Web Forms :: When And Where To Write Try Catch Block
Mar 31, 2010
When to write try catch block?
Should I write it for each method or only in event handlers or ????
What happens when an exception occurrs? What is the stack for exception?
If I use it at entry point (event handlers) then how do I get actually at which line error occurred?
Suppose an exception was thrown from Data Access Layer How do I get it in presentation layer that exactly in which class method at which line why that error occurred?
Is it true that excessive use of try catch makes application slow?
Since everyone yells at me that MessageBox doesn't work when the project is uploaded to the server, I need to migrate to javascript alert box. As I was changing my MessageBoxes, I tested and found that they weren't being produced. I'm not sure if it matters, but they are in a try/catch block, which is shown here:[Code]....
This all worked before when I had MessageBox - it showed, then the page redirected when I clicked Ok.
I either don't understand how try/catch works, the javascript isn't adding, or Response.Redirect is executed before I can see the alert box and click Ok on it.
(just as a note, everything works fine, but the alert box doesn't show)........if I add the (javascript) code before the try block, the alert box comes up, so it's not something wrong with the writing of the javascript or executing it at least (I think).
Can somebody show me a better approach of looping through a Try -Catch statement. I have something like this:
Try dbConn.Open() Catch ex As Exception errmsg = ex.Message End Try
I need to try to connect 5 times before logging an error. My first thought was to nest Try - Catch 5 levels but I didn't like that idea. I'm sure there is better solution to it.
I have tried this on two different controller methods now, and both times, even if the linq2sql doesn't allow the data to be saved, the code never jumps into the catch block.
I've watched the noun object in the middle of the trace, and the isvalid property is false, but the modelstate isvalid is true. Either way, the code never jumps into the catch block.I'm pulling my hair out about this. I feel like it will be something really silly.
The code all works similar to nerd dinner.
NounRepository nounRepository = new NounRepository(); Noun noun = new Noun(); try[code]...
I'd rather not have to add code in this manner though, as it seems like an unnecessary duplication.
I have to call the function, when exception occured. Is it possible to call the function in Catch block (Try-Catch)? I have tried it but the function did not get invoked. What i have to do for it? Shall we unable to call the functions in Catch block? I have shown my code below.
Try
Catch ex As Exception ErrorHandlers.LogErrorDetails(ex, Session("UserId").ToString, "") Throw ex End Try.
I knew, We can invoke this function in Finally block but i do not need as per my requirements.
I am being told that adding a try catch block adds major performance cost in the order of 1000 times slower than without, in the example of a for loop of a million. Is this true?
Isn't it best to use try catch block as much as possible?
using (OracleConnection myConn = new OracleConnection(connectionString)) { OracleCommand myCmd = new OracleCommand("sproc", myConn); myCmd.CommandType = CommandType.StoredProcedure; myCmd.Parameters.AddWithValue("p1", a1);[code].....
Second format just doesn't feel right but I am not that experienced. I am curious if there is any downfall to that other than exception not being type specific.
I am trying to call a JavaScript function from my ascx control code behind in the catch blockI have tried the below two ways but they don't seem to work.
How/Can I Set the try, catch statment to catch a specific Error. For example i am getting the following error:
Exception Details: System.Data.SqlClient.SqlException: Incorrect syntax near '='., [SqlException (0x80131904): Incorrect syntax near '='.]
Basicly The = is part of my SQL string which points to a table that currently doesent exist. I want something like catch ex as SqlException (0x80131904) or catch ex as SqlException = "0x80131904" or even catch ex as System.Data.SqlClient.SqlException = "Incorrect syntax near '='." I just want something so i can put "table doesnt exist" in the error message without having to use:
catch ex as System.Data.SqlClient.SqlException
As i have other code on my page that could result in a different type of sqlExeption.
while doing debugging i found a blue dotted corner around catch block, while hovering it is showing system.exception...what does it mean and what to do
regarding one issue I am facing. I created a httpmodule for hadling the unhandled errors and I need to log those errors using log 4 net in database.Everting working fine but I am not getting any error information once the error was hadled and I need that info too. I want to make it as a centralize module which can trap all errors and log those errors.How call application_error event of httpmodule from catch block...so that I can log that info there and I no need log in every catch block..
