Unable To Instantiate Database Object
Jan 24, 2010
I have an application which I am trying out on machines without mysql. The app runs fine on my local host however when I try to use the application on another machine I am getting the following error:
Access denied for user 'root'@'localhost (using password: YES)
Then I get a .net framework error
System.NullReferenceException: Object reference not set to an instance of an object.
I thought I had exported the DB but I was left with a mysql file which I placed in the bin directory.
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Aug 11, 2009
dim myCollection as new Specialized.StringCollection
dim myFoundThings as new ArrayList
dim index as Integer
dim newResultMemberName as String
[code]....
This is part of some code that will run without user interaction once it's spinning away, and I need to create a unique object from some items found in a StringCollection, naming the objects using information found in the strings stored in that StringCollection.
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Dec 13, 2011
If I have a console application containing the class
[Code]...
I'm not a VB.NET guy. Am I correct in assuming I need to instantiate my object first? Why does the VB.NET example differ?
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Jun 11, 2009
I'm trying to decide whether to get a value, call it X, in my class through a read only property or through a function. Normally I'd code it as a property except in this case the GET involves doing a lookup to a sql table. So there's way more overhead than a simple RETURN X. So my question is, when I instantiate a new object from my class, are all the properties calculated at that point, so that the sql lookup will occur too? Or is the property only evaluated when I actually reference it in the calling code.
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Oct 31, 2009
i wanted to do something simple that sort of replicate an object:
public function clone(byval realcopy as object) as object return new Control ' something like this works, however i want to return the type of realcopy, which may not be a control end function so i tried this:
public function clone(byval realcopy as object) as object
return new gettype(realcopy.gettype)
end function
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Jan 20, 2010
I am having some real issues with this one. I have a class which contains two other objects...but I cannot seem to instantiate those sub objects. Here is the code for my class:
Code:
Option Explicit On
Public Class Boot
[code]......
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Sep 27, 2011
i've got a generic class for xml serialization and deserialization.
Public Class clsXMLHandler(Of T)
Public Sub serializeFromObject(ByVal filePath As String, ByVal [object] As T)
Dim creater As New FileStream(filePath, FileMode.Create)
Dim xml As New XmlSerializer([object].GetType)
xml.Serialize(creater, [object])
[Code]...
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Jun 22, 2010
I see a sample code that an object is instantiated within the class definition block. But when I test the folllowing, I got error "Process is terminated due to
[Code]...
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Apr 13, 2011
I am trying to run a backgroundworker to load data from my DAL (which is available in another class). I want to keep the UI available and not have the "locked up" feel while the object is loading.When I create a simple backgroundworker and Sleep the UI stays responsive and my controls can be updated after the sleep. As soon as I replace the sleep with a call to instantiate the object from my DAL, the UI locks up. Is there someway I can instantiate this object using the background worked and keep the UI responsive?
When the situation object is instantiated it could take several seconds for it to load completely, during this time is when the UI is locked up... It does eventually load just fine.
Private WithEvents backWork As New BackgroundWorker()
Dim sit As Situation
Private Sub btnLoad_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles btnLoad.Click
[code]....
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Mar 12, 2010
How can I instantiate an anonymous object while passing the propertynames and values as string?
new With { .SomeProperty = "Value" }
new With { ".SomeProperty" = "Value" }
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Apr 8, 2011
I'm running a program where I call a function which creates a database connection and then runs a stored procedure. I call this function four times from four separate threads. I get an error (Login failed for user 'sa'. The user is not associated with a trusted SQL Server connection.
Exception Source:
.Net SqlClient Data Provider)
when I use multiple threads, but if I have the threads run one after another I have no
[code].....
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Dec 2, 2010
In C# .NET 3.5, is there a way to instantiate an object given its string name? For example, suppose I have a DLL (e.g., MyClass.DLL) which contains type MyClass. Is possible to write something like... Object myClass = SomeMethodToInstantiate("MyClass"); // ? Is it possible to do this in VB .NET 3.5?
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Feb 22, 2012
I have
Public stack() As CTest
I want
Public stack() As Object
The latter is giving the error "Unable to cast object of type 'Object' to 'CTest'." when used:
Dim thestack As CTest() = testdatabase.getStack
Where testdatabase.getStack simply returns stack();
Public Function getStack() As Object()
Return stack
End Function
This fixes it, but it's not ideal (for me personally):
Dim thestack As Object() = testdatabase.getStack
So if I could keep the variable as-is (Public stack() As Object) and then do something along the lines of class.stack() = CTest I should be able to do Dim thestack As CTest() = testdatabase.getStack because the object array will programmatically have changed from Object to CTest.
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May 15, 2012
I have a requirement where I need to have a "type safe" way of accessing property names, without actually instantiating an object to get to the property. To give an example, consider a method that takes as arguments a list of IMyObject and a string that represents a property name (a property that exists in IMyObject).
The methods implementation will take the list and access all the objects in the list using the property name passed... for some reason or another, we won't dwell on that!!
Now, I know that you can do this using an instantiated object, something like ...
Dim x as MyObject = nothing
Dim prop As PropertyInfo = PropHelper.GetProperty(Of MyObject)(Function() x.MyProperty)
Where my helper method uses reflection to get the name of the property as a string - there are numerous examples of this flying around on the web!
But I don't want to have to create this pointless object, I just want to do something like MyObject.MyProperty! Reflection allows you to iterate through a types properties and methods without declaring an object of that type... but I want to access a specific property and retrieve the string version of its name without iteration and without declaring an object of that type!
