VS 2010 Data Bindings - Invalid Cast Exception With DBNulls
Sep 8, 2011
I'm binding a ComboBox's SelectedIndex to a Nullable database field like so:
VB.NET
ColapsoComboBox.DataBindings.Add("SelectedIndex", EnsaiosBindingSource, "Colapso", False, DataSourceUpdateMode.OnValidation, 0)
As you can see, I've defined the NullValue to be zero, yet I get an InvalidCastException. Is there anything I'm doing wrong? Or is handling the binding's Format and Parse events the only way around this?
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Oct 10, 2011
I've got a masked text box that throws an invalid cast exception if I try to put anything in the TextChanged event:
Private Sub mtbZVal_TextChanged(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MaskInputRejectedEventArgs) Handles mtbZVal.TextChanged
MsgBox("OK!")
End Sub
Even more oddly, it throws the exception in a completely different part of the program. The masked textbox is on a form that opens when you press a button, and that's the bit that gives the error:
Private Sub cmdAddLoc_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles cmdAddLoc.Click
If frmLocation.ShowDialog() = DialogResult.OK Then
End If
End Sub
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Nov 21, 2011
I'm just converting a date to a string but I'm getting this error. It's not listed as one of the normal exceptions to the datetime.tostring method. Googling around, it looks like it's an actual bug where it thinks StartDate is an int--but that's no help to me, as I just need to convert the date.
dim StartDate as nullable(of date)
dim Date1 as string
if not StartDate is nothing then
Date1 = StartDate.tostring("yyyy-mm-dd")
end if
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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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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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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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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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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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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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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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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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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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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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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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Feb 9, 2012
Private
Sub cmdExit_Click(ByVal
sender As System.Object,
ByVal e
[code]....
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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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Aug 7, 2009
why do i get an error here?TextBox1.Text = TextBox1.Text & Str(ColorDialog1.Color)
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Apr 27, 2010
I get an Invalid Cast Exception - Conversion from string to double not allowed. I don't know what to do.
Option
Strict
On[code]......
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Nov 2, 2009
I've created a class that inherits from Dictionary(Of TKey, TValue) called KeyCopyDictionary(Of TKey, TValue). I'm now trying to use a pre-existing function which returns a Dictionary(Of String, String) and assigning it to a variable of type KeyCopyDictionary(Of String, String). I'm getting an invalid cast exception. Is it not possible to assign a variable of a parent type to a variable of its child type? I've tried DirectCast and CType to no avail on this...
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Jan 13, 2011
I am using VB.NET 2010 (Visual Basic 2010 Express) on a WPF-based project. I am also using the SQL Server Express built-in to Visual Basic 2010 express.I have just about finished refining my code for hooking up my wpf-based form to an existing SQL database (agentroster.sdf). I have a global data source (AGENT_ROSTER) connected to this database. Connections are confirmed to work properly.This is the first part of the code I'm using, irrelevant code omitted,
Dim table_adaptor As New AGENT_ROSTERTableAdaptors.AGENT_ROSTERTableAdaptor
Dim roster_table As New DataTable("roster_table")
Dim rowposition As Integer
[code]....
how do I fill roster_table with table_adaptor (or alternate method)?
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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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Nov 28, 2009
I have the following code and I'm getting tons of Invalid cast Execptions This is for VB 2008 Case Study Auto Center ( Car Wash)
Imports System Imports System.Drawing Public Class frmMain
[Code]...
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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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Aug 12, 2010
I'm trying to make a card game where the user chooses either Clubs, Hearts, Spades, Diamonds or Joker and then the computer randomly chooses a card to counter and then depending on the formula of what beats what the scores are tallied.
Here is the:
Public Class Form1
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
[CODE]...
Now I pick a card and the computer picks a card and it displays the winner but then immediately it sends me to the coding highlighting lblcomp.text += Val(0.5,1, or 4) saying "Invalid Cast Exception was Unhandled" "Conversion from string "" to type 'Double' is not valid.
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Feb 18, 2011
Moved from Microsoft Developer Network
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Windows Debugging
[Code].....
MS has a patch for the OnListChanged event handler issue, even though it seems we have to pay to have access to it. This fix specifically addresses an error message when you press ESC to cancel adding a new row in .NET 2.0: [URL]
FIX: Error message when you try to press ESC to cancel adding a new row to a DataGridView control in the .NET Framework 2.0: "An unhandled exception of type 'System.InvalidOperationException' occurred in System.Windows.Forms.dll"
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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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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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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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Sep 10, 2011
I'm trying to make a program that will analyze two textboxes and highlight any words that don't match. Here's an example:
[Code]...
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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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