I have this sample code for async operations (copied from the interwebs)
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Other async approaches I tried required the aysnc page attribute, they also seemed to cancel if other page elements where actioned on (a button clicked), this approach just seemed to work.
I'd like to add a cancel ability and exception handling for the longRunningTask class, but don't erm, really know how.
If an error happens in the DA_layer, how do I pass it do the code_bedhing to show the user?
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i have this application structure:
1. Presentation Layer which calls
2. Business Logic Layer which in turn calls
3. Data Access Layer to do the dealing with the database.
Now i have a Contacts page from where i can add a new contact to the database.So to add a New Contact i fill in all the required details and then call a Add Method (residing in the BLL) from the page, which in turn call a Add Method residing in the DAL.this method in the DAL returns the Current Identity of the record which is then return back to the BLL method and finally delivered on the page.this is fine. but what if a get an exception how do i handle it properly because the method in DAL has a return type of int and i dont want to throw another error!! coz other wise i will have to write try catch in almost all the methods.
//something like this
public int AddMethod(ContactClass contactObj)
{
int result = 0;[code]...
rather i want to show the user a user-friendly message which they can easily understand and in the mean while i will send a mail to myself documenting the Error that just occurred.how can i implement my custom exception classes.
For example, I am using wenclient.DownloadfileAsync to download a file asynchronously.
In the DownloadFileCompleted event handler, I can check if I have any exception or not by using AsyncCompletedEventArgs.Error property.
If I re-throw this exception, however my executable is stopping running immediately.
I am wondering how to handle this kind of exeception? How to pass this exception back to the
calling thread?
i'm using asp.net 2.0 form with ajax. i have an ihhtpmodule which can thrown an exception at Application_EndRequest step. my problem is that if this happen in an async postback (i mean a postback of an update panel) i can't manage the exception (with manage i mean set a custom error message server-side) becouse it's too late for the error handler of the ScriptManager.
(the alert will print a message as:
Sys.WebForms.PageRequestManagerParserErrorException: The message received from the server could not be parsed. Common causes for this error are when the response is modified by calls to Response.Write(), response filters, HttpModules, or server trace is enabled.
Details: Error parsing near 'MyButt" />
|<html>
<head>)
at the moment my idea is to clear the response in the module and find a way to use the scriptmanager to send the correctly response of an error/exception. it's this possible? or samebody has another option of how to manage this case? note:i can't edit the aspx to manage this client client side with custom javascript
It has to do with the RowCommand 'Cancel'. When clicking on my Edit button for a row, the GridView puts the row into edit mode without a problem (I have no code for the Edit command, I let the control do everything).
Once in Edit mode, if I click the Cancel button (again, I have no code handline this RowCommand, I let the control handle it (like i do with many other GridViews)) I get the following exception:
"System.InvalidOperationException: Databinding methods such as Eval(), XPath(), and Bind() can only be used in the context of a databound control."
I created a simple data access layer in the dll and reference it in my web app. How can I point the error to the user that his code in this line has an exception. currently, when i input a nonexisting table it will popup an error "invalid object name table_name" and points the my code throw exception inside my dll. I want it to point out to the user code that uses my function that creates an error.
Line 92: Dim ds As DataSet = DAL.Dal.ExecuteDataset("SELECT * FROM table_nam", "DBConnectionString")
Line 93: GridView1.DataSource = ds.Tables(0)
Code:
public static void Test()
{
try
{
OpenConnectionToDatabase(); //Opens a connection to Oracle DB
} catch(Exception e)
{
e.Data.Add("Query:", command.CommandText);
throw e;
}
}
When this code is executed when the Database server is being shutdown and the communication is disrupted, .NET throws the following error: Item has already been added. Key in dictionary: 'Query:' Key being added: 'Query:' at System.Collections.ListDictionaryInternal.Add(Object key, Object value) How can this be?
I'm wondering what's the preferred way to manage exceptions in an MVP implemented with a Passive View.
There's a discussion in my company about putting try/catch blocks in the presenter or only in the view.
In my opinion the logical top level caller is the presenter (even if the actual one is the view).
