Using MARS or There is already an open DataReader associated with this Command which must be closed first.

14. December 2011 10:11 by Mrojas in   //  Tags: , , , , ,   //   Comments (0)


This is a very strange error that you can find sometimes when working with ADO.NET.

David McKean from MSFT says:

This occurs when you have multiple DataReaders open concurrently on the same connection,
ie you call SqlCommand.ExecuteReader but don't close the SqlDataReader returned by this
method before calling it again (either on the same command or another command on the same connection).

It requires a feature called MultipleActiveResultSets which is not available in all providers.

For example SQL2000 does not support it, it was implemented starting from SQL2005.

Also .NET 2.0 must be used.

For more information about enabling Multiple Active Result Sets see:

A good recommendation to make sure that the the readers are closed is to put them inside a using statement, in that case,
no matter if an exception happened they will be closed and disposed.

If you are using SQL Server 2000, MARS is not available so you can create two different connection objects.

Another good article about this issue is:


But in general to use it is just a change in the connection string:

    <clear />
      <add name="VasquezDB" 
         connectionString="Data Source=rvasquez;Initial Catalog=VasquezDB;
                 Integrated Security=True;MultipleActiveResultSets=Yes" />


Good Luck


NOTE: a good link with more details about MARS is:

Property Pages in VB.NET and C#

13. September 2011 02:20 by Mrojas in General  //  Tags: , , , , , ,   //   Comments (0)

Visual Basic 6.0 property pages allow you to work around the
limitations of the Visual Basic Property Browser. For example,
you can use property pages to give users a way to add a collections of
colors to a color list user control.

In the property page you would write code that manages the collection,
something beyond the capabilities of the Visual Basic Property Browser.
In contrast, the Visual Basic .NET Property Browser can be used
to edit any .NET variable type or class. Property Pages are no longer needed.

The Upgrade Wizard and the VBUC do not automatically upgrade your
Visual Basic 6.0 property pages but they can sure be of help.
What if you really what to keep those property pages? Is there any workaround.
mmmm Sure there is.

You can follow these steps.

1. Before migrating your Visual Basic 6.0 project with the VBUC
modify your property pages (.pag) files to resemble common Visual Basic 6.0 forms.
For example a property page looks like this:

Begin VB.PropertyPage PropertyPage1 
   Caption         =   "PropertyPage1"
   ClientHeight    =   3600
   ClientLeft      =   0
   ClientTop       =   0
   ClientWidth     =   4800
   PaletteMode     =   0  'Halftone
   ScaleHeight     =   3600
   ScaleWidth      =   4800
   Begin VB.TextBox Text1 
      Height          =   495
      Left            =   480
      TabIndex        =   1
      Text            =   "Text1"
      Top             =   1200
      Width           =   2175
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   615
      Left            =   3120
      TabIndex        =   0
      Top             =   480
      Width           =   1455
   Begin VB.Label Label1 
      Caption         =   "Label1"
      Height          =   375
      Left            =   240
      TabIndex        =   2
      Top             =   600
      Width           =   1815
Attribute VB_Name = "PropertyPage1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False

Can be turned into a Form, to ease migration with simple changes:

Begin VB.Form  PropertyPage1 
   Caption         =   "PropertyPage1"
   ClientHeight    =   3600
   ClientLeft      =   0
   ClientTop       =   0
   ClientWidth     =   4800
   PaletteMode     =   0  'Halftone
   ScaleHeight     =   3600
   ScaleWidth      =   4800
   Begin VB.TextBox Text1 
      Height          =   495
      Left            =   480
      TabIndex        =   1
      Text            =   "Text1"
      Top             =   1200
      Width           =   2175
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   615
      Left            =   3120
      TabIndex        =   0
      Top             =   480
      Width           =   1455
   Begin VB.Label Label1 
      Caption         =   "Label1"
      Height          =   375
      Left            =   240
      TabIndex        =   2
      Top             =   600
      Width           =   1815
Attribute VB_Name = "PropertyPage1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False

If the form had a event like:

Private Sub PropertyPage_Initialize()

End Sub

Change that to Form_Load()

2. Rename the file from .pag to .frm.
3. Remove the .pag from the VB6 project
4. Add the .frm file to the VB6 project
5. Run the VBUC tool.

