.net - Why Have Equals Methods Have All Started Throwing Invalid Cast Exceptions

Mar 5, 2010

Several of my overriden Equals methods have started throwing Invalid Cast Exceptions -

Unable to cast object of type 'System.DBNull' to type Common.ResolveUser'.

This occurs when binding List (of T) (where T is of type ResolveUser in this case) to a combo.

Equals Method:

Public Overrides Function Equals(ByVal obj As Object) As Boolean
Dim i As ResolveUser = CType(obj, ResolveUser)
If i.UniqueResolveID = UniqueResolveID Then Return True

[Code]......

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Forms :: Throwing Exceptions From A DLL

Sep 13, 2011

I have a application in which dll of another project added,

In my dll's I have several exceptions defined, and when specific errors occur

I throw these exceptions with the assumption that the main application will catch and handle them if the DLL does not.

but when any specific error occurs in dll main application cant able to catch it and whole aplication get closed. i have added an snapshot which appears when any error appears in dll

how do i handle the exception raise in dll from main project

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Provide Cast Methods For Cast Operator Overloads In C#?

Jun 3, 2009

I read somewhere that older VB .net (pre VB .NET 2005?) couldn't use overloaded operators in a C# class. Is it true for overloaded cast operators?Either way do you guys think it's a disadvantage for a C# class library not to include them and arithmetic methods as actual methods for other languages, like:

ToDouble
ToFloat
FromDouble
Add

[code]....

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WMI Network, VB 2008 Gets Invalid Function/invalid Cast Type

Jul 15, 2009

I'm using WMI code and VB 2008 to see NIC status. So far the queries are working, but the methods aren't. For example, I'm trying to set a network card to use DHCP, I get invalid function with this code:

Dim classInstance As New ManagementObject("rootCIMV2", "Win32_NetworkAdapterConfiguration.Index='7'", Nothing)
Dim outParams As ManagementBaseObject = classInstance.InvokeMethod("EnableDHCP", Nothing, Nothing)

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Throwing Exceptions For User ? Or Better To Design Custom Error Message Framework?

Nov 10, 2010

I never got into detailed error processing too much when I played in VBA/VB6 a lot. Mostly then, if you ran into a user error (such as some input of theirs failing a validation test of some kind), you popped a MsgBox() with some error information and the critical (or warning) icon, and safely aborted out of the code

In .NET, my reading basically points to exceptions as the end-all in error handling. It looks to me that if you know a spot of code where a user can screw up, you're supposed to catch it with either try...catch blocks (for things like data conversions), or standard if...the...else constructs for other things, and then throw a new exception if needed.

Isn't throwing an exception essentially a forced crash of a program in a sense (granted, you get the option of continuing)? Or are exceptions geared specifically for things like data conversion errors and other "things that shouldn't happen", and resume use of MsgBox() and friends for minor user screwups?

Consider the case of where you have a TextBox that is only supposed to accept numeric data (or heck, just a specific set of characters). Barring some other trick that lets you restrict that field (let's just assume it's freeform, programatically), it would seem a bit of a waste to throw new exceptions everytime they type in an invalid character, or even if the error checking doesn't happen until they press a submit button (like on a webpage). Popping a MsgBox() seems more sane in that case.

So what's the straight dope on exceptions and throwing new ones on user errors? How about if your program also exposes a programmatic framework? Bad usage of one of the programmatic functions definitely seems like new exception territory to me.

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C# - Page Methods Throwing Undefined?

Dec 1, 2010

I am trying to use page methods to call a function and I am getting a "PageMethods is undefinded" error. I have used them before whilst using C# but not VB so I'm wondering if my syntax is wrong as all examples I can find are C#. I am also wondering if it's because my scriptmanager is on the master page?

I've read about this error everywhere but everything I have appears to be correct!

My code:

Part of Master Page

<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" EnablePageMethods="true" >

[Code]....

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MVC2 Extension Methods Throwing Errors In Views?

Nov 21, 2011

I have a project written in MVC2 and VB.NET. I use a lot of htmlhelper extension methods,and I have them all in a public module. They work just fine, and I can compile and run my project. I reference the namespace they are in with this:<%@ Import Namespace="MyProject.WebUI.Extensions" %>So, again, they work great, my project runs and compiles without a hitch.The problem is that each one of these extension methods is shown as an error:

Error 33 'TabbedMenu' is not a member of 'System.Web.Mvc.HtmlHelper(Of Object)'. C:ProjectsMyProjectMyProject.WebUIViewsSharedSite.Master 23 21 MyProject.WebUI

[code]....

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[2008] Cast Bindingsource.current To Datarow Throwing Exception?

Jan 14, 2009

im dr As DataRow = CType(Me.ProductBindingSource.Current, DataRowView).Rowbut I get the error saying:

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C# :: Throwing An Exception For A Invalid Number Of Fields In A Csv Record?