The main point here is that although I am trying to get the property name as a string... this is done at run time... at compile time, I want this to be type safe so if someone changes the property name, the compilation will break.
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Feb 29, 2012
I am attempting to create a new mobile app using VB in visual studio 2008. I select "File" "New Project". Select "Smart Device" in new project window. Select the "Smart Device Project" from templates. Select ".NET Framework 3.5". Select "OK" and get the dreaded "object reference not set to an instance of an object"
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May 7, 2009
This error makes no sense to me[code]...
Unable to cast object of type 'DynamicTreeNode' to type 'DynamicTreeNode'.
I have an inherited TreeView with an inherited class called DynamicTreeNode inside it. I am trying to loop through the DynamicTreeNodes in the TreeView.Nodes property which is causing this error.
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Mar 9, 2012
All I am trying to do is select one school id. Do you know where I went wrong? ty
Public Function findId(ByVal table_name As String, ByVal name As String)
Try
con.ConnectionString = connection_String
[Code]......
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Mar 24, 2011
unable to cast object of type dataset to type datatable.Dim dataTable As DataTable = DirectCast(dataGrid.DataSource, DataTable)
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Jul 24, 2011
Is this code you have obtained from elsewhere? Have you tried debugging it line by line? Which line throws the error?
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Jan 14, 2011
I am new in programming with VS2008. Nowdays I try to built a simulation of graphics movement. I use Panel to draw the graphics but I faced a problem when I want to move the object. There were a message
"Unable to cast object of type 'System.EventArgs' to type 'System.Windows.Forms.PaintEventArgs'.".
Public Class Form1
Dim x, y As Integer
Dim n As Integer
Dim xp, yp As Integer
Dim xt, yt As Integer
[Code] .....
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Oct 7, 2008
i am trying to create an sql parameter but i am having an error. it gives me an error like this: Unable to cast object of type 'System.Boolean' to type 'System.Data.SqlClient.SqlParameter'. on all of this line
Dim paramcollection As New List(Of SqlParameter) ' no error on this part but the lines below gives me an error:
paramcollection.Add(New SqlParameter("@CGLCode", SqlDbType.VarChar).Value =
[Code].....
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Jul 22, 2011
I have do the coding to export the data from DataGridView to Excel. But If am running the code am getting the below error.
[Code]...
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Aug 15, 2011
I seem to have broken something I get this error Unable to cast object of type System.EventArgs' to type 'System.Windows.Forms.KeyPressEventArgs'.
my code:
Private Sub ListControl_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ListControl.SelectedIndexChanged
[code].....
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Dec 16, 2009
I want to do something like this:
Dim selectedCourses As List(Of Guid) =
From item In chkListCourses.Items Where item.Selected =
True Select item.Value
But I get the error:
Unable to cast object of type
'WhereSelectEnumerableIterator2[System.Object,System.Object]'
to type
'System.Collections.Generic.List1[System.Guid]'.
The value of item is a string representation of a Guid. I'd also like the syntax for a Lambda expression.
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Mar 28, 2011
i write this code to work with some radio button and calculate Score for a questionare : Dim SScore AsByte = 0 Dim BTNN AsByte = 0 Dim BTNNS AsString = "" ForEach rBTN AsRadioButtonInMe.Controls If Mid(rBTN.Name, 1, 5) = "RBS01"Then If rBTN.Checked Then SScore = SScore + CType(Mid(rBTN.Name, 7, 1), Byte) EndIf EndIf Next I get this error on line 4 : Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.RadioButton'. i dont know what is it and how can handle it.
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Apr 28, 2009
Unable to cast object of type 'Panel1' to type
[Code]...
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Jul 29, 2011
Why is this query not working
Private mapOverlays As New List(Of GMapOverlay)
Dim mapOverlay = mapOverlays.Where(Function(x) x.Id = overlay.Name).Distinct()
DirectCast(mapOverlay,GMapOverlay).IsVisibile = False
I am getting the error
Unable to cast object of type
'd__7a`1[GMap.NET.WindowsForms.GMapOverlay]' to type
'GMap.NET.WindowsForms.GMapOverlay'.
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Feb 4, 2010
I'm having a real problem with serializing data. I understand that its designed to basically copy the structure and data of a structure. In my case, I have the state of a DVD that i would like to save (persist) to disk. [Code] error: 'Error Generating XML', Inner Exception: "Unable to cast COM object of type 'System.ComObject' to class type 'DirectShowLib.DVDState'.
COM components that enter the CLR and do not support IProvideClassInfo or that do not have any interop assembly registered will be wrapped in the ComObject type. Instances of this type cannot be cast to any other class; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID of the interface."
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Apr 19, 2011
I'm new to generics and am having some issues when using with interfaces.I'm developing with VS2008 - .NET 3.5 Ultimately, I'd like to create an interface that inherits the IList(Of T) interface and add a function definition to the derived interface that adds a new element of type T to the list and returns the index of the newly added item.
I have everything figured out but am stuck on a casting issue. If I execute the following line of code at runtime:CType(New clsObjectFactoryList(Of clsIDNamePair), ifObjectFactoryList(Of ifIDNamePair))
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Jun 1, 2011
I successfully connected a remote MySQL database and it is listed in the Data Connections. My database has two tables, inventory and history, both work and I can retrieve the data from each.The problem is when I try to link the inventory table to a datagridview object. As soon as I enter the configuration wizard a red x appears in my data connections. Regardless of this, however, I can still successfully add my history table. The problem is that the inventory table name isn't visible and I get this error:<``>Could not retrieve schema information for table or view ``.The inventory table is what I need and I don't understand why it blanks out.
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