Microsoft has put my 'Dual List' .NET Magazine article online!
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Microsoft has put my Visueel programmeren met .NET: Dual List Control article online. It is published in the .NET Magazine #8 and it is free for Dutch developers. |
WaitCursor
For a long time I thought that I only had to set the Cursor.Current to a WaitCursor before a long running operation, the .NET runtime would reset it back to the Default cursor. Turns out that this is only true when the mouse is moved. Bummer.
// mouse is moved and the application is idle!
Cursor.Current = Cursors.WaitCursor;
The solution for this problem is very easy. I created a helper class called WaitCursor which set the Cursor.Current and restores it to the original value when it it disposed.
private Cursor _prev;
public WaitCursor() {
_prev = Cursor.Current;
Cursor.Current = Cursors.WaitCursor;
}
public void Dispose() {
Cursor.Current = _prev;
}
}
I create the instance of the WairCursor class inside a using statement. This will automatically call the Dispose() method when it goes out of scope.
// long running operation, for example:
System.Threading.Thread.Sleep(1000);
}
Afterwards I did some searching around on the web. Turns out I'm not the first to come up with this solution. Charlie Poole already posted it a few years ago. Another bummer.
Micro-ISV
Microsoft has invented a new name Micro-ISV, which are software companies that are comprised of only one person. So, I'm a Micro-ISV. Planning to launch my product this year. I hope to succeed.
Dispose Modal WinForm Dialogs
There is a difference in disposing Modal and Non-Modal forms. In a training I gave last week I noticed that even experienced developers didn't know that Modal Dialogs don't dispose automatically, Non-Modal do.
new TestForm().Show();
}
private void buttonShowModalDialog(object sender, System.EventArgs e) {
new Form2().ShowDialog();
}
The solution to this problem is very simple by creating the Form instance within a using block. This will dispose the Form when it is closed.
using (TestForm f = new TestForm()) {
f.ShowDialog();
}
}
An alternative solution uses a try/finnaly. Personally I prefer the previous, it is easier to read and write.
TestForm f = null;
try {
f = new TestForm();
f.ShowDialog();
} finally {
if (f != null) {
f.Dispose();
}
}
}
The following solution isn't correct. You might think it is, but it isn't. The Dispose will not be executed when an Exception is thrown from within the ShowDialog().
TestForm f = new TestForm();
f.ShowDialog();
f.Dispose();
}
Best CV ever!
C# HandleWhiteSpace Add-In
Download WhiteSpace.zip
Introduction
The C# code editor in Visual Studio.NET 2003 does not handle whitespaces automatically like the VB.NET code editor does. This Add-In solves this problem by adding the 'Handle WhiteSpace' menu option to the Visual Studio.NET 2003 Tools menu. This option formats the C# code of the active code editor. This includes:
- Space before: method declaration parentheses, method call parentheses, statement parentheses, braces and brackets
- Space after: comma and semicolon
- Space around: operators
- Double space
Example
Screen shot: Handle WhiteSpace menu option
After you have selected the menu option the C# source code is formatted with correct whitespaces.
Screen shot: Reformatted code
Conclusion
Writing clean C# code has become easier with this Add-In. I hope you enjoy using it.
I thank Heindirk de Laat for providing me the code for the most difficult part of the program. I only added some extra regular expressions and transformed it into an Add-In.
Any suggestions and feedback for improving this Add-In is most welcome. Send your suggestions and feedback to Fons.Sonnemans@reflectionit.nl
DualList Drag & Drop Component
Introduction
I have written an article two years ago with the title 'WinForm DualList Component'. In this article I mentioned the desire to extend the DualList component with Drag & Drop support. Finally it's done. Not by extending the original DualList component but by creating an new DualListDragDrop component (reason: cohesion).
Programming Drag & Drop (D&D) between listboxes is quite difficult. It requires at least 60 lines of code for every two listboxes. Therefore not many application support D&D. This component eliminates need of writing the code. You only have to set properties on it. Making it easy to support D&D in your applications.
DualListDragDrop Component
The DualListDragDrop component is a component which can be dropped in the 'component tray' of a windows Form. You therefore first have to add it to the Toolbox of Visual Studio.NET. This can easily be done by dragging ReflectionITWinFormComponents.dll assembly from an normal Windows Explorer and dropping it on the Toolbox. All controls and components from the assembly will be added to the Toolbox. You can create an separate Tab for it if you want.
For each D&D direction you must add DualListDragDrop component to you Form. In this example three. For each component you have to set the '(Name)', 'ListBoxFrom' and 'ListBoxTo' properties.
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You can use the DualListDragDrop component to reorder the position of the items in a ListBox by selecting the same 'From' and 'To' ListBox.
Action property
You can choose from three values for the Action property: Move, Copy and MoveAndCopy. The MoveAndCopy will normally move an item. You can copy the item by pressing the Ctrlkey while initiating the D&D operation.DropIndicator property
The DropIndicator can be set to 'True' which means you will get a red dotted line indicating where the item will be placed when you drop the item. It supports scrolling the listbox up and down when you move your mouse over the first or last visible item. The item will be added to the bottom of the list when the property is set to 'False'. The color of the line can be selected using the IndicatorColor property.Conclusion
The DualList and DualListDragDrop components are easy solutions for difficult features. It takes care of all logic needed to move and or copy items from one listbox to another. Use them in your own applications, they are free.
Hopefully this article will encourage more people to make use of the component architecture in their own applications.
Any suggestions and feedback for improving this article is most welcome. Send your suggestions and feedback to Fons.Sonnemans@reflectionit.nl
License Information
The ReflectionITWinFormComponents assembly is free for use in commercial or private applications. However, you may only redistribute this in its compiled form (modified or unmodified), you may not redistribute the source or modified source. When using it, please include the line "ReflectionITWinFormComponents - Copyright Reflection IT - http://www.reflectionit.nl/" reference in either the about or in the documentation. This will help me out and allow me to continue to provide you with free controls.
ToolboxBitmap workaround
I have found a solution for a problem which I had for a long time. I was unable to set the ToolboxBitmap attribute for a component using the (type, string) constructor. I found the solution for this problem (using an internal ResFinder class) on www.bobpowell.net. This site has also some other Windows Forms Tips and Tricks. Great!
New layout www.reflectionit.nl
I have changed the layout of my website this weekend. A friend of my helped me with the design, thanks Loek
I'm not really finished. I still have to translate some pages to Dutch. I also want to add 'comments' to the Blog. Hope to do this soon.
Visual C# 2005 Express Edition Beta is great
I'm testing Visual C# 2005 Express Edition Beta and I really like it. It has all of the features which I need to build Windows Forms applications. The Editor has also all new IntelliSense, Refactoring and Code Snippets features. They work great and really can boost productivity.
I have tested it on a PC with only 256Mb of ram. This is for the beta not enough. You need at least 512Mb.
I'm using the Online MSDN Help, it works OK. The looks are good but I find it difficult to get to the 'overview' of a class.
For professional development I would advise to use Visual Studio. For hobby work use the Express versions.
All postings/content on this blog are provided "AS IS" with no warranties, and confer no rights. All entries in this blog are my opinion and don't necessarily reflect the opinion of my employer or sponsors. The content on this site is licensed under a Creative Commons Attribution By license.