Feb 16, 2012

I am writing a parsing method for a csv record and want to throw an exception if the number of fields in the record do not match the expected length

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Invalid Cast Exception Was Unhandled - Unable To Cast Object Of Type 'System.String' To Type 'System.Windows.Forms.TextBox'

Feb 9, 2012

Private
Sub cmdExit_Click(ByVal
sender As System.Object,
ByVal e

[code]....

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C# - What Exceptions Should Be Thrown For Invalid Or Unexpected Parameters In .NET

Apr 21, 2009

What types of exceptions should be thrown for invalid or unexpected parameters in .NET? When would I choose one instead of another?

Follow-up:

Which exception would you use if you have a function expecting an integer corresponding to a month and you passed in '42'? Would this fall into the "out of range" category even though it's not a collection?

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Random Exceptions: System.IO.IOException: The Handle Is Invalid

Dec 27, 2011

I have a relatively simple VB.NET app. It targets framework 2.0 from Visual Studio 2010. The app works fine most of the time, except that the users sometimes receive the

following exceptions. The error is completely random and somewhat rare. I haven't been able to trap it while in a development environment. It also doesn't appear to be

pointing at my code. My app continues to run if the users ignore the error. How would I trap and handle this error?

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Asp.net - ServiceController.start() And ServiceController.stop() Are Throwing Exceptions?

Feb 22, 2011

The following code is throwing Exception. I don't get what mistake I am making in the code. i think it is of some security rights issue. If so, how can I give the security rights to any user or application to access this windows service programmatically?

Dim sc As New ServiceController
sc.ServiceName = "DataLoad"
If sc.Status = ServiceControllerStatus.Stopped Then

[code]....

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.net - LINQ To SQL Invalid Cast?

Sep 3, 2010

I'm getting an invalid cast exception but I'm not sure why, here is the list of my conversions.

SQL -> VB.NET
char(4) -> String
varchar(50) -> String
tinyint -> Integer
char(1) -> Char
bit -> boolean

[Code]...

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Invalid Cast Exception?

Feb 16, 2011

see from the following function why I would be getting an "Invalid Cast Exception"? More specifically this is the error "Conversion from string "yyyyMMdd" to type 'Integer' is not valid." I am trying to convert a DateTime value from the database to a String with the format "yyyyMMdd" so for example October 22, 1985 would be "19851022".dbReader(fieldName).ToString("yyyyMMdd")Here is the entire function ...

Private Function GetDBReaderDateValue(ByVal dbReader As IDataReader, ByVal fieldName As String) As String
If dbReader(fieldName) Is DBNull.Value Then

[code].....

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Invalid Cast Expression?

May 29, 2012

How do I get rid of invalid cast expression from the Values in the Combobox to fit in the equation in examgrade? I tried to resolve it by looking it up on MSDN, and the like but couldnt figure it out.I tried using Examgrade = ().ToString but that did not work.FYI this is my first real program, I successfully made this once in C# but deleted the source files, so this is Visual Basic and a hell of a lot easier to get this far.The asterisks mark the problem line

Public Class Calculator
Dim quarter3 As Integer
Dim quarter4 As Integer[code].....

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Invalid Cast Exception On Same Type?

Apr 15, 2012

i know this may seam odd but I'm getting an error navigating through a datagrid of an invalid cast. The trouble is it is of the same types!! I working on customising some Sage code and in the form there is a datagrid that is populated by a series of Sage.Accounting.Stock.TraceableSOPAllocationItems (a batched stock item allocated to an SOP).

I want to give the user some further information on each item so they can decide which batch and bin to use. I want to go through each item in the grid and then go find this extra information for it. the trouble is when I go to navigate through, My VB.Net code throws the error.InvalidCastException was unhandled by user code, Unable to cast object of type 'Sage.Accounting.Stock.TraceableSOPAllocationItem' to type 'Sage.Accounting.Stock.TraceableSOPAllocationItem'.

[Code]...

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Invalid Cast While Using Inherited Classes?

Jul 28, 2010

I create an application in both C#.NET and VB.NET

When I inherit a C# class in VB I want to be able to set an instance of the VB class to be equal to that from a C# instance.

public
class
SomeClass

[Code].....

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Multiple Invalid Cast Exception For One Try?

Mar 9, 2010

I need to use two Invalid Cast Exceptions on one try. I need to to appear when txtNight or when txtRate has an invalid value.

Try
decCharges = CDec(txtRate.Text) * CDec(txtNight.Text)
lblCharges.Text = decCharges.ToString("n")

[code]....

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.net Dynamic Loading - Getting Invalid Cast Exception?

Jan 6, 2011

I've seen some other responses about this and they talk about interfaces but I'm pretty sure you can do this with classes and base classes but I can't this to work.[code]....When it tries to convert whatever Activator.CreateInstance(t) returns to the base class of type Behavior I'm getting invalid cast exception. That type should be of CharacterController which is defined as a child of Behavior so why wouldn't it let me cast that?

