Having a class that defining ListView in a class, then passing through the methods as an object (listview)
but having error on
Value of type 'System.Windows.Forms.ListView' cannot be converted to 'Proj.MainForm.ReadMsgClass'.
Public Class ReadMsgClass
Public ListView2ReadMsg As ListView
End Class
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I have created a user control in wpf which consists of a textbox and a listview. Now, I want to bind a class object to the list view from the form where I will use this control. So, basically I want to dynamically set the binding for the listview.
View 1 RepliesI 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 am trying to write a class library and I am getting the following error: "Value of type 'WorkMateLib.Login' cannot be converted to '1-dimensional array of WorkMateLib.Login'"
The code of the classes is as follows:
Public Class Logins
Public CurrentUser As Login()
Public Sub New()
[Code]......
I am utilizing a centralized class object that needs to call another class object. The program itself will do something like the following
sFieldValue = CentralObject.ObjectHandler(1, TestFunction, "FunctionVar,FunctionVar2,FunctionVar3")
In the central object I have a function
Public
Function ObjectHandler(ByVal ObjectType
As
Integer,
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I 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?
I have an ActiveX object converted to be functional to WPF (standard procedure: Windows Forms control Library and then embedded into the WPF project using a Windows Forms Host controller). Everything works ok with a simple bug from time to time.I have some things in the Load Event that access the ActiveX controll properties and sometimes I get the error "Exception of type 'System.Windows.Forms.AxHost+InvalidActiveXStateException' was thrown."I guess this happens because the control didn't load before I'm trying to access the properties. That's why I put my properties on a DispatcherTimer with the interval 2 seconds in order to execute them later but I get the same error.
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i have problem LINQ query.In above,i got error system.object cant be converted to Sytem.String. What can be the problem? if i use string() instead of ArrayList, it doesn't raise error. But in String(), i should add items manually [code]
View 3 RepliesI am compressing a dataset converted to XML using the GZipStream class added in 2.0. There are a few things bothering me about this. Here's the code I am using to decompress the XML file:
Using inFile As New System.IO.FileStream(flnm, IO.FileMode.Open, IO.FileAccess.Read, IO.FileShare.Read)
Dim zStrm As New System.IO.Compression.GZipStream(inFile, IO.Compression.CompressionMode.Decompress)
Dim buff(999) As Byte
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This seems inordinately awkward, as I am taking the stream, reading it out into byte buffers, then writing those byte buffers to a memory stream that is then passed to the dataset.ReadXml() method. The reason for this seems to have to do with what is happening in the line colored red. That line is adding a closing > onto the end of the stream. Without that, ReadXml complains about an unclosed dataset. I found out that the > was missing by writing the stream into a string and pasting the string into WordPad. Without that missing >, it appears that I wouldn't need to be using that memory stream at all, and could simply pass in the GZipStream to ReadXML, but as far as I can tell, it's impossible to look at the GZipStream to be sure that the > is not there, and it may be impossible to add it (I haven't tried).
So why is the > missing? Here's the code used to create the file that is being read into the filestream in the above
VB Using ms As New System.IO.FileStream(flnm, IO.FileMode.OpenOrCreate, IO.FileAccess.Write, IO.FileShare.Write)
Dim zStrm As New System.IO.Compression.GZipStream(ms, IO.Compression.CompressionMode.Compress)
ds.WriteXml(zStrm, XmlWriteMode.WriteSchema)
End Using
The real kicker to all of this is that while I was dissecting the first chunk of code, I added a line to check for cnt<1000. My intention was to see the last buffer that was being written into the memory stream to see whether the final > was actually there, or not. To my surprise, I reached the cnt<1000 twice. That means that one read did not read a full 1000 bytes, but read only 675. The next three or four reads were a full 1000 bytes, then the final read was just a few hundred bytes. It is my understanding that Read will return a full buffer if there are that many bytes left to read, and there were, so why did it return only a partial buffer? That suggests that there might be a hole in my XML, though with a half meg file, it's a bit much to read through it looking for something missing. However, the XML that was returned was turned into a dataset that I then merged into some existing data using code that has been working with uncompressed XML files, and I got an error that I should never have received. That may indicate that the XML was, in fact, missing something, though I will have to study the matter further to figure out whether or not that is the case. My major question has to do with the missing '>' at the very end of the file.
I have some ActiveX that was written for VB6. They all seem to return Variant types. Ex.
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In this case the GetPosition control is returning a robot axis position. It looks to me like the values coming back from the function is not getting converted to object type properly.
I'm using the following code to try and search a listview (I got it from msdn):
Dim atem As New ListViewItem = ListView1.FindItemWithText(TextBox2.Text, True, 0, True)
If atem IsNot Nothing Then
ListView1.TopItem = atem
End If
Then I got the " Object reference not set to an instance of an object" error highlighting the following line: ListView1.TopItem = atem So then I tried this:
Dim atem As New ListViewItem atem = ListView1.FindItemWithText(TextBox2.Text, True, 0, True)
If atem IsNot Nothing Then ListView1.TopItem = atem End If it still isn't working.