Moreover I can test the presenter and not the view. This is the reason why I prefer to define a method in the view interface:
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We are using renderaction provided by MVC futures. We've noticed that HttpExceptions in child action methods are not propagated to the parent action. Even though a fragment has failed, we still see the parent request resulting in a 200, and this throws our error handling for a toss.
View 4 RepliesI have a weird situation here. Using VS2010 and the MVC2 application template, I'm trying to set up error handling, but it refuses to work... Even with a simple controller throwing an exception in the index:
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And <customErrors mode ="On"></customErrors> in the web.config file, MVC breaks into the code and tells me that "Exception was unhandled by user code". The default Error.aspx (static text only) is located in /Views/Shared, and I've even removed the login partial view from the master page.
I have a code which reads from a database and loads all feeds in it. Occassionaly I will get errors when the feeds are not responding. The error is happening on this line of code:
[Code]....
How do I add in a code that if the read above fails, ignore and proceed to next data row in the SQLDataReader ?
iam inserting record in three tables in a database, iam using begin trans , commit transaction and rollback,
i want to use throw method, if any value insert wrong, pls correct me, i want to throw the error and
its go to rollback
running = false;
int updaterec = DBmgr.ExecuteNonQuery(CommandType.Text, "update ASArrivedcontainer set billgen ='Y' where billgen ='y' and acontinerid in ("+SelValues+")");
if (updaterec > 0)
{
running = true;
DataSet BillContainerDetails = BillingDetails();
byte[] ContainerDetails = GenerateBill(DBmgr, sContainerIds, rcno,isGeneralRCNo, FetchContainerDetails, ModifyId,ref BillContainerDetails);
DBmgr.CreateParameters(6);
//string otherchargesId = obj.retriveSingleRecord("select top(1) ModifyId from ASOtherCharges");
DBmgr.AddParameters(0, "@InvoiceNo", "1","IN");
DBmgr.AddParameters(1, "@BillDate", DateTime.Now.ToString("yyyy/MM/dd hh:mm:ss tt"), "IN");
DBmgr.AddParameters(2, "@CustomerId", "1", "IN");
DBmgr.AddParameters(3, "@TotalAmount", "10000", "IN");
DBmgr.AddParameters(4, "@OtherChargesId", ModifyId, "IN");
DBmgr.AddParameters(5, "@ContainerDetails", ContainerDetails, "IN");
String BillNo = DBmgr.ExecuteScalar (CommandType.Text, "Insert into BillMaster(InvoiveNo,BillDate,CustomerId,TotalAmount,OtherChargesId,ContainerDetails) values (@InvoiceNo,@BillDate,@CustomerId,@TotalAmount,@OtherChargesId,@ContainerDetails)
Select @@Identity ").ToString();
if (!String.IsNullOrEmpty(BillNo))
{
running = true;
DBmgr.CreateParameters(4);
for (int i = 0; i < BillContainerDetails.Tables[0].Rows.Count; i++)
{
BillContainerDetails.Tables[0].Rows[i]["BillNo"] = BillNo;
DBmgr.AddParameters(0, "@Billno", BillContainerDetails.Tables[0].Rows[i].ItemArray[1].ToString(), "IN");
DBmgr.AddParameters(1, "@rcno", BillContainerDetails.Tables[0].Rows[i].ItemArray[2].ToString(), "IN");
DBmgr.AddParameters(2, "@acontinerid", BillContainerDetails.Tables[0].Rows[i].ItemArray[3].ToString(), "IN");
DBmgr.AddParameters(3, "@bflag", BillContainerDetails.Tables[0].Rows[i].ItemArray[4].ToString(), "IN");
//string value = BillContainerDetails.Tables[0].Rows[i].ItemArray[0].ToString(); ;
// string strsql = "insert into billcontinerdetail(billno,rcno,acontinerid,bflag) values(@billno,@rcno,@acontinerid,@bflag)";
String count = DBmgr.ExecuteScalar(CommandType.Text, "insert into billcontinerdetail(billno,rcno,acontinerid,bflag) values(@billno,@rcno,@acontinerid,@bflag)Select @@Identity").ToString();
if (count > 1)
{
running = true;
}
else
{
}
//running = true ;
//break;
}
DBmgr.CreateParameters(6);
for (int j = 0; j < BillContainerDetails.Tables[1].Rows.Count; j++)
{