Once migrated you have a close migration of your original Property Page.
Remember however that some things change in .NET and you will need to manually finish some details.
For example, you need to review code in the
PropertyPage_EditProperty(PropertyName As String)

Ok. Once you take your Property Page to .NET how do you integrate it with your control.
Well that’s easy. There you could create a ControlDesigner or just use an UITypeEditor.

Let’s see the UITypeEditor aproach.

The general idea with this aproach is to provide an UITypeEditor (this is just a way to provide an
editor in the property Browser that is not supported by default. And taking advantage of that editor
we will show the form that was produced after migrating out Property Pages. If you want an interface
more similar to what you had on Visual Basic 6.0 you can modify the property page and add a TabControl.

Ok. So these are the steps to follow:

1. First you need to create a type for which you will provide a Type Editor. We will call this type CustomData


namespace CustomEditor
    public class CustomData

2.Now we will add a property to our control.

        public CustomData Custom

3. Now add attributes to associate an editor

        [Description("Custom"), Editor(typeof(CustomDataEditor), typeof(UITypeEditor))]
        public CustomData Custom

4. And now lets implement the CustomDataEditor

using System.Windows.Forms.Design;

namespace CustomEditor
    public class CustomDataEditor : UITypeEditor
        public CustomDataEditor() {}

        public override UITypeEditorEditStyle GetEditStyle(System.ComponentModel.ITypeDescriptorContext context)

            return UITypeEditorEditStyle.Modal;

        public override object EditValue(System.ComponentModel.ITypeDescriptorContext context, IServiceProvider provider, object value)
            IWindowsFormsEditorService frmsvr = (IWindowsFormsEditorService)provider.GetService(typeof(IWindowsFormsEditorService));
            if (frmsvr == null) return null;
            PropertyPageForm propPage = new PropertyPageForm();
            propPage.control = (MyControl)context.Instance;
            return null;


5. In the previous put attention to the highlighted details. What we are doing is getting a reference
to the WindowsFormEditor service so we property open the PropertyPage that has now been turned into a form.
It is important that you add a public property to the migrated PropertyPage like:

public MyControl control { get; set; };

because that will give you a reference to the actual control that is on the form. The property page is just an interface
you will need to set the values into properties on your control, in order for them to be serialized.

6. Once you do that, when you see the property editor for your control you will see something like:

When you press the … button it will show up your property page form.

You could also add other visual elements like:


But that is maybe for another post.


Setting the Default Printer in .NET

The following C# code shows how to use WMI to query printers information, set and get default printer.
public bool SetDefaultPrinter()
    System.Management.ManagementObjectSearcher search = 
default(System.Management.ManagementObjectSearcher); System.Management.ManagementObjectCollection results =
default(System.Management.ManagementObjectCollection); System.Management.ManagementObject printer =
default(System.Management.ManagementObject); search =
new System.Management.ManagementObjectSearcher("select * from win32_printer"); results = search.Get(); //Get Default Printer System.Management.ManagementObject defaultPrinter = null; foreach (System.Management.ManagementObject foundPrinter in results) { System.Management.PropertyDataCollection
propertyDataCollection = foundPrinter.Properties; if ((bool)foundPrinter["Default"]) // DEFAULT PRINTER { System.Diagnostics.Debug.WriteLine(foundPrinter["Name"]); System.Diagnostics.Debug.WriteLine(foundPrinter["Location"]); } } //Sets new default Printer foreach (System.Management.ManagementObject foundPrinter in results) { System.Diagnostics.Debug.Print(foundPrinter["Name"].ToString()); if (foundPrinter["Name"].Equals("PDFCreator")) { System.Management.ManagementBaseObject outParams =
foundPrinter.InvokeMethod("SetDefaultPrinter", null, null); if (outParams == null) System.Diagnostics.Debug.WriteLine("Unable to set default printer"); Int32 retVal = (int)(uint)outParams.Properties["ReturnValue"].Value; if (retVal == 0) return true; else return false; } } return false; }

Control Property Serialization in .NET

While solving a bug with a custom class that extended the System.Data.DataSet class, I found a situation where the class implemented, the ISerializable interface, but for some reason, during the call to the base.GetObjectData in my serialization code it was trying to get the value of some properties that caused an exception.

The reason was that those properties were not “ready” because my serialization code had not finish initializing the object. But why was the Dataset.GetObjectData trying to get or set those values.

It seems that there is some code in the dataset that used reflection to get the object properties and try to serialize them. I did not want that.
How could I stop the framework from doing that?

I thought of the NonSerializable attribute but that works only on fields and what I have is a property.

