I need to terminate the whole script execution if command let encounters the error. The whole script after that must never execute. In my case, If I use ThrowTerminatingError, it just stops the current commandlet to be executed further and the rest of the script executes which I don't want.
I already used "PipelineStoppedException" but this doesn't tell anything in the error stream and no exception can be a catch. Because Invoke call successfully terminates.
How can I achieve this? I want to terminate the whole script execution with the exception message. Following is the C# code which I am using from commandlet but it is still allowing rest of scripts to continue execution further.
Edit
protected override void BeginProcessing()
{
base.BeginProcessing();
if (SomeLogicTrue())
{
var errorRecord = PowershellErrorHandler.GetErrorRecord(new PipelineStoppedException("access is not supported for this context."), "InvalidExecutionContext");
ThrowTerminatingError(errorRecord);
}
}
Set the error action preference to "Stop" at the beginning of your script.
$ErrorActionPreference = "Stop"
Now, even if the script throws a none terminating error, it will stop at once.
I'd suggest you to read An Introduction to Error Handling in PowerShell as well.
Related
I quite often stumble about code that takes too much time for the debugger to evaluate yielding to the following annoying error:
Function evaluation disabled because a previous function evaluation timed out. You must continue execution to reenable function evaluation.
Usually we can ignore this by just stepping further, making the debugger-thread snyc to our process and then re-evaluate our statement.
However when I attach my source-code to a running, managed process, I´m unable to step any further. As soon as I get the mentioned error, no breakpoints are hit at all nor will "Break all" let me break the execution and see the currently executing statement.
The yellow line produces the error mentioned above. However no breakpoint is hit after continuing, neither by using F10 ("Step over") nor F5 ("Continue"). After this I´m completely unable to debug anything in my entire codebase.
Also when I try to break debugging to see what the process is currently doing no source-code is available nor any dissambly-information, as seen here:
I have a few methods that run one by one in a loop. To show the entire progress after every such method my BackGroundWorker is notified:
void RunTests()
{
foreach(var m in methods)
{
m.Invoke(...);
backgroundWorker1.ReportProgress(1);
}
}
private void InitializeComponent()
{
this.backgroundWorker1.WorkerReportsProgress = true;
this.backgroundWorker1.WorkerSupportsCancellation = true;
this.backgroundWorker1.DoWork += new System.ComponentModel.DoWorkEventHandler(this.RunTests);
}
The behaviour occurs inside the currently invoked method. I suppose it´s because of the other thread which the BackGroundWorker uses in order to notify the progress to the UI (in my case a progressbar), but that´s just a guess.
Has anyone an explanation or even better a solution which doesn´t need to re-start the process (which as I noticed yields to the exact same behaviour btw.).
This is because the exception is un-handled and Visual Studio cannot move past that line without it being handled in some manner. It is by design.
Continuing in the Visual Studio debugger after an exception occurs
I'm executing a PowerShell script in C# using the "PowerShellInstance" class but I'm having an issue with the commandlet "Clear-Host". I get some errors related to the fact that the host program or the command type does not support user interaction.
However, it must be possible to execute this script directly via PowerShell (without using C#), therefore, I want the "Clear-Host" command to execute only if the script has been triggered from within a PowerShell windows and not when it's triggered from the C# code.
So far, the only way I found is to wrap it in a "Try { } Catch { }" block but I'm wondering if there is a better solution... Something like "if ($host.IsOk) { }".
Thanks
OK, if I understand correctly, you want something like this:
if($host.UI.RawUI.WindowTitle -match "PowerShell")
{
Clear-Host
}
else
{
"The script was executed from C#"
}
I was wondering whether if it was necessary to keep a return statement after my Response.RedirectPermanent call in my codebehind? It doesn't seem like it, but I wanted to confirm with others.
Response.RedirectPermanent(vpd.VirtualPath);
return;
Is there any reason to do so either for a functional or performance gain?