DBmgr.AddParameters(0, "@billcontkey", BillContainerDetails.Tables[1].Rows[j].ItemArray[1].ToString(), "IN");
DBmgr.AddParameters(1, "@ratetypcode", BillContainerDetails.Tables[1].Rows[j].ItemArray[2].ToString(), "IN");
DBmgr.AddParameters(2, "@days", BillContainerDetails.Tables[1].Rows[j].ItemArray[3].ToString(), "IN");
DBmgr.AddParameters(3, "@amount", BillContainerDetails.Tables[1].Rows[j].ItemArray[4].ToString(), "IN");
DBmgr.AddParameters(4, "@level", BillContainerDetails.Tables[1].Rows[j].ItemArray[5].ToString(), "IN");
DBmgr.AddParameters(5, "@sflag", BillContainerDetails.Tables[1].Rows[j].ItemArray[6].ToString(), "IN");
// string strsql = "insert into billratedetail(billcontkey,ratetypcode,days,amount,level,sflag)values(@billcontkey,@ratetypcode,@days,@amount,@level,@sflag)";
String count = DBmgr.ExecuteScalar(CommandType.Text, "insert into billratedetail(billcontkey,ratetypcode,days,amount,level,sflag)values(@billcontkey,@ratetypcode,@days,@amount,@level,@sflag)Select @@identity ").ToString()
;
A first chance exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll An exception of type 'System.Threading.ThreadAbortException' occurred in mscorlib.dll but was not handled in user code
After banging my head because i could find where the exception came for and global.asax didn't get hit i found that it's from server.transfer and is a known bug. The alternative i read about is server.execute.However if i do this then the next page fires multiple javascript exceptions and a gridview i have is breaking of and the rows appear half at the left page corner and half inside the gridview!!
For now i just put a try catch on the server.transfer although the exception will not affect the application even if i don't use try catch. I also see that the exception is happening again even if i put try catch but with different dll: A first chance exception of type 'System.Threading.ThreadAbortException' occurred in App_Web_benglxq1.dll An exception of type 'System.Threading.ThreadAbortException' occurred in App_Web_benglxq1.dll but was not handled in user code Now what on earth is benglxq1.dll i don't know. What i know is that i'm leaving an exception to run and i don't like that. This is the js error when i use server.transfer btw: Microsoft JScript runtime error: Sys.ArgumentTypeException: Object of type 'Sys._Application' cannot be converted to type 'Sys._Application'.
When I do ThreadPool.QueueUserWorkItem, I don't want unhandled exceptions to kill my entire process. So I do something like:
ThreadPool.QueueUserWorkItem(delegate() {
try { FunctionIActuallyWantToCall(); }
catch { HandleException(); }
});
Is this the recommended pattern? It seems like there should be a simpler way to do this. It's in an asp.net-mvc app, if that's relevant.
I devide my website on 3 layers :
DAL(Data Access) - simple extract data from DB using LINQ
BLL(Business Logic) -
cache data and in try/catch block call function from DAL and throw it to UI :
try
{
}
catch (Exception ex)
{
//Log error
throw ex
}
UI (User Interface) - simple working without handling any exception,
So if error occured in BLL i will be redirected to Error.aspx page with message that something wrong.
how and where handle exceptions, or may be exists common patter where handle and how to inform user about errors ? Can anybody share bes practice.
My manager designed a table exactly like this
[Exception]
PK | ExceptionId
ExceptionCode varchar(100)
ExceptionDesc varchar(255)
ExceptionMSG varchar(255)
I'm using ASP.NET Webforms and using stored procedures/ADO.NET for DataAccess. Now he does not want me to hard code validation in stored procedures nor in the code behind, but to catch the constraint exception message and look up the same error message in the database and look for the message that we want to show. I wonder if his design will work or should I explain to him that something is wrong here.
I am writing a exception handling for errors on my application in the "
Sub Application_Error(ByVal
sender As
Object,
[code]...
