Internet explorer crash or freezes on BHO execution.

EDN Admin · Jul 20, 2012

Hi,

I have created a BHO using c# to print the label using the value from the web service.
The Internet Explorer crashes after 3 - 4 times of printing an order.
Please help me to overcome this. I want to stop IE crashing , without uninstalling the BHO.
Pasted the full code used.
using System; 
using System.Collections.Generic; 
using System.Text; 
using SHDocVw; 
using mshtml; 
using System.Runtime.InteropServices; 
using Microsoft.Win32; 
using System.IO; 
using System.Reflection; 
using System.Diagnostics; 
using System.Drawing; 
using System.Drawing.Printing; 
using System.Threading; 
using Microsoft.Win32.SafeHandles; 
using System.Management; 
using System.Net.Sockets; 
using ClientPrint_Test.LabelService; 
 
[ComVisible(true), 
Guid("BA0C1A9A-78E7-11E1-AC1E-E8CE4724019B"), 
ClassInterface(ClassInterfaceType.None)] 
 
 
public class CPrinter : IObjectWithSite 
{ 
[DllImport("Kernel32.dll")] 
static extern IntPtr CreateFile( 
string filename, 
[MarshalAs(UnmanagedType.U4)]FileAccess fileaccess, 
[MarshalAs(UnmanagedType.U4)]FileShare fileshare, 
int securityattributes, 
[MarshalAs(UnmanagedType.U4)]FileMode creationdisposition, 
int flags, 
IntPtr template); 
 
// HRESULT values used 
const int E_FAIL = unchecked((int)0x80004005); 
const int E_NOINTERFACE = unchecked((int)0x80004002); 
 
// threading and synchronization 
private ManualResetEvent m_evCreateService = new ManualResetEvent(false); 
 
private IWebBrowser2 webBrowser; 
protected DWebBrowserEvents2_Event m_pDWebBrowserEvents2; 
private Thread PrintLabel; 
 
private string url; 
private int shipmentID; 
private int isMultiple; 
private byte[] currentLabel; 
 
public void SetSite(object site) 
{ 
if (m_pDWebBrowserEvents2 != null) 
{ 
Release(); 
} 
 
webBrowser = site as WebBrowser; 
if (!(webBrowser.FullName.ToUpper().EndsWith("IEXPLORE.EXE"))) 
{ 
Release(); 
return; 
} 
 
m_pDWebBrowserEvents2 = webBrowser as DWebBrowserEvents2_Event; 
 
if (m_pDWebBrowserEvents2 != null) 
{ 
m_pDWebBrowserEvents2.DocumentComplete += new DWebBrowserEvents2_DocumentCompleteEventHandler(webBrowser_DownloadComplete); 
} 
else 
{ 
Release(); 
return; 
} 
 
} 
 
public void webBrowser_DownloadBegin() 
{ 
 
} 
 
public void webBrowser_DownloadComplete(object pDisp, ref object URL) 
{ 
try 
{ 
if (Marshal.Equals(webBrowser, pDisp)) 
{ 
 
HTMLDocument doc = webBrowser.Document as HTMLDocument; 
IHTMLElement el = null; 
 
// Collect the URL 
string strDocumentURL = doc.url; 
string strShipmentID = string.Empty; 
 
// IF URL is not blank then only go ahead 
if (strDocumentURL != string.Empty) 
{ 
// if the URL contains name of the page PrintingLabel.aspx, the take the Shipment ID from it 
if (strDocumentURL.Contains("LabelPrinting/PrintingLabel.aspx")) 
{ 
// split the string to Get the ID 
string[] stringSeparators = new string[] { "?id=" }; 
string[] strArray = strDocumentURL.Split(stringSeparators, StringSplitOptions.RemoveEmptyEntries); 
if (strArray.Length == 2) 
{ 
//strShipmentID = strArray[1]; 
string[] strSeparators = new string[] { "&isMultiple=" }; 
 
string[] strSplittedArray = strArray[1].Split(strSeparators, StringSplitOptions.RemoveEmptyEntries); 
if (strSplittedArray.Length == 2) 
{ 
strShipmentID = strSplittedArray[0]; 
shipmentID = Convert.ToInt32(strSplittedArray[0]); 
isMultiple = Convert.ToInt32(strSplittedArray[1]); 
} 
} 
else 
{ 
// set the 00 as Shipment ID 
strShipmentID = "000000000"; 
shipmentID = 0; 
isMultiple = 0; 
} 
 
int length = doc.url.Substring(0, doc.url.LastIndexOf(/)).LastIndexOf(/) + 1; 
this.url = doc.url.Substring(0, length) + "webservices/LabelWebService.asmx"; 
 
PrintLabel = new Thread(this.PrintForCompleteShipment); 
PrintLabel.SetApartmentState(ApartmentState.STA); 
PrintLabel.Start(); 
} 
} 
} 
 
} 
catch (Exception ex) 
{ 
Release(); 
Marshal.ThrowExceptionForHR(E_FAIL); 
} 
} 
 
 
public void GetSite(ref Guid guid, out IntPtr ppvSite) 
{ 
 
ppvSite = IntPtr.Zero; 
if (webBrowser != null) 
{ 
IntPtr pSite = IntPtr.Zero; 
IntPtr punk = Marshal.GetIUnknownForObject(webBrowser); 
Marshal.QueryInterface(punk, ref guid, out pSite); 
Marshal.Release(punk); 
Marshal.Release(punk); 
 
if (!punk.Equals(IntPtr.Zero)) 
{ 
ppvSite = pSite; 
 
}else 
{ 
Release(); 
Marshal.ThrowExceptionForHR(E_NOINTERFACE); 
} 
 
} else 
{ 
Release(); 
Marshal.ThrowExceptionForHR(E_FAIL); 
} 
} 
 
public static string BHOKEYNAME = "Software\Microsoft\Windows\CurrentVersion\Explorer\Browser Helper Objects"; 
 
[ComRegisterFunction] 
public static void RegisterBHO(Type type) 
{ 
RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(BHOKEYNAME, true); 
 
if (registryKey == null) 
registryKey = Registry.LocalMachine.CreateSubKey(BHOKEYNAME); 
 
string guid = type.GUID.ToString("B"); 
RegistryKey ourKey = registryKey.OpenSubKey(guid); 
 
if (ourKey == null) 
ourKey = registryKey.CreateSubKey(guid); 
 
ourKey.SetValue("ClientPrint_Test", 1); 
registryKey.Close(); 
ourKey.Close(); 
} 
 
[ComUnregisterFunction] 
public static void UnregisterBHO(Type type) 
{ 
RegistryKey registryKey = Registry.LocalMachine.OpenSubKey(BHOKEYNAME, true); 
string guid = type.GUID.ToString("B"); 
 
if (registryKey != null) 
registryKey.DeleteSubKey(guid, false); 
} 
 
protected void Release() 
{ 
if (m_pDWebBrowserEvents2 != null) 
{ 
Marshal.ReleaseComObject(m_pDWebBrowserEvents2); 
m_pDWebBrowserEvents2 = null; 
Array.Clear(currentLabel, 0, currentLabel.Length); 
} 
if (webBrowser != null) 
{ 
Marshal.ReleaseComObject(webBrowser); 
webBrowser = null; 
Array.Clear(currentLabel, 0, currentLabel.Length); 
} 
} 
 
 
public void PrintForCompleteShipment() 
{ 
try 
{ 
byte[][] labels = null; 
byte[][] returnLabels = null; 
LabelWebService labelService = new LabelWebService(); 
if (isMultiple == 0) // Not Multiple but with return labels 
{ 
returnLabels = labelService.GetLabelsByShipmentPackage(shipmentID); 
foreach (byte[] inArray in returnLabels) 
{ 
// byte[] inArray = imgData; 
if (inArray != null && inArray.Length > 0) 
{ 
string message = Convert.ToBase64String(inArray); 
this.currentLabel = inArray; 
PrintDocument printDocument = new PrintDocument(); 
printDocument.PrinterSettings = new PrinterSettings(); 
printDocument.PrinterSettings.PrinterName = this.DeterminePrinterName(); 
printDocument.PrintPage += new PrintPageEventHandler(this.pd_PrintPage); 
printDocument.Print(); 
 
 
} 
} 
 
 
} 
else // for Multiple records 
{ 
labels = labelService.GetLabels(shipmentID); 
foreach (byte[] inArray in labels) 
{ 
// byte[] inArray = imgData; 
if (inArray != null && inArray.Length > 0) 
{ 
string message = Convert.ToBase64String(inArray); 
this.currentLabel = inArray; 
PrintDocument printDocument = new PrintDocument(); 
printDocument.PrinterSettings = new PrinterSettings(); 
printDocument.PrinterSettings.PrinterName = this.DeterminePrinterName(); 
printDocument.PrintPage += new PrintPageEventHandler(this.pd_PrintPage); 
printDocument.Print(); 
 
} 
} 
 
} 
} 
catch (Exception ex) 
{ 
 
} 
 
} 
 
private string DeterminePortName() 
{ 
string returnValue = null; 
 
ManagementObjectSearcher s = new ManagementObjectSearcher("SELECT * FROM Win32_Printer"); 
ManagementObjectCollection col = s.Get(); 
 
foreach (ManagementObject printer in col) 
{ 
if ((bool)printer["Default"]) 
{ 
returnValue = (string)printer["PortName"]; 
} 
} 
return returnValue; 
} 
 
private string DeterminePrinterName() 
{ 
string str = (string)null; 
foreach (ManagementObject managementObject in new ManagementObjectSearcher("SELECT * FROM Win32_Printer").Get()) 
{ 
if ((bool)managementObject["Default"]) 
str = managementObject.Path.RelativePath.Replace("Win32_Printer.DeviceID=", string.Empty); 
} 
return str.Replace(""", string.Empty); 
} 
 
private void pd_PrintPage(object sender, PrintPageEventArgs ev) 
{ 
 
int height = 600; 
int width = 400; 
int x = 3; 
int y = 3; 
 
try 
{ 
MemoryStream memoryStream = new MemoryStream(this.currentLabel, 0, this.currentLabel.Length); 
memoryStream.Write(this.currentLabel, 0, this.currentLabel.Length); 
Image image = Image.FromStream((Stream)memoryStream); 
if (image.Height == 1200) 
ev.Graphics.DrawImage(image, x, y, width, height); 
else if (image.Height == 800) 
ev.Graphics.DrawImage(image, 10, 10, 591, 392); 
else 
ev.Graphics.DrawImage(image, 3, 3, 400, 600); 
ev.HasMorePages = false; 
memoryStream.SetLength(0); 
memoryStream.Close(); 
image.Dispose(); 
 
} 
catch(Exception ex) 
{ 
 
} 
} 
 
} 

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Internet explorer crash or freezes on BHO execution.

EDN Admin

Well-known member

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