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:

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.

Calling .NET from PowerBuilder

Most of our clients come from a medium-size to a big enterprise level. In these scenarios is very common to have different department using different technologies to solve their business needs.

These different technologies can be on a very homogeneous platform like .NET where you can easily interact between your VB.NET and C# assemblies, or they could be on differente technologies like ASP, Classic VB, C++, or Powerbuilder.

This post is about PowerBuilder, and in order to interact with PowerBuilder I think the easiest way is to expose your assemblies thru COM Interop.

So if there is some .NET functionality that you want to expose to PowerBuilder you just need to expose that functionality with a class in a ClassLibrary project with COM attributes.

Let’s begin with a simple program to show how to comunicate Powerbuilder with C#.

NOTE:  If you don’t have Powerbuilder you can get a trial version from: http://www.sybase.com/detail?id=1052162

1. Open Microsoft Visual Studio
2. On the File Menu, choose the New option, and in the File submenu choose Project….

Figure 1. Visual Studio File Menu. Choosing the option for a new project

1. When you choose that option a dialog window will shown with the available options for new projects. In the option for C# Projects choose “Class Library”

Figure 2. New Project dialog window

You must introduce the new project name, location and solution name. Type something like ClassLibrary1, D:\PowerBuilder, ClassLibrary1.

1. When you finish creating your project you will have a code file called Class1.cs.

2. Change that code for something like :

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

namespace SimpleClass
{
    public class Class1
    {
        public int AddTenToParameter(int param1)
        {
            return param1 + 10;
        }

        public void SayHi()
        {
            System.Windows.Forms.MessageBox.Show("Hello World!");
        }

        public String GiveMeDate()
        {
            return DateTime.Now.ToLongDateString();
        }
    }
}

This will allow to test things like parameter passing, using different return types like strings or integers. But Before you continue you must add a reference to System.Windows.Forms to be able to use the MessageBox.

Figure 3. Adding a reference

Figure 3. Reference to System.Windows.Forms

3. Right click on the solution file and select properties:

Figure 4. Option to change project properties

4. Select the Register for COM Interop  checkbox

Figure 5. Project properties window

5. Return to Class1.cs code file

6. Add an using statement after the existing using lines on Class1.cs file:

using System.Runtime.InteropServices;

7. Add the following attributes to the class:

[ComVisible(true)]

[ClassInterface(ClassInterfaceType.AutoDual)]

[ProgId("ClassLibrary1.Class1")]

Note: the ProgId is very important, because these value will be use in PB to comunicate with the this code

8. Now you must edit the AssemblyInfo.cs

Figure 6. AssemblyInfo.cs File

Now make sure to establish the COM settings in this file with statements like the following:

// Setting ComVisible to false makes the types in this assembly not visible

// to COM components. If you need to access a type in this assembly from

// COM, set the ComVisible attribute to true on that type.

[assembly: ComVisible(true)]

// The following GUID is for the ID of the typelib if this project is exposed to COM

[assembly: Guid("69efac5b-d887-40f4-a7e9-2721ac3c1598")]

The Guid is also very important, because this is used to differentiate this component and it must be unique.

To generate a new GUID you can got to the Tools Menu and choose the option Create GUID

Figure 7. Option menu to create a GUID

In the Create Guid dialog box, choose the fourth option and press Copy to put the contents on the Clipboard. Later, copy that value in the GUID attribute but remove the “{“ y “}”.

Now we are set. You only need to build the solution and the DLL. The build process with register the COM component.

If you will use the component on another computer you need to create an instalation program.

Using your program from Powerbuilder

Using your program from Powerbuilder is very easy. You just need code like the following:

Figure 8. PB Code to call a C# class thru COM

When you execute this program you will have 3 messageboxes :

• Hello World!
• 30
• Monday, March 02, 2009 (this message will change depending of the day, locale and regional settings)

Creating an instalation program

1. Right click the solution and in the context menu choose Add and then new project.

Figure 9. Context Menu to add a new project

On the dialog box for Add New projec, look for the Other Project Types section and the choose Setup Project.

Figure 10. Creating a setup project

In this dialog bos indicate the name and location of the setup project. For example Setup1 and D:\Powerbuilder\ClassLibrary1.

Later, add a project to the setup program. To do that rigth click on the setup project and select Add, and in the submenu choose Project Output.

Figure 11. Adding a project to the setup project.

A dialog box will be shown with a combo that allow you to select the proyects in the solution. Choose ClassLibrary1 and press OK.

Figure 12. Adding project output to the setup project.