After many years reading this forum... I didn't found the solution to my actual problem... When I tought... this could be a big problem... I have a web app wich doesn't have try catch blocks in every method... so I need to implement a generic solution to handle exceptions and the most important... show some BO exceptions to user inside a MessageUserControl (ASCX) wich uses AJAX. this is the big problem, I tried many solutions, application_error, a specific log module, page_error... and with all I got to the same problem...
The UpdatePanel, when it got an unhandled exception, it fires the events (application_error, page_error) or even the httpmodule, but I think it call an Response.End, wich stops any action in the page... and this is just I don't want to do... I need to display the message to the client. this is the call to show the message...
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My page wich gots an unhandled exception are inside an UpdatePanel, if I remove it, the message shows UP! I'm working on this for 5 long days.
i am having trouble catching errors in an AJAX panel. Even when i throw an exception in the c# code behind the front end completely ignores it. Here is the code i have setup, can anyone see why? I ideally want to show a js alert window on error.
protected void btnX_Click(object sender, EventArgs e)
{
throw new ApplicationException("test");
}
protected void ScriptManager_AsyncPostBackError(object sender, AsyncPostBackErrorEventArgs e)
{
ScriptManager.AsyncPostBackErrorMessage = e.Exception.Message;
}
Markup:
<script type="text/javascript" language="javascript">
Sys.WebForms.PageRequestManager.getInstance().add_endRequest(EndRequestHandler);
function EndRequestHandler(sender, e)
{
window.alert(e.get_error().name);
}
</script>
<asp:ScriptManager ID="ScriptManager" runat="server" AllowCustomErrorsRedirect="true" OnAsyncPostBackError="ScriptManager_AsyncPostBackError" />
I am going to be receiving data in a web service. After I receive this data I will be mapping it to a data transfer object. I want to be able to catch exceptions if the data from the service is missing any of the required values, times out or any data is malformed.
What can I do to generally catch these exceptions?
I'm currently working on a 3-tier ASP.NET application (UI, BLL & DAL). The DAL uses a strongly typed dataset that I've created with the VS Dataset Wizard. My question is, what is the best way to handle exceptions originating from the BLL and DAL classes. I googled a bit and it seems that the most commonly used practice is to create DALException and BLLException classes and throw your own message. Is this the way forward? how this can be done for an automatically generated DAL? What are the best practices?
View 1 RepliesI have introduced site wide exception handling on my site to catch unexpected errors. The event handler sends a message to me when such an exception occurs. But the problem is that any clicks on my site will cause an exception to be thrown with the message: "This is an invalid webresource request."
I googled for an answer and only found a couple of references to 1. setting a fixed machinekey (which for some reason didn't work for me, I got an error saying that the virtual directory wasn't set in IIS, and as far as I know I'm not using IIS at all, I'm using the local development environment and then deploy to a web host) or 2. using a robots.txt file to stop robots from accessing the axd files, but that doesn't help either because it's not robots that cause the problem, anyone clicking around on the page will cause this error. how to solve this problem properly? For now I have handled it by catching and ignoring this particular error by the text in the error message, which works but I would rather fix it so that this error doesn't occur at all.
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I'm a new bie in ajax controls and need your help. I've used Ajax control toolkit controls and update panel in one of the asp .net web application.
The application works fine with no problem as such but, now I have to implement exception handling in it.
I found that whenever an exception occurs in code behind the exception details shown in firefox or IE is:
"Error: Sys.WebForms.PageRequestManagerServerErrorException: An unknown error occurred while processing the request on the server. The status code returned from the server was: 500"
What I want to achieve is to rediect user to another page say SendError.aspx with actual details of exception. This way user can send the error to web admin via email.
Ps: I'm not looking for cause of error 500 just looking for "how to handle expections gracefully and redirect to another page"
I am trying to write a webservice that's going to be used through ASP.Net Ajax. In this webservice I have to add exception handling so that in case of any error, I could log them to some central place and then throw.
In my other areas of code (like aspx pages), i have been using a basepage which Overrides System.Web.UI.Page class's OnError by adding a custom event handler. I want to do the same for my webservice as well.
Basically I do not want to decorate each webservice method with a Try Catch block. Instead if there is a clean way like to override the on error method, i want to go for that. Unfortunately the WebService class does not seem to have any functionality for this.
