Rick van den Bosch - Blog : Development

Error: The Path 'path' is already mapped in workspace 'workspace'

Rick van den Bosch — Tue, 02 Apr 2013 07:35:00 GMT

Just a quick little post today: I got the error "The Path 'path' is already mapped in workspace 'workspace'" when I connected to a new Team Foundation Server and tried to map my workspace today. I had connected to a Team Foundation Services project a while back to get some shared code, but I already removed the workspace and the server binding. Even though Visual Studio didn't see any other bindings, mapping my workspace to the same folder the previous TFS binding was mapped to served me this error.

The quick solution: manually edit (or remove if you don't have any other bindings) the file VersionControl.config, which can be found under %AppData%\Local\Microsoft\Team Foundation\4.0\Cache

Hope this helps.

Visual Studio 2012 crashes when opening an ASP.NET MVC project with a cshtml open

Rick van den Bosch — Fri, 15 Mar 2013 10:54:59 GMT

A rather long title for this post, but that’s exactly what happened: when I opened an ASP.NET MVC 4 project with a cshtml view open, Visual Studio would crash with the error messages seen on the right. This would only occur if the first project I opened had a cshtml file open. When I opened another (type of) project first and then opened a project with a cshtml file open, the problem did not occur. Debugging Visual Studio with a new instance of Visual Studio (Inception anyone?) made things a bit clearer. (Part of) the exception information:

Source
WebEssentials2012

Message
Could not load type 'Microsoft.Less.Core.LessMixinDeclaration' from assembly 'Microsoft.VisualStudio.Web.Extensions, Version=11.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.

After searching around a bit, I found this blog post by Mads Kristensen: Web Tools 2012.2 and Web Essentials. This post talks about Web Tools 2012.2 and Web Essentials 2.5, and how an error can occur if you install Web Tools 2012.2 and don’t upgrade to Web Essentials 2.5. However, I do have Web Essentials 2.5.1 installed so this issue shouldn’t be the same as mine.

Although my situation didn’t match the one on Mads’s blog, I decided to install Web Tools 2012.2 just to see what the result would be. As it turned out, installing the Web Tools 2012.2 did solve the problem. Here’s why I think this solved it:

I had an older version of WebEssentials installed, which included specific functionality. This functionality was moved to Web Tools, and out of the new version of Web Essentials. When I updated to the new version of Web Essentials (without having Web Tools installed!), the functionality was no longer available in Web Essentials giving me the ‘Could not load type’ exception.
I’m not sure why the exception did not occur when I opened a different project first or if this is the exact reason of the exception occurring. I’ll contact Mads to share my findings, he might be able to reproduce this.

Hope this helps

How to add Next and Previous buttons to Twitter Bootstrap tabs

Rick van den Bosch — Wed, 16 Jan 2013 09:02:56 GMT

Just a quickie today: when working with Twitter Bootstrap tabs, like I am in my ASP.NET MVC 4 project, you might want to add Next and Previous buttons on the tabs to create something of a Wizard. Here’sa step by step overview of how I did this:

Add an ID to all the ListItem elements that are used for the tab navigation. For instance:

<ul class="nav nav-tabs" id="myTab">
    <li><a href="#example" data-toggle="tab" id="xmpl">Example</a></li>
    ...
</ul>

Add a button you would like to use to activate the Example tab

In the onclick, call the ShowTab JavaScript function with the id of the ListItem for the Example tab (which is ‘xmpl’ in this example)

The ShowTab function is simple:

function ShowTab(tabname) { 
    $('#' + tabname).tab('show'); 
}

Hope this helps

How To: Call a generic method with a runtime type

Rick van den Bosch — Sun, 02 Dec 2012 10:17:00 GMT

Problem:
Developing a generic class that maps datasets, datatables and datarows from a legacy system to my domain model, I ran into an issue. I wanted to call a generic method with a runtime type. Lets say the method looked like this: public string DoSomething<T>(string param). Because I use reflection to iterate properties on a type, the type of the properties was dynamic and only known at runtime. I wanted to do something like this:

DoSomething<propertyInfo.PropertyType>("bloggingabout");

This however resulted in an error message. The tooltip on the red colored propertyInfo read "Cannot resolve symbol 'propertyInfo'", while the build error stated "The type or namespace name 'propertyInfo' could not be found (are you missing a using directive or an assembly reference?)". This is expected behavior, because "The type argument [...] can be any type recognized by the compiler." So that says compiler. So the type is parsed (and should be known) at compile time.