When you build this instalation program two files will be produced:

Release

D:\PowerBuilder\ClassLibrary1\Setup1\Release\Setup.exe

D:\PowerBuilder\ClassLibrary1\Setup1\Release\Setup1.msi

Debug

D:\PowerBuilder\ClassLibrary1\Setup1\Debug\Setup.exe

D:\PowerBuilder\ClassLibrary1\Setup1\Debug\Setup1.msi

When you run the instalation program, this program will handle the instalation of the .NET component and the COM registration.

Debug XBAP using WinForms Host

Recently I had to deal with targeting an XBAP application that had some Windows Forms controls.

The problem is that those controls can only be used in a trusted environment. If you try to debug an XBAP with some Windows Forms Controls you will get an exception like:

Message: Cannot create instance of 'Page1' defined in assembly 'XBAPWithWinForms, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation.  Error in markup file 'Page1.xaml' Line 1 Position 7.

It took me a while to found a solution, and it was thru Scott Landford Blog that I found a way around.

In short what he recommends to do is:

Change your settings to:

Start Action->Start external program = %windir%system32\PresentationHost.exe

  In my case (and the case of most people that is: c:\windows\system32\PresentationHost.exe)

Start Options->Command line arguments = -debug "c:\projects\myproject\bin\debug\MyProject.xbap" -debugSecurityZoneUrl "http://localhost:2022"

Copy the value from the Start URL after the –debug argument

Very import for using WinForms components you must run in FULL TRUST

Here is some XBAP code using a WinForms WebBrowser. They designer does not like it a lot but it works:

XBAPWithWinforms.zip

Use C++ in C#

Migration to 64-bit: ODBC

Most people migrating their application want to move ahead and take advantage of new technologies and new operating systems.

So if you had a VB6 application and you migrated it with us to .NET we will recommend and automate the process to use ADO.NET.

Why?

You can still use ODBC but i will list some compelling reasons:

* There a very fast ADO.NET drivers available. Using ODBC implies addind an interop overhead that can affect performance.
* Some vendors do not support and/or certify the use of ODBC drivers for .NET. So in those cases if you use ODBC your are on your own.
During my consulting experience I have seen several problems using ODBC drivers ranging from just poor performance, problems with some SQL statements, stored procedures calls, database specific features or complete system inestability.
* and also problems running in 64-bit.

This last one is very concerning. If you made all the effort to migrate an application to .NET and run it on for example on a Windows 2003 64 bit server it wont be able to use your 32-bit ODBC drivers unless you go to the the Build tab, and set Platform Target to "x86".

This is very sad because your application cannot take advantage of all the 64 bit resources.

If you are lucky enough you might find a 64 bit version of your ODBC driver but I will really recommend going straigth to 64-bit and use ADO.NET. And that's exactly what we can really help you to do specially in our version 2.2 of the VBUC.

Migration of ActiveX UserDocuments to C# or .NET

This post describes an an interesting workaround that you can use to support the migration of ActiveX Documents with the Artinsoft Visual Basic Upgrade Companion which is one of the Artinsoft \ Mobilize.NET tools you can use to modernize your Visual Basic, Windows Forms and PowerBuilder applications.

Currently the Visual Basic Upgrade Companion does not allow you to process ActiveX Document directly, but there is a workaround: in general ActiveX Document are something really close to an User Control which is a element that is migrated automatically by the Visual Basic Upgrade Companion.

This post provides a link to a tool (DOWNLOAD TOOL) that can fix your VB6 projects, so the Visual Basic Upgrade Companion processes them. To run the tool:

1) Open the command prompt

2) Go to the Folder where the .vbp file is located

3) Execute a command line command like:

 FixUserDocuments Project1.vbp

This will generate a new project called Project1_modified.vbp. Migrate this new project and now UserDocuments will be supported.

VB6 allows you to create UserDocuments, which can be embedded inside an ActiveX container. The most common one is Internet Explorer. After compilation, the document is contained in a Visual Basic Document file (.VBD) and the server is contained in either an .EXE or .DLL file. During development, the project is in a .DOB file, which is a plain text file containing the definitions of the project’s controls, source code, and so on.

If an ActiveX document project contains graphical elements that cannot be stored in text format, they will be kept in a .DOX file. The .DOB and .DOX files in an ActiveX document project are parallel to the .FRM and .FRX files of a regular Visual Basic executable project. 

The trick to support ActiveX documents is that in general they are very similar to UserControls, and .NET UserControls can also be hosted in a WebBrowser. The following command line tool can be used to update your VB6 projects. It will generate a new solution where UserDocuments will be defined as UserControls.

If you have an ActiveX document like the following: 

Then after running the tool you will have an Project like the following:

So after you have upgraded the projet with the Fixing tool, open the Visual Basic Upgrade Companion  and migrate your project.

