Blog

Below are the ten most recent posts from my blog, mirrored from the original at bloggingabout.net/blogs/rick.

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

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

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

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

Debugging JavaScript with Visual Studio in an ASP.NET MVC 4 application

When debugging JavaScript in an ASP.NET MVC (4) application, it is not always enough to uncheck the 'Disable script debugging' checkboxes under 'Tools' - 'Internet Options' - 'Advanced' - 'Browsing'. JavaScript inside a Razor view (a cshtml file) cannot be debugged from Visual Studio. To debug your JavaScript, move it to a separate .js file and link to that file from your Razor view. This way, breakpoints set in the JavaScript will be hit and you can debug from Visual Studio.

Hope this helps

 

Disclaimer: I know about the F12 Developer Tools, Firebug and all the other possibilities we have to debug JavaScript. This post is about getting JavaScript debugging to work with Visual Studio and breakpoints set in Visual Studio. For those who want it that way. So there... ;)

How To: Call a generic method with a runtime type

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

Enable preview in Visual Studio 2012 after Update 1

After installing Visual Studio 2012 Update 1, my Visual Studio stopped opening files in preview mode when I clicked them in the Solution Explorer. This setting seems to have changed with the installation of Update 1. To re-enable opening files clicked (once) in the Solution Explorer in Preview mode, go to ‘Tools’ – ‘Options’ – ‘Environment’ – ‘Tabs and Windows’.

There, check the box under ‘Preview Tab’ – ‘Single-click opens files in the preview tab in:’ – ‘Solution Explorer (Alt + click to avoid previewing)’.

Hope this helps

EDIT:
This is a lot easier: the 'Preview Selected Items' button in the Solution Explorer toolbar:

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

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

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."

Microsoft Touch Mouse, Visual Studio (2012) and scrolling

My Microsoft Touch Mouse stopped scrolling in Visual Studio on my Windows 8 machine some time ago. Because this kills productivity, I wanted to fix the problem. After trying some things I found that the problem only occurred when I ran Visual Studio as Administrator. Searching a bit further I found this bug to be added to Microsoft Connect. I found a workaround for the problem:

• Go to the location where you have Microsoft Mouse and Keyboard Center installed
• Open up the properties of ipoint.exe
• Set it to Run as Administrator
• Kill and restart ipoint.exe (or restart the machine)
• Welcome back scrolling in Visual Studio…!

Hope this helps

HowTo: Have Visual Studio always run as administrator on Windows 8

In my previous post I wanted my Visual Studio to ‘Run as Administrator’ on my Windows 8 machine. I only managed to get this working for the pinned taskbar icon and not for items in the jumplist or for items you open by double clicking them. The solution to check the box ‘Run as Administrator’ on the compatibility tab of the file properties for devenv.exe was not a solution, because there is no more Compatibility tab in Windows 8 :).
But there is a way to have devenv.exe always ‘Run as Administrator’. Here’s how:

• Right click devenv.exe en select Troubleshoot compatibility (first picture)
• Select the option ‘Troubleshoot program’ after the wizard has finished detecting issues
• Choose the ‘The program requires additional permissions’ option (second picture). The wizard will apply the ‘Run as Administrator’ setting to devenv.exe
• Click ‘Test the program…’ (third picture - the wizard requires this) and close the wizard
• Enjoy!

 

   

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