Solution:
The solution is found in reflection. Taken from the MSDN article for the MethodInfo.MakeGenericMethod Mehod:
The MakeGenericMethod method allows you to write code that assigns specific types to the type parameters of a generic method definition, thus creating a MethodInfo object that represents a particular constructed method. If the ContainsGenericParameters property of this MethodInfo object returns true, you can use it to invoke the method or to create a delegate to invoke the method.

In our example, this would look something like this:

instance.GetType()
       .GetMethod("DoSomething")
       .MakeGenericMethod(propertyInfo.PropertyType)
       .Invoke(mapper, new object[] { "bloggingabout" });

More information:
Generic Type Parameters (C# Programming Guide)
MethodInfo.MakeGenericMethod Method

How To: Create an ActionLink with a Twitter Bootstrap icon in MVC4

Rick van den Bosch — Wed, 07 Nov 2012 18:16:00 GMT

Twitter Bootstrap is a... "Sleek, intuitive, and powerful front-end framework for faster and easier web development." One of the nice things in Bootstrap is you can use icons from Glyphicons. To use these, you can simply use this markup <i class="icon-fire"></i> get a nice fire icon ( ).
Translating this into an ActionLink styled as a button in an MVC4 application would look something like the following:

@Html.ActionLink("<i class=\"icon-fire\"></i> Invent fire", "fire", new { @class = "btn" })

Unfortunately, this renders as follows:

The reason this is not rendered correctly is because Html.ActionLink HtmlEncodes the text you pass in the actionLink parameter. You can check this by opening the System.Web.Mvc assembly in your disassembler of choice, and having a look at the GenerateLinkInternal method on the HtmlHelper class. It HtmlEncodes the linkText, and doesn't have any option to have it not do that. To solve this, I wrote an extension method called NoEncodeActionLink, looking like this:

public static IHtmlString NoEncodeActionLink(this HtmlHelper htmlHelper, string linkText, string action, object htmlAttributes) 

{ 

    TagBuilder builder; 

    UrlHelper urlHelper; 

    urlHelper = new UrlHelper(htmlHelper.ViewContext.RequestContext); 

    builder = new TagBuilder("a"); 

    builder.InnerHtml = linkText; 

    builder.Attributes["href"] = urlHelper.Action(action); 

    builder.MergeAttributes(new RouteValueDictionary(htmlAttributes)); 


    return MvcHtmlString.Create(builder.ToString());

}

Calling the new overload (don't forget to add a using statement to the namespace holding the extension method), the linkText parameter is not HtmlEncoded, which means the ActionLink now renders fine, including the icon (and the button style):

Hope this helps.

TIP: “Paste XML as Classes” in Visual Studio 2012

Rick van den Bosch — Wed, 24 Oct 2012 05:02:00 GMT

In the past, when you had some XML document that you wanted to translate into classes we had to create / generate a schema based on the XML file. Next, we had to generate a class based on the schema with an external tool. Not all too user friendly and somewhat time consuming.

In Visual Studio 2012 you copy the XML you want to create a class/classes for, place the cursor in a class file on the location you want the code to be added and select the following menu items: Edit – Paste Special – Paste XML as Classes. And you’re done! Just like that…

If you want to try real quick, there’s a sample XML file (books.xml) available here.

EDIT
The feature is .NET Framework 4.5 specific. Taken from this MSDN article 'Generating Data Type Classes from XML':
".NET Framework 4.5 includes a new feature to generate data type classes from XML."

