ASP.NET, C# application:
System.AccessViolationException was unhandled
Message: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
The only steps I can take to reproduce the error are to run the offending function many times, and at some point, this error occurs.
The function that I believe to be causing the error is as follows (well, actually I think that GDI+ using this functions output is the cause):
public static Font GetFont(HttpServerUtility Server, string FontName, int Size, bool Admin)
{
//Check if it's in the PrivateFontCollection
//If not then it is a system font
PrivateFontCollection pfc = null;
if (Admin)
{
pfc = IO.GetFonts(Server.MapPath("../Fonts/"));
}
else
{
pfc = IO.GetFonts(Server.MapPath("Fonts/"));
}
int count = pfc.Families.Length;
for (int j = 0; j < count; ++j)
{
// Get the font family name.
string familyName = pfc.Families[j].Name;
if (familyName.ToLower() == FontName.ToLower())
{
Font fx = new Font(pfc.Families[j], (float)Size);
return fx;
}
}
Font f = new Font(FontName, Size);
return f;
}
The aim of this function is to use a font name, say "Arial" as an example. "Arial" is passed to the function which then cycles through a PrivateFontCollection to determine if it is present in the private collection, or whether the font specified is a system font. The function IO.GetFonts(Server.MapPath("Fonts/")) is as follows:
public static System.Drawing.Text.PrivateFontCollection GetFonts(string Path)
{
string FontFilesLocation = Path;
System.Drawing.Text.PrivateFontCollection pf;
string[] ttfs;
System.Drawing.FontFamily ff;
pf = new System.Drawing.Text.PrivateFontCollection();
ttfs = System.IO.Directory.GetFiles(FontFilesLocation, "*.ttf");
for (int i = 0; i < ttfs.Length; i++)
{
try
{
pf.AddFontFile(ttfs
);
}
catch (Exception)
{
}
}
return pf;
}
This is designed to simply build the PrivateFontCollection from the specified path.
When the error occurs, two events are written into the event log:
1.)aspnet_wp.exe (PID: 2780) stopped unexpectedly.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
and
2.) Event Type: Error
Event Source: .NET Runtime 2.0 Error Reporting
Event Category: None
Event ID: 1000
Date: 08/04/2006
Time: 19:29:52
User: N/A
Computer: MARTIN
Description:
Faulting application aspnet_wp.exe, version 2.0.50727.42, stamp 4333aece, faulting module gdiplus.dll, version 5.1.3102.2180, stamp 4110968b, debug? 0, fault address 0x00046fc6.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.
Data:
0000: 41 00 70 00 70 00 6c 00 A.p.p.l.
0008: 69 00 63 00 61 00 74 00 i.c.a.t.
0010: 69 00 6f 00 6e 00 20 00 i.o.n. .
0018: 46 00 61 00 69 00 6c 00 F.a.i.l.
0020: 75 00 72 00 65 00 20 00 u.r.e. .
0028: 20 00 61 00 73 00 70 00 .a.s.p.
0030: 6e 00 65 00 74 00 5f 00 n.e.t._.
0038: 77 00 70 00 2e 00 65 00 w.p...e.
0040: 78 00 65 00 20 00 32 00 x.e. .2.
0048: 2e 00 30 00 2e 00 35 00 ..0...5.
0050: 30 00 37 00 32 00 37 00 0.7.2.7.
0058: 2e 00 34 00 32 00 20 00 ..4.2. .
0060: 34 00 33 00 33 00 33 00 4.3.3.3.
0068: 61 00 65 00 63 00 65 00 a.e.c.e.
0070: 20 00 69 00 6e 00 20 00 .i.n. .
0078: 67 00 64 00 69 00 70 00 g.d.i.p.
0080: 6c 00 75 00 73 00 2e 00 l.u.s...
0088: 64 00 6c 00 6c 00 20 00 d.l.l. .
0090: 35 00 2e 00 31 00 2e 00 5...1...
0098: 33 00 31 00 30 00 32 00 3.1.0.2.
00a0: 2e 00 32 00 31 00 38 00 ..2.1.8.
00a8: 30 00 20 00 34 00 31 00 0. .4.1.
00b0: 31 00 30 00 39 00 36 00 1.0.9.6.
00b8: 38 00 62 00 20 00 66 00 8.b. .f.
00c0: 44 00 65 00 62 00 75 00 D.e.b.u.
00c8: 67 00 20 00 30 00 20 00 g. .0. .
00d0: 61 00 74 00 20 00 6f 00 a.t. .o.
00d8: 66 00 66 00 73 00 65 00 f.f.s.e.
00e0: 74 00 20 00 30 00 30 00 t. .0.0.
00e8: 30 00 34 00 36 00 66 00 0.4.6.f.
00f0: 63 00 36 00 0d 00 0a 00 c.6.....
In that stack trace there is a clear reference to gdiplus.dll, which is using the output of the font function in the following way (g is a graphics object - created from a bitmap that was created from a PNG):
Font f = GetFont(Server, font, int.Parse(size), false);
g.DrawString(defaultText, f, brush, drawRect, drawFormat);
So, I am assuming that it is either that DrawString method that is causing the problem, or the Font assignment. This did not happen before I wrote the above two functions. I really need the private font support so any help would be greatly appreciated.
Attempted to read or write protected memory - Fonts
