C# .NET

VS 2008 crashes when running unit tests - VSPERF?

Tim Huffam — Tue, 26 Aug 2008 21:36:21 GMT

Sometimes Visual Studio 2008 (Team System Developer Edition - with Team Explorer and TFS Power Tools) crashes (disappearing completely) when running unit tests.

I have not yet tried SP1 for VS2008 - will hopefully try this in the next week or two.

Not really sure what causes this - but have noticed that the following error is written to the windows event log prior to the crash (not at the same time).

Event Type: Error
Event Source: VSPERF
Event Category: None
Event ID: 1406
Date:  22/08/2008
Time:  16:27:18
User:  N/A
Computer: MYPC
Description:
There was an error connecting to the Logger Engine while registering C:\Dev\DEV\Release1\Source\MyWebProject\bin\MyWebProject.dll for coverage.

Initially I thought it was a particular test or peice of target code that caused it, but found that the crash occured at seemingly random moments ie I tried running all tests and it would crash at test number 259 (out of 264), then tried running the first 100 tests and it crashed - then tried the last 20 tests and it crashed- even tried running 1 test and it crashed. This was the worst case of this problem - over the past few weeks it (VS crashing/disappearing) would only happen every now and then.

The only work around I've found is to replace or remove the workspace and start again...

If you have pending changes, shelve them first.
Using Source Control Explorer, remove the workspace.
Close the solution in VS.
Within a VS command prompt run the following command to remove all workspaces (if you have many workspaces and only want to remove the one workspace then specify it's name instead of the asterisk used below):
tf workspaces /remove:*
Use the Source Control Explorer to recreate a new workspace.
Note: if you have scripts/macros that reference your original workspace source dir, then it would pay to use the same dir - if you do, make sure you delete the contents of this dir before reassigning it to the new workspace.

HTH
Tim

VS2008 Javascript debugging error: The breakpoint will not currently be hit. No symbols have been loaded for this document

Tim Huffam — Sun, 17 Aug 2008 22:04:24 GMT

When trying to debug javascript using Visual Studio 2008 there a couple of things you need to do first - otherwise it (debugging) will not work and you'll get the following error when you hover over breakpoint in your javascript:

The breakpoint will not currently be hit. No symbols have been loaded for this document.

Note that this is only for debugging using IE (6) - not sure about other browsers/versions.

Within IE go into Tools - Internet Options - Advanced tab and make sure the 'Disable Script Debugging' is unchecked.
Make sure you have a breakpoint in your javascript.
Start debugging your web app in VS.
Within VS select menu item Debug - 'Attach to Process...'
On the Attach to Process dialog, select the row which has explorer.exe for your app (the Title column will have you page title on it), then click Attach.

That's it - when your breakpoint is reached the VS debugger will be triggered.

HTH
Tim

How to find out what the client (browser) is posting back to the server (with ASP.NET C#)

Tim Huffam — Thu, 24 Jul 2008 01:43:51 GMT

For those of you wanting to know just what is being sent (posted) back from the client (browser) to the server (ASP.NET) - when a postback occurs - use the following lines in your C# ASP.NET program:

string msg = "";
for (int i = 0; i < Request.Form.AllKeys.Length; i++)
{
msg += i.ToString() + " " + Request.Form.GetKey(i) + ": " + Request.Form[Request.Form.GetKey(i)] + "\r\n";
}
System.Diagnostics.Debug.WriteLine(msg);

Either look at the output window or put a break-point on the last line so you can use the debugger to view the variables values at runtime.

Note that this only the information within the HTTP POST payload. There are also things like the HTTP headers, cookies etc (all of which you can query in a similar fashion - all within the Page.Request object).

Normally I'd use a tool like Fiddler for this type of interogation - but sometimes it's just as quick and easy to do it in the code like this.

HTH

Tim

ASP.NET 3.5 controls not being rendered

Tim Huffam — Wed, 09 Jul 2008 10:50:56 GMT

For some reason some controls/tags within ASP.NET do not always get rendered/passed to the client.

This has happened to me on a number of occasions. It seems limited to <style> and <script> tags - but happens for both raw HTML (within the aspx designer) and dynamically created tags (eg using new HtmlGenericControl("style")...).

This is happening to controls/tags within AJAX updatepanels within, webforms and usercontrols.

Sometimes I can work around this by simply placing these controls/tags some where else within the page structure. But the most consistent way to get around this issue is to place a non-blanking space before the tag eg:

 <style>...

Another half-baked solution hit's the road ;-)

Update:

After some investigation, I have found a not-so-half-baked solution - for getting javascript loaded and run on a page during an AJAX postback...

The solution is to not try and add a script tag by adding it to a control within the page - but rather use the ASP.NET AJAX ScriptManager class's RegisterStartupScript() method. There are two overloads for this, one loads/registers the script and runs it just once (initial page load) and the other on each asynchronous postback (the latter suited my needs).

HTH
Tim

Javascript error using Telerik controls with ASP.Net: Error: 'Telerik' is undefined

Tim Huffam — Tue, 08 Jul 2008 21:03:48 GMT

The following javascript error occurs when trying to use the Telerik controls and you haven't updated your ASP.NET (2.0) web.config file correctly.

Error: 'Telerik' is undefined

To fix make sure the following lines are within the <system.web> section of your web.config file:

In my case I was missing the ScriptResource.axd line. Also, you only need the ChartImage.axd line if you're using the chart control.

HTH
Tim

Visual Studio (VS200) loosing it's source control bindings

Tim Huffam — Wed, 11 Jun 2008 23:08:41 GMT

VSTS2008 has, on occasion, lost it's source control settings - specifically, the bindings to TFS server for a given solution and it's projects.

