Don’t you hate it when you get some source code and the tab spacing is different than yours? I know I do. You could go line by line and press backspace, which is not the smartest way to do it (I was guilty of this).
Here’s the much simpler way to get the tabs aligned:
So I tried to make a folder within TFS called “R&D” and it let me. No surprises…yet. After moving a project into this folder, I ran the project to make sure all paths/references were still intact. The project ran fine so things seemed okay.
It wasn’t until I tried opening a form up in Designer view that I got a weird error:
How is it that the project can build and run fine, but I’m seeing this? XML? I don’t have anything related to XML in the form code, so what gives? After doing some searching on the internet, it seems that the “&” character anywhere in the path causes this issue. Since my project was in the “R&D” folder, I was having this issue. I renamed the folder and the problem went away…
As I learn WPF I’m running into quite a few roadblocks, but I’m enjoying the fact that it’s a challenge and something new. One of the things I’m trying to get used to is Data Binding to the WPF UI. I’m also trying to learn WPF the MVVM way. There are a lot of examples on how to do this on the web so I’ll just get to what got me stuck for a bit on ComboBox items binding. Here’s some of my UI XAML and my code behind:
<DockPanel Margin="0" Height="42" Name="TopDockPanel" Width="auto" DockPanel.Dock="Top" LastChildFill="true">
<Grid Height="auto" Name="Grid1" Width="266" DockPanel.Dock="Left">
<Label Margin="7,7,0,9" HorizontalAlignment="Left" Width="71">Combo1:</Label>
<ComboBox ItemsSource="{Binding ComboList1}" Margin="84,9,22,13" SelectionChanged="Combo1_SelectionChanged" />
</Grid>
<Grid Height="auto" Name="Grid2" Width="281">
<Label HorizontalAlignment="Left" Margin="6,7,0,9" Width="89">Combo2:</Label>
<ComboBox ItemsSource="{Binding ComboList2}" Margin="101,9,20,13" IsEditable="False" />
</Grid>
<Grid Height="auto" Name="Grid3" Width="auto" />
</DockPanel>
Class SomeClass
Private _SomeClassVM As SomeClassViewModel = Nothing
Sub New()
' This call is required by the Windows Form Designer.
InitializeComponent()
' Add any initialization after the InitializeComponent() call.
_SomeClassVM = New SomeClassViewModel
Me.DataContext = _SomeClassVM
End SubPrivate Sub Combo1_SelectionChanged(ByVal sender As System.Object, ByVal e As System.Windows.Controls.SelectionChangedEventArgs)
_SomeClassVM.Combo1Changed(sender)
End Sub
End Class
Nothing complicated, a simple MVVMish implementation (ish because there’s event handler code in the code behind file, I’ll be refactoring this as I go on). My View Model implements the INotifyPropertyChanged Interface so that the UI can be notified of any property changes and update any data bindings as needed. My View Model also exposes a couple of Public Properties: ComboList1 and ComboList2 which are List (Of String) objects:
Public Class SomeClassViewModel
Implements INotifyPropertyChanged
Private _ComboList1 As List(Of String)
Private _ComboList2 As List(Of String)Public ReadOnly Property ComboList1() As List(Of String)
Get
Return _ComboList1
End Get
End Property
Public ReadOnly Property ComboList2() As List(Of String)
Get
Return _ComboList2
End Get
End Property
Sub New()
_ComboList1 = New List(Of String)
For Each item As String In ItemsList 'this is just a list of strings from anywhere
_ComboList1.Add(item)
Next
OnPropertyChanged("SQLServerList")
_ComboList2 = New List(Of String)
End Sub
Public Sub Combo1Changed(ByVal sender As System.Object)
_ComboList2.Clear()
For Each item As String In SomeOtherList 'this is just list of string from another place
_ComboList2.Add(sqlDatabase)
Next
OnPropertyChanged("ComboList2")
End Sub
Public Event PropertyChanged(ByVal sender As Object, ByVal e As System.ComponentModel.PropertyChangedEventArgs) Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
Private Sub OnPropertyChanged(ByVal propertyName As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
End Sub
End Class
Now, I thought that clearing and adding items to my ComboList2 object would suffice in propagating change notifications up to the UI…WRONG. It seems there’s more to it than just clearing/adding to the list and raising the PropertyChanged event. This implementation only notified the UI that ComboList2 changed once at the first time I changed ComboBox1’s selected item instead of each time. What gives?
After some fiddling I found that I couldn’t use the current _ComboList2 object reference. I had to actually set the _ComboList2 object to a new List for the UI to update:
Public Sub Combo1Changed(ByVal sender As System.Object)
Dim NewList As New List(Of String)
For Each item As String In SomeOtherList 'this is just list of string from another place
NewList.Add(item)
Next
_ComboList2 = NewList
OnPropertyChanged("ComboList2")
End Sub
There’s a more elegant way to solve the issue I had, which is to use an ObservableCollection instead of List (Of String) objects:
Public Class SomeClassModel
Private _ComboList1 As ObservableCollection(Of String) = Nothing
Private _ComboList2 As ObservableCollection(Of String) = Nothing
Public ReadOnly Property ComboList1() As ObservableCollection(Of String)
Get
Return _ComboList1
End Get
End Property
Public ReadOnly Property ComboList2() As ObservableCollection(Of String)
Get
Return _ComboList2
End Get
End Property
Sub New()
_ComboList1 = New ObservableCollection(Of String)
For Each item As String In ItemsList 'this is just a list of strings from anywhere
_ComboList1.Add(item)
Next
_ComboList2 = New ObservableCollection(Of String)
End Sub
Public Sub Combo1Changed(ByVal sender As System.Object)
_ComboList2.Clear
For Each item As String In SomeOtherList 'this is just list of string from another place
_ComboList2.Add(item)
Next
End Sub
End Class
You’ll notice a couple of things. The first being that the View Model no longer needs INotifyPropertyChanged. This is because ObservableCollection implements INotifyPropertyChanged (and INotifyCollectionChanged). You’ll also notice that I was able to just clear/add to _ComboList2 without having to raise any events. The UI updated as expected and I suspect it’s because when clearing or adding items to the ObservableCollection, properties such as count raise the PropertyChanged event properly.
Have you ever had a class library that uses an Interface? How about two or more libraries that need to use the same Interface? For instance, ClassLibrary1 and ClassLibrary2 need to implement ISomeInterface below:
Instead of copying ISomeInterface.vb to both ClassLibrary projects or adding a project reference, you can add a link to ISomeInterface.vb and have access to ISomeInterface:
Now you’ll notice that ISomeInterface.vb is part of ClassLibrary1 as a linked file:
Now we can implement ISomeInterface in ClassLibrary1:
The benefit of adding the Interface file as a link is that you can maintain the Interface in one location. You don’t have to worry about having to copy new versions if you decide to change your contract.
This post by Greg inspired me to post to my blog about some of the free software utilities and applications that I use at home. Although some of the things I list may not be the absolute best, it really is hard to beat free. Plus a lot of times the term “best” is used subjectively and this includes software.
7-Zip is a compression utility used for packing and unpacking various file formats. Think of it as an open source WinZip. Below is the main feature list from the 7-Zip website:
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Every Windows user needs and anti-virus application. The one I use is Avast because it seems to be the least intrusive. I haven’t had a single problem since I began using Avast over a year ago. Here are some of the features:
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Ever have issues with your OS or feel that your registry has become a bit dirty? CCleaner may help you find the issues. I use it regularly to clean out unnecessary temporary and log files. I also use it to check for any registry issues:
“CCleaner is a freeware PC optimization tool. It combines a system cleaner that removes unused and temporary files from your system and also a fully featured registry cleaner! CCleaner allows Windows to run faster, more efficiently and gives you more hard disk space. The best part is that it's Small, Fast and Free!”
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CDBurnerXP is one of the best disc burning applications I’ve ever used, free or otherwise. It handles everything I throw at it without any issues:
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Hate scratched audio CDs? I know I do. I use CDex to rip from the original disc so that I don’t have to worry about scratching up the original:
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Into news feeds? Then you should be using FeedDemon. It will sync to your Google Reader account:
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Is Photoshop a bit too expensive for you? Try Paint.NET. I use it for editing images, creating icons, and a myriad of other minor image tasks. A true power user can do much more than I can with it:
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Do you chat with friends that use different IM networks? Trillian is a great application that supports various IM networks. MSN, AIM, Yahoo, ICQ, and IRC are supported.
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How am I writing this blog post? Windows Live Writer of course. Greg turned me on to this application and it makes blog posting must simpler:
“Writer makes it easy to share your photos and videos on almost any blog service—Windows Live, Wordpress, Blogger, LiveJournal, TypePad, and many more.”
I noticed that the Canvas class doesn’t use the Cartesian coordinate system for mapping points. For instance, here’s a list of points: 0, 0; 15, 5; 25, 18. Here’s how these points look when drawn to a Canvas:
The above image is fine if that’s what you want to do with the points, but that isn’t the result I wanted. I had to add a ScaleTransform to the Canvas for it to look the way I wanted. This can be done in XAML:
<Canvas Name="MainCanvas" Background="AliceBlue" Width="400" Height="200" > <Canvas.RenderTransform> <ScaleTransform CenterX="200" CenterY="100" ScaleX="1" ScaleY="-1" /> </Canvas.RenderTransform> </Canvas>
or programmatically (VB.NET here):
Dim YScale As New ScaleTransform YScale.ScaleX = 1 YScale.ScaleY = -1 YScale.CenterX = MainCanvas.Width / 2 YScale.CenterY = MainCanvas.Height / 2 MainCanvas.RenderTransform = YScale
You’ll notice the CenterX and CenterY properties are set to the middle of the Canvas. You can think of this as your pivot point when flipping the Canvas (The CenterX isn’t really needed here since we’re just flipping on the Y axis).The end result is what I was expecting:
So I was trying to write unit tests today and I ran into quite a weird issue. My test failed on a simple constructor test. When I looked at the error message I noticed something odd:
The referenced assembly version in the picture is x.x.x.91, but the current version it should be is a later version. What gives? I tried creating a new unit test project because I thought maybe our unit test project got messed up somehow, but the same error message kept on happening. Another frustrating issue was that when I ran the unit test in debug mode, it passed correctly.
After some searching on the web I ran into this page, which led me to check the project’s code coverage instrumentation section. Sure enough, the project was pointing to an assembly that no longer existed. The red one was the non-existent assembly, the green one is the correct one.
My guess as to why this happened was because initially, the solution was setup to build against Any CPU and this was changed to x86 somewhere along the way. The LocalTestRun.testrunconfig probably never got updated. After pointing to the correct assembly, the test passes and no odd version issues exist.
Incidentally, I asked Greg if his laptop ran into some slowness lately because my hard drive would thrash and adding unit tests literally took me longer than 5 minutes via right-click. Correcting the instrumented assembly corrected this issue as well. One would think that Visual Studio would let the user know that something was up :)
Have you ever tried to open a comma delimited .csv file in MS Excel and gotten these dialogs?
There might actually be nothing wrong with your file. If the first item happens to be ID (case sensitive), you will get this dialog in Excel (I’ve had this happen to me in 2003 and 2007). If you don’t want this dialog to keep coming up, you’ll have to rename the first item or just change the casing of ID to id, Id, or iD.