After migration you will get something like this:

To use your migrated code embedded in a Web Browser copy the generated assemblies and .pdb to the directory you will publish:

Next create an .HTM page. For example UserDocument1.htm

The contents of that page should be something like the following:

 Now all that is left is to publish the output directory.
To publish your WinForms user control follow these steps.

2. A Wizard to create a Virtual Directory will appear.

 Click Next

 Name the directory as you want. For example Project1. Click Next

 Select the location of your files. Click the Browse button to open a dialog box where you can select your files location. Click Next

 Check the read and run scripts checks and click next

 Now Click Finish

3. Properties for the Virtual Directory will look like this:

NOTE: to see this dialog right click over the virtual directory

4. Now just browse to the address lets say http:\\localhost\Project1\UserDocument1.htm

 And that should be all! :)

The colors are different because of the Host configuration however a simple CSS like:

<style>

 body {background-color: gray;}

</style>

Can make the desired change:

Notice that there will be security limitations, for example for thinks like MessageBoxes.

You can allow restricted operations by setting your site as a restricted site:

For example:

Restrictions

The constraints for this solution include:

* This solutions requires Windows operating system on the client side

* Internet Explorer 6.0 is the only browser that provides support for this type of hosting

* It requires .NET runtime to be installed on the client machine.

* It also requires Windows 2000 and IIS 5.0 or above on the server side

Due to all of the above constraints, it might be beneficial to detect the capabilities of the client machine and then deliver content that is appropriate to them. For example, since forms controls hosted in IE require the presence of the .NET runtime on the client machine, we can write code to check if the client machine has the .NET runtime installed. You can do this by checking the value of the Request.Browser.ClrVersion property. If the client machine has .NET installed, this property will return the version number; otherwise it will return 0.0.

Adding a script like:

<script>

 if ((navigator.userAgent.indexOf(".NET CLR")>-1))

 {

      //alert ("CLR available " +navigator.userAgent);

 }

  else

      alert(".NET SDK/Runtime is not available for us from within " +            "your web browser or your web browser is not supported." +            " Please check with http://msdn.microsoft.com/net/ for " +            "appropriate .NET runtime for your machine.");

</script>

Will help with that.

 References:

ActiveX Documents Definitions:

http://www.aivosto.com/visdev/vdmbvis58.html

Hosting .NET Controls in IE

http://www.15seconds.com/issue/030610.htm

Pesky VB Migration details

During migratio of a simple project, we found an interesting migration details.

The solution has a project with two Forms. Form1 and Form2. Form1 has a command button and in the Click for that command button it performs a code like UnLoad Form2.

But it could happen that Form2 has not been loaded but in VB6 it is not a problem. In .NET the code will be something like form2.Close() and it could cause problems.

A possible fix is to add some flag that indicates if the form was instanciated and the call the event.

VSS reset admin password

I had to access an old VSS database and nobody remember any password or the admin password.

The tool from this page http://not42.com/2005/06/16/visual-source-safe-admin-password-reset 

This was a lifesaver!

Scripting your applications in .NET Part 2

Just more details about scripting

Using the MS Scripting Object

The MS Scripting Object can be used in .NET applications. But it has several limitations.

The main limitation it has is that all scripted objects must be exposed thru pure COM. The scripting object is a COM component that know nothing about .NET

In general you could do something like the following to expose a component thru COM:

   [System.Runtime.InteropServices.ComVisible(true)]

    public partial class frmTestVBScript  : Form
    {
        //Rest of code
    }
 

NOTE: you can use that code to do a simple exposure of the form to COM Interop. However to provide a full exposure of a graphical component like a form or user control you should use the Interop Form ToolKit from Microsoft http://msdn.microsoft.com/en-us/vbasic/bb419144.aspx

To expose an object in COM. But most of the properties and methods in a System.Windows.Forms.Form class, use native types instead of COM types.

As you could see in the Backcolor property example:

public int MyBackColor

{

            get { return System.Drawing.ColorTranslator.ToOle(this.BackColor); }

            set { this.BackColor = System.Drawing.ColorTranslator.FromOle(value); }

}

• The problem with properties such as those is that System.Drawing.Color is not COM exposable.
• Your script will expect an object exposing COM-compatible properties.
• Another problem with that is that there might be some name collision.

Using Forms

In general to use your scripts without a lot of modification to your scripts you should do something like this:

• Your forms must mimic the interfaces exposed by VB6 forms. To do that you can use a tool like OLE2View and take a look at the interfaces in VB6.OLB
• Using those interfaces create an interface in C#
• Make your forms implement that interface.
• If your customers have forms that they expose thru com then if those forms add new functionality do this:
• Create a new interface, that extends the basic one you have and

I’m attaching an application showing how to to this.