This seems to be because the solution and project files are not being updated when you use the TFS Source Control Explorer to do a 'Get Latest' - a 'feature' of VS2008 which allows you to work disconnected/offline - however it seems to have an issue trying to reconnect itself.

To resolve we simply removed the local source directory and did a 'Get Specific Version - get latest'.

RickSW had a similar experience.

Tim

Dundas chart error databinding: Series data points do not support values of type "myclass", only values of these types can be used: Double, Decimal, Single, int, long, uint, ulong, String, DateTime, short, ushort.

Tim Huffam — Wed, 11 Jun 2008 20:23:59 GMT

The following error can occur when executing the .DataBind() method on a Dundas chart object within an ASP.Net page (.Net 3.0):

Series data points do not support values of type "myclass", only values of these types can be used: Double, Decimal, Single, int, long, uint, ulong, String, DateTime, short, ushort.

I had set the DataSource property to a generics List of myclass objects (List<myclass>).

It turns out that this error is caused by a mismatch between the type of objects within the list passed to DataSource and the series defined for the chart.

In my case I had create 4 series but the objects within the list only had 3. I'm guessing the same error would also occur if the property names of these objects to not match the series .ValueMembersY/ValueMemberX property settings.

HTH
Tim

Checking ExpectedException and is thrown by specified type

Tim Huffam — Fri, 06 Jun 2008 04:19:22 GMT

Using the VS2008 unit testing framework, if you want to check for an expected exception, sometimes your test will pass because the exception was raised by another line of code - after the line you were specifically trying to test.

To resolve this you have to manually check for the expected exception - using a try-catch block.

However there is a catch (excuse the pun)....

Microsoft.VisualStudio.TestTools.UnitTesting.Assert.IsInstanceOfType() will not fail when types are different as long as the actual value is of a type within the inheritance hierarchy of the expected type.

Eg the following assertion will not fail if ex is of type ArgumentNullException - as it inherts from ArgumentException.

Assert.IsInstanceOfType(ex, typeof(ArgumentException));

One solution is to create your own assertion method eg:

public static void ExpectedExceptionThrownByType(Type expectedExceptionType, Exception actualException, Type expectedThrownByType)
{
Assert.AreEqual(expectedExceptionType, actualException.GetType());
Assert.AreEqual(actualException.TargetSite.DeclaringType, expectedThrownByType, "Expected exception to be thrown by type " + expectedThrownByType.ToString() + " but was " + actualException.TargetSite.DeclaringType.ToString());
}
Note the first assertion uses AreEqual instead of IsInstanceOf() - this makes sure the exception is of a specific type (rather than any one up the inheritance heirarchy).

System.ObjectDisposedException: Cannot access a disposed object. Getting Linq to prepopulate/explicitly fetch data from the database.

Tim Huffam — Mon, 02 Jun 2008 21:41:57 GMT

Exception: System.ObjectDisposedException: Cannot access a disposed object.

Object name: 'DataContext accessed after Dispose.'.

This can occur when using Linq to SQL to retrieve data from a database - and when you try to access data after the data context object has been disposed. More specifically, the exception occurs when trying to access an item that has not yet been retrieved from the database and the data context object has been disposed.

This often occurs when using a variable, that was populated within a using(...datacontext) block, after the using() block. This works fine when accessing data explicitly retrieved within the using() block - but the exception occurs when you try to access other items that were not retrieved eg a related item such as a foreign key or child table.

To reproduce this error, comment out lines 6 and 9 in the sample code below. This will raise the exception on line 11.

We can be solve this by telling the data context to explicitly retrieve the items you'll need. This can be done a number of ways while the datacontext is still in scope.

Access the items directly eg with a linq expression eg something followed by .ToList(), .Single() or .First(). Line 9 does this in the sample below.
Use the DataLoadOptions class - this is a way of telling the datacontext what additional data to retrieve. Lines 4, 5 and 6 do this in the sample below (6 is commented out just while testing line 9).

* Note that you only need one of these - so either include lines 4-6 (all uncommented) or line 9.

The following code shows how to do both. This is based on a database using a table called Parent and a table called Child. The Child table has a ParentId field that is a foreign key to the Parent table. The DataClasses1DataContext was generated using Linq to SQL.

1. Parent outerParent;
2. using (var db = new DataClasses1DataContext())
3.  {
4.   DataLoadOptions dlo = new DataLoadOptions();
5.   dlo.LoadWith<Parent>(p => p.Childs);
6.   //db.LoadOptions = dlo;
7.   var outerParent = (from parent in db.Parents
8.                     select parent).First();
9.   List<Child> children = outerParent.Childs.ToList();
10. }
11. int i = outerParent.Childs.Count;

HTH

Tim

Cannot change column to Not Null: Cannot insert the value NULL into column '', table '.dbo.Tmp_'; column does not allow nulls.

Tim Huffam — Thu, 29 May 2008 09:05:03 GMT

When modifying a table SQL Server (2005) and unchecking a column's 'Allow Nulls' (ie trying to make the column Not Null) the following error may occur:

'<tablename>' table
- Unable to modify table.  
Cannot insert the value NULL into column '<columnname>', table '<dbname>.dbo.Tmp_<tablename>'; column does not allow nulls. INSERT fails.
The statement has been terminated.

This occurs if there is already data in this table and this column contains nulls.

The solution is to simply update the data in this table so that this column does not contain nulls then change the column to not null. eg if this column was of type int you could do this:

UPDATE [<dbname>].[dbo].[<tablename>]
SET [<integercolumnname] = -1