I thought of the XmlIgnore attribute but it had no effect.


Well I finally found that you can add a couple of (not attributes) methods to your component.

They should be named Reset<Property>() and ShouldSerialize<Property>() and returning a boolean value
from these functions will control if the properties are serialized or not.

For more info see MSDN page for ShouldSerialize

Determine is executable is a console application

30. November 2010 03:36 by Mrojas in General  //  Tags: , ,   //   Comments (0)


I you were looking for a way to do that just take a look at this post:

Just notice that for this post you need to add this struct:

public struct SHFILEINFO
  public IntPtr hIcon;
  public IntPtr iIcon;
  public uint dwAttributes;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 260)]
  public string szDisplayName;
  [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 80)]
  public string szTypeName;

IIS 6 Metabase and IIS 6 Configuration Compatibility

11. November 2010 04:38 by Mrojas in General  //  Tags: , , , ,   //   Comments (0)


I have a silverlight application that I was trying to publish from Visual Studio to my local IIS and I got this problem:

For the record I have Windows 7.



So you can write on the Search program and Files “ Turn Windows Features on or off”




And then select



Where is my DXCore

19. August 2009 05:06 by Mrojas in General  //  Tags: , , , ,   //   Comments (0)

I’m an enthusiastic user of DXCore and I have been working on some extensions of my own. But I could not find the DXCore or DevExpress menu.

Well there is a hack for that.

Please invoke the Registry editor, add the "HideMenu" DWORD value to the following Registry key, and set its Value to 0:
HKEY_LOCAL_MACHINE\SOFTWARE\Developer Express\CodeRush for VS\9.1
This should make the "DevExpress" menu visible.

Look at the post for more details and keep enjoying DXCore.

Migration from .NET Framework 1.1

13. August 2009 18:07 by Mrojas in General  //  Tags: , , , , , ,   //   Comments (0)

.NET has been around for quite a while. According Wikipedia it has been around since on 3 April 2003
So now there exist applications developed for .NET Framework 1.0 or 1.1 and people
need to migrate them to Framework 2.0 or Framework 3.5.

It is the general impression that there is not a direct path to 3.5.
As Zain Naboulsi explains in his blog you can go from 1.1 to 2.0 then from 2.0 to 3.5.
And From 2.0 to 3.5 the migration is a no-brainer because, both, 3.0 and 3.5 are based on 2.0.

A good reference also is the post of Peter Laudati on migration from 1.1 to 2.0.
Note: Peter’s post seem to have a broken link to the microsoft document about breaking changes in 2.0.
The correct link is this.

A more recent post by The Moth provides more links to breaking changes documents:

- Design time Breaking Changes in .NET Framework 2.0
- Runtime Breaking Changes in .NET Framework 2.0
- Microsoft .NET Framework 1.1 and 2.0 Compatibility
- Compatibility Testing Scenarios

Going from 1.1 to 2.0 or 3.5 can be just as simple as opening the solution in VS and compile
or it can take a lot of effort. Web Projects then to be more difficult due to several changes in ASP.NET.

So good luck.


Well there a lot of static analyisis tools we have used
(some internal, some from Third Parties. I particulary like Understand and NDepend)

CapsLock, NumLock in C# and VB.NET

10. July 2009 12:49 by Mrojas in General  //  Tags: , , , , ,   //   Comments (0)

I was looking for a “.net” way of detecting the CapsLock state, but almost all the references pointed to pinvoke code like:

<DllImport("user32.dll")> _
Public Shared Function GetKeyState(VirtKey As Integer) As Integer
End Sub

And I finally found two ways:

1) You can call methods from the System.Console class:

You can use the System.Console.CapsLock property and if you want the NumLock state use: System.Console.NumberLock


2) You can call make an instance of Microsoft.VisualBasic.Devices.Keyboard. (For this if you are in C# you need to add a reference to Microsoft.VisualBasic.dll)

For example:

Microsoft.VisualBasic.Devices.Keyboard key = new Microsoft.VisualBasic.Devices.Keyboard();

and use properties like:







Printing RichTextBox contents in C#

10. July 2009 05:54 by Mrojas in General  //  Tags: , , , ,   //   Comments (0)

This post discusses and provides the implementation of a helper class to add support
for printing the formatted contents of a richtextbox control.

The print model in .NET is a little different than one used in VB6.