Performing a CreateObject and Connecting to the Database

The CreateObject command can still be used. To allow compatibility the .NET components must expose the same ProgIds that the used.

ADODB can still be used, and probably RDO and ADO (these last two I haven’t tried a lot)

So I tried a simple script like the following to illustrate this:

Sub ConnectToDB
'declare the variable that will hold new connection object

Dim Connection 
'create an ADO connection object

Set Connection=CreateObject("ADODB.Connection")
'declare the variable that will hold the connection string

Dim ConnectionString 
'define connection string, specify database driver and location of the database 

ConnectionString = "Driver={SQL Server};Server=MROJAS\SQLEXPRESS;Database=database1;TrustedConnection=YES"

'open the connection to the database
Connection.Open ConnectionString 
MsgBox "Success Connect. Now lets try to get data"
'declare the variable that will hold our new object

Dim Recordset   
'create an ADO recordset object
Set Recordset=CreateObject("ADODB.Recordset") 
'declare the variable that will hold the SQL statement

Dim SQL    
SQL="SELECT * FROM Employees" 
'Open the recordset object executing the SQL statement and return records 
Recordset.Open SQL, Connection
'first of all determine whether there are any records 
If Recordset.EOF Then 
    MsgBox "No records returned."
Else 
'if there are records then loop through the fields 

Do While NOT Recordset.Eof   
 MsgBox Recordset("EmployeeName") & " -- " & Recordset("Salary")
  Recordset.MoveNext     
Loop

End If

MsgBox "This is the END!"

End Sub

I tested this code with the sample application I’m attaching. Just paste the code, press Add Code, then type ConnectToDB and executeStatement

I’m attaching an application showing how to do this. Look at extended form. Your users will have to make their forms extend the VBForm interface to expose their methods.

Using Events

Event handling has some issues.

All events have to be renamed (at least this is my current experience, I have to investigate further, but the .NET support for COM Events does a binding with the class names I think there’s a workaround for this but I still have not the time to test it).

In general you must create an interface with all events, rename then (in my sample I just renamed them to <Event>2) and then you can use this events.

You must also add handlers for .NET events to raise the COM events.

     #region "Events"

        public delegate void Click2EventHandler();
        public delegate void DblClick2EventHandler();
        public delegate void GotFocus2EventHandler();

        public event Click2EventHandler    Click2;
        public event DblClick2EventHandler DblClick2;
        public event GotFocus2EventHandler GotFocus2;

        public void HookEvents()
        {
            this.Click += new EventHandler(SimpleForm_Click);
            this.DoubleClick += new EventHandler(SimpleForm_DoubleClick);
            this.GotFocus += new EventHandler(SimpleForm_GotFocus);
        }

        void SimpleForm_Click(object sender, EventArgs e)
        {
            if (this.Click2 != null)
            {
                try
                {
                    Click2();
                }
                catch { }
            }
        }

        void SimpleForm_DoubleClick(object sender, EventArgs e)
        {
            if (this.DblClick2 != null)
            {
                try
                {
                    DblClick2();
                }
                catch { }
            }

        }


        void SimpleForm_GotFocus(object sender, EventArgs e)
        {
            if (this.GotFocus2 != null)
            {
                try
                {
                    GotFocus2();
                }
                catch { }
            }
        }



        #endregion

Sadly there isn’t currently a nice solution for scripting in .NET.  Some people have done some work to implement something like VBScript in .NET (including myself as a personal project but not mature enough I would like your feedback there to know if you will be interesting in a managed version of VBScript)  but currently the most mature solution I have seen is Script.NET. This implementation is a true interpreter. http://www.codeplex.com/scriptdotnet Also microsoft is working in a DLR (Dynamic Languages Runtime, this is the runtime that I’m using for my pet project of VBScript)

The problem with some of the other solutions is that they allow you to use a .NET language like CSharp or VB.NET or Jscript.NET and compile it. But the problem with that is that this process generates a new assembly that is then loaded in the running application domain of the .NET Virtual machine. Once an assembly is loaded it cannot be unloaded. So if you compile and load a lot of script you will consume your memory. There are some solutions for this memory consumption issues but they require other changes to your code.

Using other alternatives (unless you used a .NET implementation of VBScript which currently there isn’t a mature one) will require updating all your user scripts. Most of the new scripts are variants of the Javascript language.

No. There aren’t a lot of tools for this task. But you can use http://slingfive.com/pages/code/scriptConverter/

ADODB RecordSet Save in C# ASP.NET

I saw this with Francisco and this is one possible solution: