.net - Why Does Custom HttpResponse Throw Exception On HttpResponse.End()
Jul 27, 2010
I'm writing some code in which I need to use my own HttpResponse object to capture the output from a method on another object that takes an HttpResponse as a parameter. The problem is, this other object (which I cannot modify) calls HttpResponse.End(), which causes an "Object reference not set to an instance of an object" exception to be thrown. What can I do about this?
Dim myStringbuilder As New StringBuilder
Dim myStringWriter As New IO.StringWriter(myStringbuilder)
Dim myResponse As New Web.HttpResponse(myStringWriter)
[code].....
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Sep 2, 2011
I'm using the following code to generate a CSV file containing data from a dataset. The CSV generates fine and a prompt box displays so that the user can either open or save the csv file. What I'm wondering is whether it's possible to save the CSV file?
Edited with solution (NB I don't need the prompt box to open as I'll be writing additional code to generate and save a number of files and then display links to them). This saves the dataset as a CSV on our server.
Protected Sub exportBtn_click(ByVal sender As Object, ByVal e As System.EventArgs)
Dim ds1 As DataSet
ds1 = csvdownload.ReturnNewPledges()
[Code]....
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Nov 15, 2011
MVC 3. VB.NET I have the following controller action in my application to send generated PDF files to the User by download. The function works fine when the controller itself has been invoked. But when I call to the function from outside the controller it returns a " Object reference not set to an instance of an object " error as soon as it hits the response.contenttype line. I have verified that all of the variables are in fact making it to the below action.[code]any ideas why this is only working when called explicitly from inside its containing controller???
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Aug 4, 2010
HttpResponse.RemoveOutputCacheItem Method (String)
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Dec 16, 2010
I cannot read filename in response header:Content-Disposition: inline; filename="
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May 8, 2009
It is possible to catch an exception and throw a new exception which wraps the first exception as an inner exception: [URL] Also, if I call a function and it throws a certain error, but I catch it, will the calling code's catch handler execute? If so, and it is of a higher exception type, is this not wrapping the exception? eg I can throw exception ex of type IndexOutOfRange, log it but rethrow, catch a higher up exception and do something, or I can throw a new exception and wrap an inner exception like:
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Jun 26, 2009
I ran into an interesting dilemna today. I have a function that handles information and checks for duplicate values, then returns the next number that is not a duplicate. So, I have something like this:
Public Function GetNextNonDuplicateNumber(NumberToCheck as Long) as Long
//the non-duplicate the function will return
Dim NonDuplicate as Long
'duplicate
If CheckForDuplicate(NumberToCheck) = True Then
Throw New DuplicateException()
[Code] .....
As you can see, I want to handle the exception specifically, but I also want to throw it when I'm done because I want to alert other code outside the function. The problem is that simply throwing it exits out of the function with a null value.
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Jun 17, 2010
1) How is ON ERROR GOTO -1 used? I don't understand the help text.
2) ON ERROR seems to be deprecated. What is the recommended Try...Catch replacement for ON ERROR RESUME NEXT. ie. where I have a series of commands, any of which may throw an exception, and I want to ignore all exceptions yet attempt every command?
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Feb 18, 2011
I have written a VB.NET 2.0 code and in my code i am calling class.Showdialog and for that i am getting thread exception. I have mentioned the call stack of the exception. Can any one help me out to resolve this issue. [code]
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Sep 24, 2011
I am catching sql exception from databse as shown below.[code]Now I want to throw exception by adding some userfiendly information,Like below.Throw SQLexception + "my message.....".
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Oct 16, 2009
Assume you have the following code:
Instead of doing:
Try
'
[code].....
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Apr 24, 2009
while my first .net steps I want to understand and test the Method
Private Sub MyApplication_UnhandeledException in ApplicationEvents.vb.
But if I throw an exception the IDE stops and says "unhandled exception" and gives solution tips.
Is it possible to switch off those exception warnings and run through the unhandeled exception handling in ApplicationEvents.vb ?
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Feb 9, 2012
I'm not getting any errors, or anything I just forgot how to do error checking in the "set" portion of properties
I have 3 Classes, my frmMain,Sales and a Validator Class
Code for the Validator Class:
CODE:
Code for my Sales Class:
CODE:
I need to Throw an Excepton when the Sales price is Zero or negitive and when the trade in allowance is negtive I'm not quite sure how to do that in the Object Oriented Manner.
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Nov 18, 2011
If I have an existing exception object (I'm not in a catch block, I just happen to have been given an exception object), is there any way (re)throw it while preserving it's stack trace?
The context for asking is that I'm writing a RunWorkerCompleted handler. If an error happened while running the background task, then this will have shown up in the Error property of the RunWorkerCompletedEventArgs. To keep the code simple I want to use the same error handling code to trap this, or any error that happens later during the handler. That means I need code like this:
Private Sub OnDone(ByVal sender As Object, ByVal e As RunWorkerCompletedEventArgs)
[Code]...
I don't think that using an InnerException here (ie. saying something like Throw new Exception(ex)) will work because then I have the problem that my Catch block has no way of knowing whether the exception it's supposed to be handling is the outer one or an inner one. StackOverflow seems to have various similar questions, but I've not found anything that describes this particular situation.
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Oct 29, 2009
When I print to the printer, using the PrintDocument, I want it to be able to throw an exception if there is a problem. Currently, if I print to a printer that has a jam, is offline, or doesn't even exist, VB still thinks it printed fine. I never get an error. How can I have the printer report back to my program so that if I print to a printer that doesn't even exist, it wont let me do it? I just tried adding a LPT1 printer to my computer (and there is no local printer). I called it some random printer and installed some random driver. Then used my program to print to that printer and never got an error.
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Mar 12, 2009
I want to throw error, if i used methods from this namespace System.IO
For example,
If i write File.Delete("TempPath") , i have to throw undefined Method..
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Feb 15, 2012
Having problems with null dates in a mysql table. Have eventually found out that I can store a 'null' date in mysql as "0000-00-00" and I can run the 'insert' command to add a record to the mysql table. When I check on mysql workbench I can see the row has been inserted correctly and the date shows as "0000-00-00".However...When I try to load the table into a datagridview, I get an error = mysql Conversion Exception was unhandled = "Unable to convert MySQL date/time value to System.DateTime".
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Jul 9, 2010
I Have just been watching a video on throwing Exceptions. Are you supposed to throw System.Exceptions from within your custom classes. to the calling code, Which other way can they communicate. I have read in several places it is bad practice to throw SystemExeptions.
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Jun 19, 2012
i have about 20 possible exception messages that i want thrown when an error occurs.i need somthng like this when catching the exception
Try
' do domthing
Catch ex As CustomInvalidArgumentException
'do domthing
[code]....
do i have to create a class that inherits from Exception for each type of exception?
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Dec 26, 2009
Is there anyway to create a Custom Exception without inheriting System.Exception?
my reason is that they have a lot of methods which i do not wish my Class to have.
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May 30, 2011
I have below program that throw exception. Do you know how to fix??
Dim conn As New SqlCeConnection
conn.ConnectionString = "Data Source=" & Dir & StockTakeFile & ";Persist Security Info=False"
conn.Open()
Dim cmd As New SqlCeCommand("select * from TableStockTake", conn)
Dim reader As SqlCeDataReader
reader = cmd.ExecuteReader()
[Code]...
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Jun 2, 2009
If I throw an exception from within a catch, does the finally (from the catch) still execute? i.e.
Try
..some code with an exception in it...
catch ex as Exception
throw new SpecialException("blah blah" & ex.Message, ex)
[code]....
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Dec 9, 2011
in VB.NET i have 2 custom controls, one is a TextBox and second one is a ComboBox.These have custom values like Bool _IsHidden and are added on runtime to a form.Now, at some point in the code I want to check if the _IsHidden is set to True or False and display that information. Since the user can edit this values when creating the control these are not set on creation.
So what I tried is:(all of this is on MDI Forms)
For Each frm as CustomForm in Main.MdiChildren If frm.MyName = calledBy Then 'this part is just to know which form called the form to create the object For Each cntrl as CustomTextBox in frm.Controls'DO Something
Next End if Next
Now.. if the first control is a custom ComboBox it thorws an error since it sees that it does not match the custom TextBox control..how do i get around this? By my understanding it should just go through all of the controls on the said form and just check those who match CustomTextBox control ?
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Jul 31, 2009
I am trying to learn .NET This is what I found on MSDN. I can create an exception class by using this code.
PHP 'Exception Class Code
Imports System
<Serializable()> _
Public Class copyException
[Code]...
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Jul 27, 2009
For some reason one of my controls produces the following excecption error when adding to the VS ToolBox:Request for the permission of type System.Security.Permissions.SecurityPermissions, mscorlib, Verion=2.0.0.0, Culture=neutral etcWe have identified it is this class within the Custom Control but we not sure whyit is erroring
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Jan 16, 2010
Is the only way to create custom exceptions to inherit from System.Exception?
I wish to create a class that can be thrown as an exception but i do not wish to inherit from System.Exception because i have a base [Object] class in my library which all my classes should inherit from and i wish my custom exception class could also inherit from it.
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Feb 25, 2009
I wrote a class which imports System.Collections.ObjectModel. For the management of the collection, I've written:
Default Public ReadOnly Property Item(ByVal vntIndexKey As Integer) As ItemType
Get
Return CType(mCol.Item(vntIndexKey), ItemType)
[code].....
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Oct 6, 2010
Let's say a custom exception is thrown in the DoWork event for a backgroundworker. How do I pass the custom exception to the backgroundworker so that it ends up being the e.Error in the RunWorkedCompletedEventArgs?
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Jan 18, 2011
i have a data set on the data set many data adapters .i add a data adapter in the data set the designer was automatically delete then lot of error was coming and i search in google and i go this method and i do that right click the data set and "Run Custom tool" on that time the designer will automatically created. but when i do that a error was coming "The custom tool 'MSDataSetGenerator' failed. Exception of type 'System.Data.Design.InternalException' was thrown."
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May 13, 2012
This may be a debugger issue, but here goes:I have this piece of code:
Private Function Connect() As Boolean
Try
sessionBegun = False[code].....
My intention is to 'convert' the low level exception into something more meaningful, so I throw an exception of my own creation. I want this to bubble up to a place where I can handle it.However what is happening is my debugger breaks and tells me that an exception of type "QuickBooksConnectionException" was thrown.I know that, I just threw it, why are you catching it? From what I've read, this ought to work, and there doesn't appear to be an analogous Java throws keyword, so perhaps it is my debugger.
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