For example see:

Public Sub PrintRTF(RTF As RichTextBox, LeftMarginWidth As Long, _
   TopMarginHeight, RightMarginWidth, BottomMarginHeight)
   Dim LeftOffset As Long, TopOffset As Long
   Dim LeftMargin As Long, TopMargin As Long
   Dim RightMargin As Long, BottomMargin As Long
   Dim fr As FormatRange
   Dim rcDrawTo As Rect
   Dim rcPage As Rect
   Dim TextLength As Long
   Dim NextCharPosition As Long
   Dim r As Long

   ' Start a print job to get a valid Printer.hDC
   Printer.Print Space(1)
   Printer.ScaleMode = vbTwips

   ' Get the offsett to the printable area on the page in twips
   LeftOffset = Printer.ScaleX(GetDeviceCaps(Printer.hdc, _
      PHYSICALOFFSETX), vbPixels, vbTwips)
   TopOffset = Printer.ScaleY(GetDeviceCaps(Printer.hdc, _
      PHYSICALOFFSETY), vbPixels, vbTwips)

   ' Calculate the Left, Top, Right, and Bottom margins
   LeftMargin = LeftMarginWidth - LeftOffset
   TopMargin = TopMarginHeight - TopOffset
   RightMargin = (Printer.Width - RightMarginWidth) - LeftOffset
   BottomMargin = (Printer.Height - BottomMarginHeight) - TopOffset

   ' Set printable area rect
   rcPage.Left = 0
   rcPage.Top = 0
   rcPage.Right = Printer.ScaleWidth
   rcPage.Bottom = Printer.ScaleHeight

   ' Set rect in which to print (relative to printable area)
   rcDrawTo.Left = LeftMargin
   rcDrawTo.Top = TopMargin
   rcDrawTo.Right = RightMargin
   rcDrawTo.Bottom = BottomMargin

   ' Set up the print instructions
   fr.hdc = Printer.hdc   ' Use the same DC for measuring and rendering
   fr.hdcTarget = Printer.hdc  ' Point at printer hDC
   fr.rc = rcDrawTo            ' Indicate the area on page to draw to
   fr.rcPage = rcPage          ' Indicate entire size of page
   fr.chrg.cpMin = 0           ' Indicate start of text through
   fr.chrg.cpMax = -1          ' end of the text

   ' Get length of text in RTF
   TextLength = Len(RTF.Text)

   ' Loop printing each page until done
      ' Print the page by sending EM_FORMATRANGE message
      NextCharPosition = SendMessage(RTF.hWnd, EM_FORMATRANGE, True, fr)
      If NextCharPosition >= TextLength Then Exit Do  'If done then exit
      fr.chrg.cpMin = NextCharPosition ' Starting position for next page
      Printer.NewPage                  ' Move on to next page
      Printer.Print Space(1) ' Re-initialize hDC
      fr.hdc = Printer.hdc
      fr.hdcTarget = Printer.hdc

   ' Commit the print job

   ' Allow the RTF to free up memory
   r = SendMessage(RTF.hWnd, EM_FORMATRANGE, False, ByVal CLng(0))
End Sub

The VBCompanion provides excellent helpers that provide a lot fo the VB6 Printer object functionality, so you dont have to change any of your actual code, but in some cases, you might just want to remove that code, specially for very specific things like printing a RichTextBox.

So here I’m providing a .NET simplified helper that allows you to print the contents of a RichTextBox control. This helper is just based on the code published by Martin Muller in It provides an extension method for VS 2008 user so all you have to do is call RichTextBox.Print.

The implementation is simple. The RichTextBoxPrintHelper creates or receives an instance of a PrintDocument object, and event handlers are added to it for the BeginPrint, PrintPage and EndPrint events.

    private int m_nFirstCharOnPage;

    private void printDocument_BeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
        // Start at the beginning of the text
        m_nFirstCharOnPage = 0;

    private void printDocument_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
        // To print the boundaries of the current page margins
        // uncomment the next line:
        //e.Graphics.DrawRectangle(System.Drawing.Pens.Blue, e.MarginBounds);

        // make the RichTextBoxEx calculate and render as much text as will
        // fit on the page and remember the last character printed for the
        // beginning of the next page
        m_nFirstCharOnPage = FormatRange(false,

        // check if there are more pages to print
        if (m_nFirstCharOnPage < control.TextLength)
            e.HasMorePages = true;
            e.HasMorePages = false;

    private void printDocument_EndPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
        // Clean up cached information
The FormatRange method is called. This method will use the fill out some structures 
with page information and use the RichTextBox handle to send messages that will render
the control contents to the Printer’s HDC.
 /// <summary>
    /// Calculate or render the contents of our RichTextBox for printing
    /// </summary>
    /// <param name="measureOnly">If true, only the calculation is performed,
    /// otherwise the text is rendered as well</param>
    /// <param name="e">The PrintPageEventArgs object from the
    /// PrintPage event</param>
    /// <param name="charFrom">Index of first character to be printed</param>
    /// <param name="charTo">Index of last character to be printed</param>
    /// <returns>(Index of last character that fitted on the
    /// page) + 1</returns>
    public int FormatRange(bool measureOnly, PrintPageEventArgs e,
        int charFrom, int charTo)
        // Specify which characters to print
        cr.cpMin = charFrom;
        cr.cpMax = charTo;

        // Specify the area inside page margins
        STRUCT_RECT rc; = HundredthInchToTwips(e.MarginBounds.Top);
        rc.bottom = HundredthInchToTwips(e.MarginBounds.Bottom);
        rc.left = HundredthInchToTwips(e.MarginBounds.Left);
        rc.right = HundredthInchToTwips(e.MarginBounds.Right);

        // Specify the page area
        STRUCT_RECT rcPage; = HundredthInchToTwips(e.PageBounds.Top);
        rcPage.bottom = HundredthInchToTwips(e.PageBounds.Bottom);
        rcPage.left = HundredthInchToTwips(e.PageBounds.Left);
        rcPage.right = HundredthInchToTwips(e.PageBounds.Right);

        // Get device context of output device
        IntPtr hdc = e.Graphics.GetHdc();

        // Fill in the FORMATRANGE struct
        fr.chrg = cr;
        fr.hdc = hdc;
        fr.hdcTarget = hdc;
        fr.rc = rc;
        fr.rcPage = rcPage;

        // Non-Zero wParam means render, Zero means measure
        Int32 wParam = (measureOnly ? 0 : 1);

        // Allocate memory for the FORMATRANGE struct and
        // copy the contents of our struct to this memory
        IntPtr lParam = Marshal.AllocCoTaskMem(Marshal.SizeOf(fr));
        Marshal.StructureToPtr(fr, lParam, false);

        // Send the actual Win32 message
        int res = SendMessage(control.Handle, EM_FORMATRANGE, wParam, lParam);

        // Free allocated memory

        // and release the device context

        return res;

Using the RichTextBox is even more simple. You add a richtextbox to a form and call the Print method:


        private void printToolStripMenuItem_Click(object sender, EventArgs e)

I’m attaching the source code for the helper an this sample application so you can use this.


VB6 TabIndex and C#

5. June 2009 05:30 by Mrojas in General  //  Tags: , , , , ,   //   Comments (0)

Some time ago Jose Aguilar had blogged about the Interesting Behavior of TabIndex in Migrated Applications. As he explained at the time there are functional differences between the TabIndex behaviour in VB6


If you look at Figure1.


Figure 1. This image show a VB6 form, the TabIndex values and the way the form navigates when you press Tab.

If you migrate that form with the VBUC and activate the TabOrder option in View\TabOrder you will see something like:


As you can see by the 0.1 and 0.3 and 5.4 and 5.2 values. TabOrder in .NET is hierarquical. When you press tab you will navigate to the next control in the container, and when you get to the last in that container then you will switch to the next one in the following container. This is different from the VB6 world when you would have switched from 0.1 to 5.2.

How can we fix this without a lot of manual corrections. Well you can override the ProcessTabKey method to navigate controls following the tabIndex without taking into account the containers.

The code you will need to add is:

        /// <summary>
/// holds a list of controls for tab navigation
/// </summary>
List<Control> controls = new List<Control>();
/// <summary>
/// Populates the list used for tab navigation
/// </summary>
/// <param name="c">Control to use to populate list</param>
protected void BuildOrder(Control c)
if (c.TabStop)
if (c.Controls.Count > 0)
foreach (Control child in c.Controls)
/// <summary>
/// Transversers all form controls to populate a list ordered by TabIndex
/// that will be used to follow tabindex ignoring containers
/// </summary>
protected void BuildOrder()
if (controls.Count == 0)

foreach (Control c in this.Controls)
delegate(Control c1, Control c2) { return c1.TabIndex.CompareTo(c2.TabIndex); });
/// <summary>
/// Overrides default tabIndex behaviour
/// </summary>
/// <param name="forward"></param>
/// <returns></returns>
protected override bool ProcessTabKey(bool forward)
if (ActiveControl != null)
int index = controls.IndexOf(ActiveControl);
if (index != -1)
if (forward)
controls[(index + 1) % controls.Count].Select();

return true;

return false;
return base.ProcessTabKey(forward);

After adding this code just run your project and it will fix the tabIndex issues.