Documents.Open returns null, running Word automation under ASP.NET on x64

Rick van den Bosch — Thu, 02 Feb 2012 04:53:00 GMT

When building an ASPapplication that generates Word documents, it was working fine on the local machine. A windows XP installation with Office 2007. When we deployed it to windows 2008 (64 bit) and Word 2007 we saw that Documents.Open returned null. Other than this, there are no exceptions.

The code that returned the error (simplified):

Application app = new Application();
Document doc = app.Documents.Open(ref name);

As it turns out, a 64 bit system stores temporary files in "C:\Windows\SysWOW64\config\systemprofile\Desktop" folder.

The solution: create a new directory called "Desktop" inside "C:\Windows\SysWOW64\config\systemprofile\"

Hope this helps.

Unhandled exception installing SQL Server 2008 R2 on a Windows XP / Windows 7 machine

Rick van den Bosch — Fri, 27 Jan 2012 04:46:00 GMT

When installing SQL Server 2008 R2 on a Windows XP (or, according to the comments, Windows 7) development machine that has been around for quite some time, I got an error stating an unhandled exception occured in the application (see image). The error showed up directly upon startup and read:

An error occurred creating the configuration section handler for userSettings/Microsoft.SqlServer.Configuration.LandingPage.Properties.Settings: Could not load file or assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies.

Repairing the .NET 4.0 framework didn't solve the issue. Neither did removing all SQL stuff through 'Add or Remove Programs'. Looking into the error a bit further...

The system cannot find the file specified. (C:\Documents and Settings\_USERNAME_\Local Settings\Application Data\Microsoft_Corporation\LandingPage.exe_StrongName_ryspccglaxmt4nhllj5z3thycltsvyyx\10.0.0.0\user.config line 5) ---> System.IO.FileNotFoundException: Could not load file or assembly 'System, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' or one of its dependencies. The system cannot find the file specified.

So the problem probably wasn't that System.dll couldn't be found, but some user.config file for the landingpage executable. The solution is as simple as it is radical: remove the entire (temporary) folder 'C:\Documents and Settings\_USERNAME_\Local Settings\Application Data\Microsoft_Corporation' (where USERNAME_ is, of course, the current username). After this the setup should start up without any problems.

The Visual Studio 2010 Test Client for WCF services

Rick van den Bosch — Wed, 01 Jun 2011 05:21:00 GMT

When writing WCF services, most of us find ourselves writing quick test applications. To give you more time to do what a developer should be doing (adding business value to the project) the Visual Studio team added a WCF test client that can help you reach goals faster.

This is not a very difficult application, but it does the trick and is more than sufficient for simple testing. The WCF Test Client can be found at this location (without the ‘ (x86)’ for x86 machines): C:\Program Files (x86)\Microsoft Visual Studio 10.0\Common7\IDE.

Taken from the help:

Windows Communication Foundation (WCF) Test Client (WcfTestClient.exe) is a GUI tool that allows users to input test parameters, submit that input to the service, and view the response that the service sends back. It provides a seamless service testing experience when combined with WCF Service Host.

WCF Test Client screenshots:

Updated: Thanks to Marco for pointing out my typo...!

HowTo: Save a file from Silverlight using the SaveFileDialog

Rick van den Bosch — Thu, 20 Jan 2011 17:23:57 GMT

Saving a file from Silverlight using the SaveFileDialog, added in Silverlight 3, is easy. If you’re used to desktop development however, you might find yourself getting a SecurityException with the message ‘File operation not permitted. Access to path 'xxx' is denied.’. Here’s why:

In desktop development, you’re used to getting a filename from a SaveFileDialog. Next, you start doing whatever you need to be doing to the file, based on the filename. This would look something like this:

SaveFileDialog saveFileDialog = new SaveFileDialog();

if (saveFileDialog.ShowDialog() == true)
{
    StreamWriter streamWriter = new StreamWriter(saveFileDialog.SafeFileName);
    streamWriter.Write("Follow me on twitter: @rickvdbosch");
    streamWriter.Flush();
    streamWriter.Close();
}

This results in the SecurityException. First time I saw the property, I genuinely thought it said SaveFileName. But, as you can see, it says SafeFileName. It is named safe, because the returned file name has all file path information removed for security purposes.

In Silverlight, if you want the above functionality, it should look something like this:

SaveFileDialog saveFileDialog = new SaveFileDialog();

if (saveFileDialog.ShowDialog() == true)
{
    StreamWriter streamWriter = new StreamWriter(saveFileDialog.OpenFile());
    streamWriter.WriteLine("Follow me on twitter: @rickvdbosch");
    streamWriter.Flush();
    streamWriter.Close();
}

The OpenFile method opens the file specified by the SafeFileName returning a Stream, giving you the opportunity to save whatever you want to save over there.

Hope this helps.

On a side note: the ‘== true’ part in the if condition is needed in this case. Because the ShowDialog method returns a nullable boolean it is not enough to use saveFileDiaolog.ShowDialog() in the condition. Just so you know… :)

HowTo: open all files from the Find Results window

Rick van den Bosch — Mon, 17 Jan 2011 05:49:00 GMT

Here’s a quick Visual Studio tip for you…

I frequently search for a specific text in my solution because I need to do something in all places where that text occurs. Today I found out how you can open all the files that are mentioned in the Find Results window.

Search for the text you’re looking for. In my case this is ITest*.
Open up the Search Results window and select all the records where the text was found. You can do this by dragging your mouse cursor over the text or clicking the text of the first search result, holding SHIFT and clicking the text of the last.

Right click anywhere on the selected text and choose ‘Go to location’. If you click anywhere other than on selected text, you will lose the selection and you’ll probably get just one file opened. When all files are opened you will keep the ‘Go To Next Location F8’ and ‘Go To Previous Location SHIFT + F8’ functionality. That might be a nice one to loop through all the locations where your text was found. Especially when it was found more than once in one file.

Hope this helps.

* The usefulness of searching for this interface is arbitrary due to functionality as ‘Find all references’ and so on. Luckily I’m only using it for this example. So lets not focus on that but on the tip this post is about ;)

HowTo: have Visual Studio open XAML documents in code view

Rick van den Bosch — Tue, 04 Jan 2011 09:25:18 GMT

Just a small post to start the new year... and let it be a good one!

When opening a XAML document in Visual Studio, it opens in split view by default. This might become annoying when you have a large XAML document, because all the content needs to be rendered before you can get some work done.

Here’s how you can have Visual Studio open XAML documents in code view:

Go to Tools, Options
Under Text Editor open the XAML section and select Miscellaneous
Under Default View check the Always open documents in full XAML view box (see image below)
Click OK to apply and you’re all done!

Hope this helps.

Little-heard-of ASP.NET feature: app_offline.htm

Rick van den Bosch — Fri, 08 Oct 2010 07:43:00 GMT

Although the feature has been around since ASP.NET 2.0, I still meet people that don't know and/or use app_offline.htm. Do you know (and use) the feature...?

When working on an ASP.NET web application, you should notify your visitors in a decent way that your application is down. There's a nice default feature available for these purposes since ASP.NET 2.0. Somehow, however, this feature is not very well known and rarely used. The "App_Offline.htm" feature in ASP.NET 2.0 provides an easy way to bring down an ASP.NET application while you make changes to it. This feature kicks in as soon as you place a file called app_offline.htm in the root of the application. When ASP.NET detects the file, it will shut-down the app-domain for the application and won't restart it for requests. The app_offline.htm file will be sent as the response to all new dynamic requests for the application. When you're done updating the site, just delete or rename the file and your site it will come back online.

Taken from (or actually inspired on) this blog post of Scott Guthrie:

Keep an eye on a feature of IE6(+) called "Show Friendly Http Errors". This can be configured in the Tools->Internet Options->Advanced tab within IE, and is on by default with IE6. With this setting turned on, when a server returns a non HTTP-200 status code with less than 512 bytes of content, IE will not show the returned HTML and instead substitutes its own generic status code message.

If you use the app_offline.htm feature, make sure you have at least 512 bytes of content within it to make sure that your HTML shows up to your users instead of IE's friendly status message. If you don't want to have a lot of text show-up on the page, one trick you can use is to just add an html client-side comment with some bogus content to push it over 512 bytes. For example:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

<head>

<title>Site Under Construction</title>

</head>

<body>

<h1>Under Construction</h1>

<h2>We're currently working on our site...</h2>

<!--

Adding additional hidden content so that IE Friendly Errors don't prevent

this message from displaying (note: it will show a "friendly" 404

error if the content isn't of a certain size).

<h2>Gone to Florida for the sun...</h2>

-->

</body>

</html>

Hope this helps

"AjaxControlToolkit is undefined"

Rick van den Bosch — Thu, 23 Sep 2010 08:02:00 GMT

Because we were still using an old Visual Studio 2005 solution which included a Web Site project, it was time to upgrade. We upgraded our Visual Studio 2005 solution to Visual Studio 2010 (and .NET 4.0), converted the Web Site Project to a Web Application Project and then, of course, the AjaxControlToolkit had to follow. I downloaded the latest build from their Codeplex site and updated the references in the different projects. I ran the website, and that’s where things got ugly…

Most pages worked nicely, but there were a few that gave an “AjaxControlToolkit is undefined” error. I removed all references to the AjaxControlToolkit, removed all the old versions of it from my machine, referenced the most recent version again, all to no avail. After Googling^* Binging the error I found a LOT of possible solutions. These included:

Use the ToolkitScriptManager from the AjaxControlToolkit in stead of the built-in ScriptManager
When using the ToolkitScriptManager, set CombineScripts to false
When using the ToolkitScriptManager, set EnablePartialRendering to true
Clear the browser cache
Clear the ASP.NET Temporary Files directory
Use a (dummy) control to make sure the JavaScript files have been loaded correctly

Unfortunately, none of these possible solutions helped us with our specific problem. Our problem occurred when we, for instance, set the PositioningMode for a control from custom JavaScript using the AjaxControlToolkit.PositioningMode enumeration. The error was always from custom JavaScript. After looking around a bit more I found one site that mentioned something about changing the AjaxControlToolkit ‘namespace’ in JavaScript. After playing around a bit I found out that changing the use of AjaxControlToolkit.XXX to System.Extended.UI.XXX provided the solution.

Hope this helps.

* Of course this is a weak attempt at a joke, but fact is that Google (the first 7 or so pages) only pointed me in the direction of the solutions that weren’t solutions for my situation. When I tried Bing for a change, I found something that put me on the right track pretty fast. Kudos to Bing!

Visual Studio: Zero-impact Projects & Cutting/copying empty lines

Rick van den Bosch — Wed, 19 May 2010 16:07:00 GMT

Yesterday I remembered two Visual Studio options Sara Ford told about in a presentation of her I attended a while back. Changing them made me happy... :)

Zero-impact projects
When I have to test something real quick, I tend to create a new project in Visual Studio and scribble some code to test whatever I want to test at that point. This causes my project directory to be filled with projects named 'WindowsFormsApplication14' or something like that. To make this stop, go to Tools - Options - Projects and Solutions - General. Uncheck the option 'Save new projects when created'. This way those newly made (and shortly used) projects aren't saved untill you explicitly tell Visual Studio to do so. No more 'WindowsFormsApplication63' for you! Unless you want to name it that way intentionally, of course...

Cutting/copying empty lines
We probably all experienced this at one time or another: you select some code, copy it, go to an empty line where you want to past the code.......and you press CTRL + C by accident. With the default settings, you just copied an empty line and have lost the stuff you copied earlier. But with this next option, empty lines won't get copied or cut anymore! Go to Tools - Options - Text Editor - All languages (or just the language you want to change this setting for) and deselect the option 'Apply Cut or Copy commands to blank lines when there is no selection'.