Answer overhaul:
Hold the phone! The detail in my previous answer was, following further research, not at all true. In fact, the MSDN documentation specifies the following:
When you use this method in a page handler to terminate a request for one page and start a new request for another page, set endResponse to false and then call the CompleteRequest method. If you specify true for the endResponse parameter, this method calls the End method for the original request, which throws a ThreadAbortException exception when it completes. This exception has a detrimental effect on Web application performance, which is why passing false for the endResponse parameter is recommended.
http://msdn.microsoft.com/en-GB/library/a8wa7sdt.aspx
So, in actual fact, the rest of the page is not executed (in theory - see 'Update' below for an example of when this falls over); however, there is still a very tangible issue with doing it the way you are, which is that the endResponse mechanism is implemented by throwing a ThreadAbortException, which is a relatively expensive way of terminating the processing of the current thread.
Instead, you should tell it to let the thread continue, but return immediately - also be sure that other methods in the call stack are doing what they should:
Response.RedirectPermanent(vpd.VirtualPath, false);
return;
Better yet, wrap the call in a conditional to ensure that undesirable code doesn't get called and then use the CompleteRequest method (which does not terminate the currently-executing code but will bypass all subsequent events):
if (_redirecting)
{
Response.RedirectPermanent(vpd.VirtualPath, false);
Context.ApplicationInstance.CompleteRequest();
}
else
{
/* Code I don't want to execute if I do a redirect */
DeleteUsersDataForever(_currentUser);
}
There's an in-depth article on this very topic here and even the documentation itself seems to have an unhealthy distaste for the HttpResponse.End method, which is what's called if you allow Response.Redirect to do the response termination for you.
Update: Additionally, given that the thread is terminated by raising an exception, consider what happens if you try and do your redirect inside a try/catch:
try
{
// Redirect and terminate execution
Response.Redirect(someUrl, true);
}
catch
{
// Handle some errors.
}
DeleteUsersDataForever(_currentUser);
The exception that's raised by Response.End is caught in your catch block. The rest of your code is, therefore, still executed and you have accidentally deleted all of _currentUser's data (unless you do something to prevent this in your catch block, such as bubbling the exception to the caller).
I have tried the code below :
Page1.aspx
protected void Page_Load(object sender, EventArgs e)
{
Response.RedirectPermanent("~/Page2.aspx");
Session["afterRedirect"] = "after redirect";
}
Page2.aspx
protected void Page_Load(object sender, EventArgs e)
{
Response.Write(Session["afterRedirect"] ?? "nothing to show");
}
Result
nothing to show
Code after RedirectPermanent does not execute so Iguess using a return or not will have the same effect.
I have gone through MSDN.But could not understand properly about the method mentioned below.
What does the below code do if it is included in an SSIS script destination component?
bool Error = false;
this.ComponentMetaData.FireError(0, "myScriptComponent",
"`A Transformation error occurred. Check the corresponding Text File ",
"", 0, out Error);`
The FireError method allows you to raise an error that is consistent with the built in error handling methods used elsewhere in SSIS. I.e. the above code raises an error that is picked up by the OnError event.
The parameters that follow the FireError method are described on BOL.
This can be used to provide adequate error handling (which you always should do when writing any custom code). E.g.:
Try
'Your Code Here
Catch
'Error handling here
Me.ComponentMetadata.FireError(...)
end try
In addition to .FireError, the additional .Fire... methods allow you to fire similar events that will be picked up by SSIS, e.g. .FireInformation allows you to write messages to the output window.
In my custom data flow component, I have overriden the OnOutputPathAttached method. I want outputs to be attached under certain conditions. ie:
public override void OnOutputPathAttached(int outputID)
{
if (/*condition*/)
{
//do some processing
base.OnOutputPathAttached(outputID);
}
else
{
System.Windows.Forms.MessageBox.Show("Error message");
//CODE TO STOP OUTPUT FROM BEING ATTACHED???
}
}
What should I put so that the output isn't attached? For now it shows the error message but still attaches the output.
I suspect that it's too late to stop the user from attaching a path by the time your OnOutputPathAttached method is called. (At least, that's how I'm reading the MSDN page on the AttachPathAndPropagateNotifications method.)
Your best bet seems to be to return VS_ISBROKEN from your Validate method, along with raising useful OnError events.