A Better Visual Studio!

3. June 2009 04:21 by Mrojas in General  //  Tags: , , ,   //   Comments (0)

Recently I discovered in MSDN a great addition, a must to for all C# developers. CodeRush Express.

This product was build by DevExpress and it just make it perfect your experience with Visual Studio.


For example finding symbols or files, tabbing between references, and more than 20 differente refactorings!!!!

Take at look at this new extension! It’s a absolutely a must.

Extended WebBrowser Control Series:And the WebBrowser keeps going…

Well recently Kingsley has point me to a lot of useful links to improve the ExtendedWebBrowser. However he found another detail. When in Javascript you do something like a:‘url’,’window’,’width=200;height=300’);

Those width and height settings were not being considered in the new window. I researched for I while until I found this great link:

HOW TO: Get Width and Height from Inside a WebBrowser Host by Using Visual Basic .NET

So basicly I follow the sugested code and added logic in my EventSink class:

        public void WindowSetLeft(int Left)
            ///Should I calculate any diff?
            _Browser.Parent.Left = Left;


        public void WindowSetTop(int Top)
            _Browser.Parent.Top = Top;


        public void WindowSetWidth(int Width)
            int diff = 0;
            diff = _Browser.Parent.Width - _Browser.Width;
            _Browser.Parent.Width = diff + Width;

        public void WindowSetHeight(int Height)
            int diff = 0;
            diff = _Browser.Parent.Height - _Browser.Height;
            _Browser.Parent.Height = diff + Height;

So now when the window opens it takes the specified width, heigth, left and top.

As always


Extended WebBrowser Control Series: WebBrowser Control and window.Close()

I had previously posted an extended version of the WebBrowser Control. This code posted in Opening Popup in a NewWindow and NewWindow2 Events in the C# WebBrowserControl, dealt with some issues when you want to have a form with a WebBrowser and in the enclosed page you have a Javascript code like:“ <some url to a page”)

But recently another problem arised. What if you have a Javascript snippet like:


OMG!!! Why haven’t I thought about it. Well Kelder wrote me about this problem and he also sent me some of his\her research results:

Solution (Add WebBrowser as unmanaged code):

Solution (Add WebBrowser using WM_NOTIFYPARENT override)

Solution (Implementation not detailed):

Proposes changing pop-up links to WebBrowser navigate:

problem observed (no solution)

It seams to me that the better solution is to use jpsanders solution, so I created an ExtendWebBrowser_v2 (the following is the modified fragment):

//Extend the WebBrowser control
public class ExtendedWebBrowser : WebBrowser
    // Define constants from winuser.h
    private const int WM_PARENTNOTIFY = 0x210;
    private const int WM_DESTROY = 2;
    AxHost.ConnectionPointCookie cookie;
    WebBrowserExtendedEvents events;

    protected override void WndProc(ref Message m)
        switch (m.Msg)
            case WM_PARENTNOTIFY:
             if (!DesignMode) 
                if (m.WParam.ToInt32() == WM_DESTROY) 
                    Message newMsg = new Message();
                    newMsg.Msg = WM_DESTROY;
                    // Tell whoever cares we are closing
                    Form parent = this.Parent as Form;
                    if (parent!=null)
            DefWndProc(ref m);
            base.WndProc(ref m);

The problem that might arise with this solution is that the parent might not be a Form but an user control, etc. For a more general aproach I think I should send a WM_DESTROY directly to the parent, but for most cases it works. I’m attaching the code and a sample page called test0.htm. I hope this helps and rembember you can always donate to programming geeks jejejejeje just kidding


Get the Week Number in C#

30. April 2009 10:56 by Mrojas in General  //  Tags: , , ,   //   Comments (0)

Here is some examples of how to determine the WeekNumber of a given Date

using System;
using System.Collections.Generic;
using System.Text;

namespace ConsoleApplication1
    class Program
        static void Main(string[] args)

        object index = DateTime.Now;
        int res = 0;
        //0    First day of year
        res = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
        Convert.ToDateTime(index), System.Globalization.CalendarWeekRule.FirstDay, System.Globalization.DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek);

        //1    (Default) First four day week from Sunday
        res = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
        Convert.ToDateTime(index), System.Globalization.CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Sunday);

        //2    First four day week from StartOfWeek
        res = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
                Convert.ToDateTime(index), System.Globalization.CalendarWeekRule.FirstFourDayWeek, System.Globalization.DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek);

        //3    First full week from Sunday
        res = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
                Convert.ToDateTime(index), System.Globalization.CalendarWeekRule.FirstFullWeek, DayOfWeek.Sunday);
        //4    First full week from StartOfWeek
        res = System.Globalization.CultureInfo.CurrentCulture.Calendar.GetWeekOfYear(
                Convert.ToDateTime(index), System.Globalization.CalendarWeekRule.FirstFullWeek, System.Globalization.DateTimeFormatInfo.CurrentInfo.FirstDayOfWeek);


Bittable What????

As vb6 migration experts in our company we deal everyday with a lot of issues around Interop and serialization.

One important thing to note is the concept of “Bittable Types”. I’m not making up terms. Those terms actually exist. Just see this link in MSDN.

In a few words, a bittable type is a type that has the same representation in managed and unmanaged code.

Why in earth is that important at all?

Because if you are calling that great C++ DLL implemented some years ago that just works ok, you won’t be able to pass a NON-Bittable type because that DLL will expect a binary representation different from that in the .NET virtual machine.

This is also an issue in other scenarios like:

  • Serializing content to files
  • Sending messages through messaging mechanisms like named-pipes or sockets.

Well, we have just introduced the problem so now let’s think on a nice solution for this problem.

Well Bittable Types are:

The following types from the System namespace are blittable types:


So now let’s look at a couple of non-BITTABLE types


To test this differences let’s make a small test in VB6 and write a Date value to a file:


Private Sub SaveDateToFile()
    Open "C:\test1.bin" For Binary Access Write As #1
    Dim d1 As Date
    d1 = "1/1/2009"
    Put #1, , d1
    Close #1
End Sub

Now let’s make a quick program in Vb.NET


Sub Main()
        Dim f As System.IO.FileStream = System.IO.File.Open("C:\test2.bin", IO.FileMode.Create, IO.FileAccess.Write)
        Dim fw As New System.IO.BinaryWriter(f)
        Dim d As Date
        d = Convert.ToDateTime("1/1/2009")
        Dim val As Long = d.ToBinary()
    End Sub


If we compare these files we will have:


So the values are obviously different. This is because VB6 Date are stores with the OLE Automation DateFormat

So let’s change the C# code for something like:


    Sub Main2()
        Dim f As System.IO.FileStream = System.IO.File.Open("C:\test3.bin", IO.FileMode.Create, IO.FileAccess.Write)
        Dim fw As New System.IO.BinaryWriter(f)
        Dim d As Date
        d = Convert.ToDateTime("1/1/2009")
    End Sub

And now when we compare the files we will have:



So to make your Date values compatible with VB6 format you must user the DateTime method .ToOADate. Now if you are calling a DLL that expects a Date value in the same format used by VB6 then you will have to do this:


        Dim d As Date
        d = Convert.ToDateTime("1/1/2009")
        Dim handle As System.Runtime.InteropServices.GCHandle = System.Runtime.InteropServices.GCHandle.Alloc(d.ToOADate(), Runtime.InteropServices.GCHandleType.Pinned)
        Dim memory_address As IntPtr = handle.AddrOfPinnedObject()
            d = DateTime.FromOADate(System.Runtime.InteropServices.Marshal.ReadInt64(memory_address))
        End Try  



Most of the time you wont have to deal with String marshalling because adding marshaling tags to your API call solves most of the problems, but if you arent that luckyly then you might do something like:

IntPtr ptrToStringVar = System.Runtime.InteropServices.Marshal.StringToHGlobalAnsi(strVar);
strVar = System.Runtime.InteropServices.Marshal.PtrToStringAnsi(ptrToStringVar);

NOTE: if you have an API that might return an string with /0 characters you must call the API with System.Runtime.InteropServices.Marshal.PtrToStringAnsi(ptrToStringVar,size), if you do that the Framework will take in consideration the size bytes at the ptrToStringVar memory address.