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Error : Invalid Cast Exception Was Unhandled

Aug 15, 2011

I am getting Invalid Cast Exception was unhandled.Conversion from String 'abc' to type 'Double' is not valid in the following line!

If
((xlBook.Worksheets(2).Cells(iRowIndex, iColumnIndex).Value)) = avFoundKeywordds(iSearchText)
Then

The business intent is that user enters the keyword 'abc' and clicks search button . We have defined different keywords in a xls which has 1600 rows and 16 columns . so when finding abc in any of the cells ,it has to return the value of a column#4 where the name is specified !

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Getting Invalid Cast Exception When I Create Proxy

Feb 24, 2011

I am trying to create the Proxy from the WSDL using wsewsdl2.exe [code]...

But i am getting Invalid cast exeption.Can someone please tell me how to i fix it?

I am using VS.net 2003 with WSE 2.0 V3 and Soap 1.1 installed.

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Invalid Cast Exception (Retrieving Image)?

Mar 12, 2011

i save image into a database correctly and now when it come to retrieving i get an error message when the photograph column is NULL.Is there any way i can check if it is null then i execute different code else it return the image.This is what i am using for now

Dim barrImg() As Byte
Dim cmdSelect As New SqlCommand("select Photograph from Personal where MyID=@ID", connect)

[Code].....

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Invalid Cast Exception Was Unhandled In LINQ To SQL?

Feb 22, 2012

Here's my [code...]

On this line "db.jobs2surveys.DeleteOnSubmit(deleteJob2Survey)" I'm getting the following error.
[code...]

What exactly does this error mean and how can I fix this? I can't find much info on Google.

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Invalid Cast Exception Was Unhandled Warning

Jul 18, 2011

We are trying to implement a logic which we used in vb6 2 years back.User enters a business requirement in text box, we define the keywors in the script and once the button is clicked , it shld luk from the list and display a msgbox of number of keywrods found.

1. Invalid Cast Exception was unhandled error -->Warnings

2.When casting from a number , the value must be a number less than infinity -->Warnings

3.When trying to declare ,variant is not accepting and its converting it into Variant Type. Are these both same?[code]

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Invalid Cast Exception When Assigning A String?

Jan 23, 2011

Dim NSNSRC As String = WebBrowser1.DocumentText

This throws me an error although DocumentText does have a value, I have also tried a .tostring after and it still did not work.

Surrounding Code:

While DocCompleated = False
System.Threading.Thread.Sleep(0)
End While

[Code].....

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VS 2008 - Invalid Cast Exception Was Unhandled

Aug 13, 2009

I have declared two variables as strings strDob and strCurrentDate, Both Variables are for storing dates. StrDob is for storing Date of Birth and second is for Present date. and am executing the following code

If DateValue(strDOB) > DateValue(Date.Today) Then
and getting the error like
Invalid CastException was unhandled
Conversion from string "19/09/1987" to type 'Date' is not valid.

Error in the following code also:
iAge = (CInt(Abs(DateDiff("d", strCurrentDate, strDOB)) / 365))
Invalid CastException was unhandled
Argument 'Date1' cannot be converted to type 'Date'.
Here I need both variables as string itself. because the Dateofbirth is getting from three comboboxes.

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.net - IEnumerable.Equals Seems To Call The Wrong Equals Method

May 23, 2012

I implemented a PagedModel class to wrap around IEnumerable to provide paging data for grids in my MVC app.I used Resharper's auto-generated Equality code telling it to check the data, total rows, page number, and page size fields.[code]I found the call to Equals(other._ModelData, _ModelData) peculiar, as AFAIK, this checks that it is the same object rather than that the contained items are the same. Because my tests were failing anyways, I went ahead and changed it to other._ModelData.Equals(_ModelData) with no success. Then I reflected into it at debug time and found that other._ ModelData.GetType().GetMethod("Equals",{GetType(Object)}).DeclaringType was Object! Obviously, that would result in the failed comparison.I came up with a solution to create a EnumerableEquals method which compares every item in the two enumerables to confirm the are the same, but it seems sloppy. Is there anything I can do to use the normal .Equals method? [code]

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Invalid Cast Exception - Storing Textbox Value In Brackets

Aug 7, 2009

textbox1.text = "6916092, 15195440, 16107657, 1836924, 3758726, 12566463, 7526079, 7405793, 6945974, 241502, 2296476, 5130294, 3102017, 7324121, 14993507"
ColorDialog1.CustomColors = New Integer() {TextBox1.Text}
I am getting an InvalidCastException. How do I insert the value of textbox1.text into those brackets in vb.net?

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Invalid Cast Exception, Storing Colordialog Value In Textbox?

Aug 7, 2009

why do i get an error here?TextBox1.Text = TextBox1.Text & Str(ColorDialog1.Color)

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