In the Script documents that asp.net automatically generates how can I surround the whole generated scripts with try/catch statement to avoid 'Microsoft JScript Compilation error'
My issue is: i got a DevExpress control (ASPxGridView) that added and set-up in run time, since i activated the grouping functionality in the grid I still get JS error says ';' expected whenever i use (click) on one of grouping/sorting abilities, I activated script Debugging for IE, in the JS code turns out that there is no missing ';' and once i click ignore for the error msg that VS generates every thing works fine, and surly end-user can't see this msg so i figured out if i try/catch the script that may help avoid this error.
I need to write a query as follows which will be bound to a grid
select top 25 * from ErrTable Order by DateErrorad Desc
However, I need to write this query to return only 25 records at a time, but when a user clicks next it will display the next 25 most recent records from the db.
I have written an Http Module that hooks onto the Response.Filter property of the current request and does various replacements within the HTML before it is sent to the client.All the work is done in the Write method which is overriding Write in the base class Stream.
The Write method is called multiple times for a single response - the HTML seems to be written to the output stream in chunks. My problem is that I don't have an efficient & reliable way of telling if the current chunk is the last chunk (for why I want to know this see below). The only way I have come up with is to check if the chunk contains a closing html tag - but this is not very efficient or reliable.
The reason this is needed is that the module must add the "Refresh" HTTP header to the response, but only if the HTML fulfills certain conditions (and there are certain conditions that mean the header must not be added). So, only when the last chunk has been seen does the code know if the header can be added or not. So, I either need a test for the last chunk, or on each call to Write I add the header if the current block of HTML passes the test (if it has not already been added) or remove the header if the current block of HTML fails the test (if it has already been added).
So, is there a better way to test for the last chuck OR is there a way to test for a particular header being in the response and delete it (there doesn't seem to be a way to do this - only to append headers)?
I have menu item on my master page that has block around the text when the page is first run. I wrote in the css on the link and visited property to change the color to match the image color that it is on. When a menu item is clicked the color changes to the right color. How do I get it to the right color on when the page first opens or is there a way to get rid of the block or make it transperant?
Here is the code copied from [URL] In asp.net code behind, I use try-catch try to catch any error but never catch it. In SQL database, if I rename Employees to Employeesx or change column DepartmentID to DepartmentIDx, record will not be deleted (it is right) without any error (it is wrong, suppose catch an error).
CREATE PROCEDURE DeleteDepartment ( @DepartmentID int ) AS BEGIN TRANSACTION DELETE FROM Employees WHERE DepartmentID = @DepartmentID IF @@ERROR <> 0 BEGIN ROLLBACK RAISERROR ('Error', 16, 1) RETURN END DELETE FROM Departments WHERE DepartmentID = @DepartmentID IF @@ERROR <> 0 BEGIN ROLLBACK RAISERROR ('Error', 16, 1) RETURN END OMMIT
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.Threading.ThreadAbortException: Thread was being aborted.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
I even created a global.asax file and on the Application_Error event, I wrote a code that would email me the error (and i'm not getting an email regarding that error when I get the error shown above). I know for a fact that the thread is going inside the "try" statement because I send emails to myself whenever it finishes certain codes inside of it. So how come I'm getting that error in my browser instead of it being handled in my "catch" statement? I have two problems here, one, why is the exception not going to my "catch" statement, and two, why am I getting that error in the first place.
I have 2 separate code-block asp.Net expressions in an aspx markup, with an html content between (span element in the example below). In the first code-block, there is "i" as an increment variable for the for loop.Then the code-block is cut with an html content.And another code-block expression is opened but as I see I can reach the "i" variable which was declared in the previous code-block.
So, how asp.net handles -compiles- the pieces of code-block experrions declared in the mark up? Does it check the semi-colons and generates some anonymous methods which will end up with many calls to Response.Write in the last place? <p> <%for (int i = 0; i < 30; i++) {
So,my question is that why we basically use @ before the sql query.If I don't use @ before that then it again work fine (does not give any error), then what is need of using "@"?
I'm new to ASP.net 3.5 and creating a test web site. I have created a master page for my web site with page content blocks. Now I want to use some javascript on the client side to provide for more interaction. I would normally create page specific Javascript functions and insert them in a <script block on the page. Howevere the Javascript script block must be placed before the <HTLM block. If I'm using Master Pages, it doesn't seem that I can use page specific Javascript functions. How can I resolve this problem? I think my options are
1) Don't use Javascript. Use ? instead to write client-side code. 2) Don't use Master Pages because you cannot use Page Specific Javascript functions. 3) Here's how to insert Javascript Functions in a Page with a Master Page.
