Databases
StackOverflow2013
Postsdbo
POOdd Task Parallel Library InvalidOperationException
 

Note that there are some explanatory texts on larger screens.

plurals
  1. POOdd Task Parallel Library InvalidOperationException
    primarykey
    data
    text
    <p>I have the following code to build an advanced data structure which is pulled from SQL Server, then when the retrevial of that data is complete I update the UI. The code used is </p> <pre><code>private void BuildSelectedTreeViewSectionAsync(TreeNode selectedNode) { // Initialise. SqlServer instance = null; SqlServer.Database database = null; // Build and expand the TreeNode. Task task = null; task = Task.Factory.StartNew(() =&gt; { string[] tmpStrArr = selectedNode.Text.Split(' '); string strDatabaseName = tmpStrArr[0]; instance = SqlServer.Instance(this.conn); database = instance.GetDatabaseFromName(strDatabaseName); }).ContinueWith(cont =&gt; { instance.BuildTreeViewForSelectedDatabase(this.customTreeViewSql, selectedNode, database); selectedNode.Expand(); task.Dispose(); }, CancellationToken.None, TaskContinuationOptions.OnlyOnRanToCompletion, this.MainUiScheduler); } </code></pre> <p>This works as it should on my main development machine; that is, it completes the build of the <code>database</code> object, then in the continuation update the UI and disposes the <code>task</code> (Task object).</p> <p>However, I have been doing some testing on another machine and I get an <code>InvalidOperationException</code>, this is due to the <code>task.Dispose()</code> on <code>task</code> which still in the <code>Running</code> state, but the continuation <code>cont</code> should never fire unless the task has ran to completion. </p> <p>Here's what the code looks like in the debugger when the exception is thrown:</p> <p><img src="https://i.stack.imgur.com/CMRcg.png" alt="enter image description here"></p> <p><a href="http://blogs.msdn.com/b/pfxteam/archive/2012/03/25/10287435.aspx" rel="nofollow noreferrer">I am aware that it almost always unneccessary to call <code>Dispose</code> on tasks</a>. This question is more about why the continuation is firing at all here?**</p>
    singulars
    1. PO
      singulars
      1. PTAnswer
    1. This table or related slice is empty.
    1. PTQuestion
    1. UScasperOne
    1. USMoonKnight
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. PO
      singulars
      1. PTAnswer
    2. PO
      singulars
      1. PTAnswer
    1. VO
      singulars
      1. POOdd Task Parallel Library InvalidOperationException
      1. This table or related slice is empty.
      1. VTUpMod
    2. VO
      singulars
      1. POOdd Task Parallel Library InvalidOperationException
      1. USMoonKnight
      1. VTFavorite
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload