I'm trying to re-write an old VB 6 OCX into a VB.net DLL and I'm having problems accessing the object returned from a COM object. Here is a snippet of the old VB 6 code: Dim objResult as Object
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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.
I have user control which has one button. To handle click event of button I have added following code in usercontrol.
Public
Sub ChangeClickHandler(ByVal
[Delegate] As EventHandler)
[code]....
Now, I want to handle this click event where I call the this usercontrol. I call the usercontrol through reflection so I get the control in a form of object.
Dim button as object button.ChangeClickHandler(AddressOf mymethod), this line gives me error "'AddressOf' expression cannot be converted to 'Object' because 'Object' is not a delegate type."
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.
i've created bunch of classes. i have webservices which reference these classes and contains the classes as parameters and return objects.when i call the weservice, i have to convert the class to the webservice object else i can type conversion error.is there a generic way to convert between these types without having to assign the values by hand?
for example
public class person
fname as string
lname as string
end class
[code]....
i would liek ot be able to call the web service and return the data type back and have a generic coversion instead of as above in stead of:
dim wsPerson as wsReference.Person = ws.getperson()
For I = 0 To 10
If Items.Count = 0 Then Exit For
Dim T As New Thread(AddressOf Thread)
T.Start(New Object() {"Test", "Test"})
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When I put same code in empty project it works.
Occasionally I encountered this exception message while trying to download file from a server using System.Net.FtpWebRequest and System.Net.FtpWebResponse Object.
Download a file.ftpRequest_DL.Method = WebRequestMethods.Ftp.DownloadFile get the response object
Dim ftpResponse_DL As FtpWebResponse = CType(ftpRequest_DL.GetResponse, FtpWebResponse)
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I was create Access database with Access 2003. I create VB project with Visual Studio 2005 Standard With connection wizzard I create coonect with this Access database, select all tablesI see this database inside Data sources and inside Server explorer Test connection is OK When I drag and drop table from Data sources, Wizzard don't create DataGridView, DataSourceBinding etc .. and I see popup window with mesage: Object reference not set to an instance of an object and then "game over"
View 2 RepliesI have a solution with several Projects in it. There is a Windows App project (called ImportClient), and a Class Library (Import.Library). The Import.Library has functions to perform data imports (I have other applications in the solution that also need to call it). But the interactive application, I want to be able to pass in some form controls, and have it update the GUI. No problem. But, I also want to execute a DoEvents() so that the loop execution doesn't hang other interaction to the app.
So, ImportClient has a reference to Import.Library. But I can't add a reference to ImportClient to the Import.Library, because the compiler complains about circular reference, etc. I don't know how else to define the My.Application object of ImportClient as a parameter to the data function in ImportLibrary.
(I realize this is a dumb question - problem is, for this project I have a tight timeline, and haven't learned how to do the BackgroundWorker process. If you think I could pick it up quickly, I'm open to some hints about how to update the progress bar on the GUI, and how to pause / cancel the background task.)
I've got a piece of code in a project (MyProject) that contains early bound object from a referenced assembly (We'll call it CommonAssembly):
Dim myObject As CommonAssembly.MyEarlyBoundType
now I have another assembly that is dynamically loaded because it is not present in all projects:
Dim myLateBoundObject As Object = AppDomain.CurrentDomain.CreateInstanceAndUnwrap("Utils", "Utils.MyLateBoundType")
MyLateBoundType derives from CommonAssembly.MyEarlyBoundType, and I want to cast myObject to myLateBoundObject and then programmatically invoke the additional
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i always get this error when i tried to update my table: Unable to cast object of type 'System.Object[]' to type 'System.String[]'.
i only want to update STATUS, ENDTIME, and PRICE
the data type of each field are:
STATUS = nvarchar
ENDTIME = smalldatetime
PRICE = money
[Code]....
This should be a fairly common question, but I haven't found a straightforward answer anywhere.
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object
Dim ret_obj As New big_obj(<lots of stuff>)
Return ret_obj
End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
I am tightening up my coding with the Option Strict set to ON. It has now produced alot of errors. An example of this is:
If AllocatedDGV.Rows(i).Cells("RoomNumber").Value = RoomsAvailableDGV.Rows(j).Cells("RoomName").Value Then
It gives me the following error: Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity.
i created a DatagridViewNumericUpDownColumn but i got error message Cannot access a disposed object. Object name: 'NumericUpDown' when i closed and reopen the form. what can i do to solve this problems? i checked from the web & i found the answer, but i I couldn't get authorized to view this thread. When i clicked on the link[URL]..It shown You are not authorized to perform this action.
View 3 RepliesI need to write an interface to get data to/from our data files.
We have a low level class that holds field values for each record read from the files.
This just holds two values, the value read from the file (DBValue) and the updated value that may need to be written back to the file (CurrentValue).
These values may be any of the standard value types (integer, date etc) or a string.
Either value (DBValue or CurrentValue) may be null if not defined.
I have written the class to manage this data which works fine while option strict is NOT on.
But we have an office policy of having option strict on all the time.
When I put option strict on, my object value comparisons fail with the error: "Option Strict On disallows operands of type Object for operator '='. Use the 'Is' operator to test for object identity."
Question, how should I change the following code to handle option strict on ...
This is all running on Visual Studio 2010
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I have a class named State that stores a lot of data regarding the current state (status) of the program (like the user's name, has he saved his work, last color he was using, etc). Before I allow the user to reset the state of the program, I want to backup the entire contents of State in case the user changes his mind and wants to undo things back to the way they were. I'm not looking for a complete undo algorithm, just a way to copy the contents of one object to another object (of the same class).
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I am currently writing unit tests for an application near completion (before management looks at it and turns it inside out). I am testing the business layer and a method is set to return a datatable of all "GroupID"s, which are simply an integer to represent the group that a user belongs to.
I'm assuming the best way to assert on this unit test would be to assert that the correct groupIDs are being returned from a controlled test database. However, I'm not sure how to assert on a datatable. Is the only (and best) possible way to accomplish this to simply loop through the datatable until it's empty and add each value to an array of integers? How would one go about asserting on this test?
If I instantiate an object within a function in VB.NET and return it, does it return it be reference or by value. IE - should I be worried about performance if I write something like this:
Public Function ret_obj_func() As big_object
Dim ret_obj As New big_obj(<lots of stuff>)
Return ret_obj
End Function
If I call this function from somewhere else, will it instantiate the object in the ret_obj and then create a deep copy to pass back a copy to the caller, Or will it just pass back a reference?
I run VS 2010 Premiuim version. I do a lot of data projects and wondered what option i have to setup concurrency if the returned object is a dataset and how do i do it? Does VS 2010 have any built in options for me to take advantage of?Or if anyone else has any other ways of doing this please advise or point me to any articles.
View 4 RepliesI am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
If I created a new instance of an object, is it possible to call that object's functions without knowing the name of that object that I initialized it to? Perhaps there is another way to access this object without using the name?Also, is it possible to create a property in a class which allows you to use that property to access an object of that class?For example, a textbox control has a (Name) property which allows you to use that name to access the textbox but that might be a special case because it is a textbox.
View 1 RepliesTrying to replace Cells(RowIndex,ColumnIndex).Value() calls by row-wise references for performance, I permanently fail at referencing the result. Starting with Excel Interop - Efficiency and performance, which contains the tip to use get_range, i.e.
//get values
object[,] objectArray = shtName.get_Range("A1:Z100").Value2;
iFace = Convert.ToInt32(objectArray[1,1]);
//set values
object[,] objectArray = new object[3,1] {{"A"}{"B"}{"C"}};
rngName.Value2 = objectArray;
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However, referencing Values with two dimension indices always returns an "index was outside the bounds of the array" exception. Inspecting the array with the debugger shows a nice 2-dimensional array which should has 17 elements on the second dimension, so Value (0,0) should indeed be a valid reference -- but it isn't:
The debugger lets me inspect Value, I can also drill down to Value(0,0) and see the correct value, but re-evaluating just that element, i.e. inspecting "Value (0,0)" returns above message.
when view in browser, i got this error: Unable to cast object of type 'ASP.webform1_aspx' to type 'System.Web.UI.WebControls.Button'.
how should i solve this problem?
Line 7: If Not Page.IsPostBack Then
Line 8: Dim rowIndex As Integer = 0
<b>Line 9: Dim btn As Button = DirectCast(sender, Button)</b>
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I had write code (just for learning), the codes :
dim Temp as string
Temp = Recordset("
Table_Field")
but, when I start Debugging the error messages "Unable to cast object of type 'ADODB.InternalField' to type 'System.String"
I am implementing IMAPI2 into my vb.net project but ran into a wall. I am getting the message Unable to cast object of type 'IMAPI2FS.FsiStreamClass' to type 'IMAPI2.IStream' when trying to start the burn. I googled around and found this is something that microsoft hasn't fixed.. which basically renders IMAPI2 useless in vb.net.
I found a post on codeproject.com by eric hadden who combined the IMAPI2.dll and IMAPI2fs.dll into an c# interop file. I also see the IBURN interop in microsoft SDK samples. I'd like to use either, but it's in c# and I'm using vb express. Does anyone know a way to get the interop into visual basic or a way around "Unable to cast object of type 'IMAPI2FS.FsiStreamClass' to type 'IMAPI2.IStream'"?
I'm having a problem with converting from one source type to a destination type. I have a form with 2 buttons (button 2 uses the OpenFileDialog to have the user open an excel file set to NewFile),(button 1 takes the contents from specific cells in NewFile and arranges them how I need into oXLApp1).
The error I get is "Unable to cast object of type 'System.IO.FileStream' to type 'Excel.Application'." in line 14 of the code below.
Public Class Form1
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
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I'm new to VB 2005, the code below is actualy coded from VB 6 and just converted it to VB 2005. I'm having trouble with line that's on bold letters.In VB 6 this works just ok. By the way the error message is "Unable to cast object of type 'System.String' to type 'ADODB.Connection'." [code]
View 5 RepliesI can't cast my objects. I get: "Unable to cast object of type 'ClassA' to type 'ClassB'".
The service Class:
Public Class svc_Insp
Implements Isvc_Insp
Public Function Test(ByVal pm_income As ClassC) As String Implements Isvc_Insp.Test
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Unable to cast COM object of type 'System.__ComObject' to class type 'rjsDocMan.Folder'.Instances of types that represent COM components cannot be cast to types that do not represent COM components; however they can be cast to interfaces as long as the underlying COM component supports QueryInterface calls for the IID of the interface.The code where it is flagging the error is:
<div style="color: Black; background-color: White;">
treeview += AddChildren(Session("DocMan").RootFolder)
</div>
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I saw this thread and I had simple answer in mind. To use custom enumerator class. So I was trying to make one for that guy, which would have one more property to check whether its has reached end or not. It would also provide current position.I'm getting an error "Unable to cast object of type 'SZArrayEnumerator' to type 'WindowsApplication1.myEnumerator'." at the line 6 [see below].However, return type of values.getEnumerator says its IEnumerator. [code]
View 14 Replies