Here is the structure that I have:
Friend Class StandardFormatFile
Friend fileType As String
Friend numberOfSeries As Integer
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I have some classes, BsfciFile and StudyFlashCard. Bsfci is the extension to which I save my set of flashcards in an INI format. I am currently working to transform my code from using Windows API calls to access the INI to using a IniFile class that I found on the internet. I would like the BsfciFile to have a Array of StudyFlashCard objects, but I would like the StudyFlashCard class to use the IniFile class object contained in the BsfciFile class. I can pass the IniFile from the BsfciFile class to the constructor for the StudyFlashCard class, but I want it to modify the same IniFile as the BsfciFile class has later on.
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I am trying to create an list or an array of a class.Here is my "Ingredient" class that I am trying to create a list of:[code]In my "recipe" class, I am want to create a list (or array) and I am drawing a big blank on how to do it. Can anyone point me in the right direction?
View 2 Repliesdim myCollection as new Specialized.StringCollection
dim myFoundThings as new ArrayList
dim index as Integer
dim newResultMemberName as String
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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.
I'd like to have something like:
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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()
I have a class in which some of the fields are also classes.
I can put values in the "normal" properties, but in the others when o try to assign values it gives the: "Object reference not set to an instance of an object"
But the code compiles fine.
dados_Defenicao = New ServiceReference1.draftClaimEntryDefinition
dados_Defenicao.arCode = "123"
dados_Defenicao.claimMarket.warrantyType = "w" - Here it gives the error
If we are within the derived class then ofcource we can use MyBase keyword to access base class's object reference . That's fine , how can we take that base class's object reference outside that derived class's definition.My following code will explain what i want . Actually that is giving error right now, but it is explaining my requirement .
Public Class Base
Public x As String
End Class
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Actually there is error in ReadOnly Property BaseReference's Getter . Error is "Error 1 'MyBase' must be followed by '.' and an identifier. " how can i get base class object reference in Main method ?
If my namespace is Company.Application.EDI.Acknowledgement and if I stick with theprogramming practice of one class per file then should my class be saved asacknowledgement.vb? Are there any gotchas that will come up?
View 5 RepliesI have a Parent Class Called Fuselage that containsfour child classes called Forebody, CenterBody, AftBody, and CrossSection. CrossSection classcontains objects common to Forebody, CenterBody, and Aftbody (example: width). How do I access thewidth property in CrossSection from within the classForebody?
Public Class Fuselage
Dim Forebody As ClsSection
Dim Centerbody As ClsSection
[code].....
Does link text mean I have to return a concrete implementation? Even though I am using svcutil with the /r that includes my entites(where IMyInterface is defined). I get no errors but it changes all List(of IMyInterface) to list(of Object) and I cannot deserialize it on the client
Error: list(of object) cannot be converted to list(of IMyInterface).
take a look at the following code:
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I am developing an IT Asset Tracking application using VB 2005 and SQL Server 2005 Express edition. Will I need to create classes to represent objects such as Computers, Printers, Scanners/Faxes, Contracts, Purchase Orders etc or are there any other approaches.For example, if I am correct, I will have a class called Computer and its properties will include Make,Model,CPU,Hard Disk,Memory etc. Is this the right approach.
Computers can be split up into Desktop PC's, Servers and Notebooks. Would I have to create separate classes for these as well or would they be ok under the Computer class.Once I create an object from the class, how can I use the object to interact with the SQL db.I am a beginner to VB.NET 2005 therefore I am slowly getting to grips with OOP.
bare with me during this silly example. :-) Let's say I have a class like this:
Public Class Animal
Public iLegs as int32 ' Number of legs
Public bWings as Boolean ' Wings? Yes/No
End Class
And another class that inherits the "Animal" class and adds one more property:
Public Class ScaryAnimal
Inherits Animal
Public iScariness as int32 ' 0-100, how scary is it?
End Class
Now, if I have an instance of "Animal" with some values in it, and I decide I want to cast it to a ScaryAnimal for some reason, how do I do that without having to create a new instance of "ScaryAnimal" and copy each property value?Basically I'm looking for a way to do this, without having to write the lines marked with '*** below:
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If you want a instance of an object to be created when a form loads or another class is created, you have two options:
Public class example
private IAmAObject As IAmAObject
public sub new()
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Or like this:
public class example
private IAmAObject as new IAmAObject
public sub new()
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I always use the first one. It's more type work but I think it's neater. How about you people and is there any real difference between the two?
if I put controls on form1 like button,textbox....etcwhy called this control fields not object in the class diagram ?
View 7 RepliesI am making a listview and I want to display an Object.
View 4 RepliesIn C# i would do something like:
mytype val =
(mytype)mylistview.SelectedItems(0).Tag;
how can I do the same thing in VB.NET?
I'm new with VB.net, also with OOP.
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how I can use the Listview to pass the parameter to the second Forum by using the tag and the full object of vb.net.