Double and Singles

At least between VB6 and VB.NET the double and single types follows the same format. Well, at least, that is the result of my tests.

Try it yourself, the following shows a simple test for double variables:


Private Sub SaveDoubleToFile()
    Open "C:\test1.bin" For Binary Access Write As #1
    Dim d1 As Double
    d1 = 1.123
    Put #1, , d1
    Close #1
End Sub

Sub Main()
End Sub



Module Module1

    Sub Main()
        Dim f As System.IO.FileStream = System.IO.File.Open("C:\test2.bin", IO.FileMode.Create, IO.FileAccess.Write)
        Dim fw As New System.IO.BinaryWriter(f)
        Dim d As Double
        d = 1.123
    End Sub

End Module

So you could make an api call in those cases with something like:

Dim handle As System.Runtime.InteropServices.GCHandle = System.Runtime.InteropServices.GCHandle.Alloc(d, System.Runtime.InteropServices.GCHandleType.Pinned)
Dim ptr As System.IntPtr = handle.AddrOfPinnedObject()
End Try

Change CreateObject during Migration

One of our clients wanted to change the CreateObject function migration for a function of their own. So they wanted all cases like:

Dim x As Object
Set x = CreateObject("Excel.Application")


To be migrated to something like:

Excel.Application x = (Excel.Application) Utils.MyCreateObject("Excel.Application", "");

Our migratio vb6migration tool provides a new cool feature called CustomMaps. This feature allows you to provide some simple but useful changes to the way things get migrated.

For this case follow these steps:

1. Open the Visual Basic Upgrade Companion.

2. In the Tools Menu choose:


3. Create a new CustomMaps File and an an entry like the following:



Notice the Source name is VBA.Interaction.CreateObject. To find out this name you can look in your VB6 IDE, right click on the CreateObject and select goto Definition.
and for the target name just put the implementation that you what, for example you can write a function like:
class Utils
            public static object MyCreateObject(string className,params object[] ignoreRestParams)
                return Activator.CreateInstance(Type.GetType(className));

and set the SourceName to Utils.MyCreateObject (or NameSpace.Utils.MyCreateObject to use the fully qualified name). You just need to set the New Reference Name column because we will not change the definition of the function.

.NET Calculate week number of a date

20. March 2009 06:32 by Mrojas in General  //  Tags: , , ,   //   Comments (0)
This post shows a way to calculate the number of weeks.
Remember that this calculation is culture-dependant
For example the GetWeekOfYear methods requires a criteria to determine 
how to determine the first week and which day to consider as FirstDayOfWeek for more info see here:


Supported by the .NET Compact Framework.

Indicates that the first week of the year starts on the first day of the year and ends before the following designated first day of the week. The value is 0.


Indicates that the first week of the year is the first week with four or more days before the designated first day of the week. The value is 2.


Indicates that the first week of the year begins on the first occurrence of the designated first day of the week on or after the first day of the year. The value is 1.



Sample Code

        Dim x As Date
        Dim currentCulture As System.Globalization.CultureInfo
        currentCulture = CultureInfo.CurrentCulture
        Dim weekNum = currentCulture.Calendar.GetWeekOfYear(x, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday)

Get path of ASP.NET web application that is running

If you have your ASP.NET application for example in c:\inetpub\wwwroot\WebApplication1 and you want to programmatically get that path just use something like:


string AppPath = Request.PhysicalApplicationPath;

Resizing Forms in C#

In the VB6 world it was very common to use “Resizer” OCXs that you just put on your forms and that they handle all the proportional resizing needed if you changed your form.

It was very simple and easy.

However when I started looking for something like that in .NET it was quite hard to find. So finally I got to ComponentSource and found some alternatives and I evaluated them:


Component Vendor Pricing URL
Component One Sizer For .NET Component ONE I think you have to buy the Component One Studio. That’s $800 ($1000 with more support)
and I think is one license per developer, runtime-free
.NET Forms Resize Softgroup 380$ per developer
from ComponentSource
if you buy directly from them you can get the component for 180$

Each copy is licensed on a per developer basis. A developer may use the license on multiple CPUs as long as they are not used concurrently nor used by another developer. Run-time royalty free.
Resize OCX/.NET Larcom and Young 95$-100$ per license

one license per developer, runtime-free


All of them seem to work. So it really up to your company preferences, budget and the level of support you desire. I haven't made tests like how it behaves if you have thirdparty components or activex ??? maybe I'll review that later.