Use the "new" keyword to create an object instance & Check to determine if the object is null before calling the method. I'm reading text from a text file using the following [Code]
View 9 RepliesI keep having error message at
ArrayGroup(count).dateDate = valueListString(0),
Code:
Structure dataAttribute
Dim dateDate As Date
Dim timeString As String
Dim volString As String
Dim openString As String
[Code] .....
when i compile my code i got "use the new keyword to create an object instance" at this line " accounts1(sd).Name = textBoxUser.Text"
My code is below.
Private Sub buttonSave_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles buttonSave.Click
If comboBoxAccounts.SelectedIndex >= 0 Then
[Code]....
Private Sub textadd(ByVal sender as Object, ByVal e as System.Windows.Controls.TextChangedEventArgs)
txtfirstname.Text = txtdisplayname.Text
'TODO: Add event handler implementation here.
End Sub
VB is telling me to use the "NEW" keyword to create an object instance. For example: Private Sub ScoreTotal(ByVal sender..., ByVal e As System.EventArgs) Handles ListBox1.SelectedIndexChanged
[Code]....
When I run the "MainStudentScores" form and click on a student with three scores separated by the "|", it should give me a Score Total, Score Count, and Average. However it is giving me an error message at "Scores.Add(intPlaceHolder)" This is where VB is telling me to use the "NEW" keyword. Does this make sense?
I have some code which gets child items for a menu via the GetChildren function which takes a list of menuData: Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
If menuData.Children IsNot Nothing Then
menuData.Children.AddRange(GetChildren(menuData))
End If
Next
If I check if menudata.children isnot nothing, it always is nothing because the GetChildren function is yet to run (providing the child items, which do exist). If I remove this check and just have this code:
Dim builtMenu As New List(Of MenuData)(_rawData.FindAll(Function(item) item.GroupingID = 0))
For Each menuData As MenuData In builtMenu
menuData.Children.AddRange(GetChildren(menuData))
Next
Then I am presented with a Object reference not set to an instance of an object error on menuData.Children.AddRange(GetChildren(menuData))
VB is telling me to use the "NEW" keyword to create an object instance on the highlighted line in the code below, when I click on the button to add a row to the datagrid. Here's my
[Code]...
Currently working on the status bar for application. I would like the status bar to display message errors if a user makes an invalid entry. I have a module which contains the main procedure and procedures to change the text property of my status bar. A Call is made to the procedures from one of the forms that requires the user input. The application compliles but I get an unhandled exception of type 'System.Null ReferenceException' Object reference not set to an instance of an object. [Code]
View 4 RepliesI call the function GetDataTable and when it gets to the return line, I get the error message: Object reference not set to an instance of an object.
Dim DB As New DBConn
Dim gd As New DataAccess.GetData
Dim DT As New DataTable
[Code].....
Updated. I'll see if I can update with the DataAccess.GetData code. I didn't originally put it in there because our shop use it all the time and have no issues with it.
Is it possible to prohibit an instance of a class from calling a shared/static method?
For example:
I want to allow this:
ClassName.MethodOne()
But I want to disallow this:
Dim A As New ClassName
A.MethodOne()
The reason this is desirable is that in this case it is semantically confusing if an instance can call the method.
I'm trying to search a generic list of 'User' business objects which has a property called 'Username': If (From u In colUsers Select u.Username Where Username.Equals(strUsername)).Count > 0 ThenI keep getting:Delegate to an instance method cannot have null 'this'.
View 16 RepliesCalling method in anonymous object?This works:
Call (New MyForm).Show
in vb I can do that
sub SetFocusControl(byref ctl as object)
ctl.Focus
end sub
in c# the compiler complaint that object doesn't have a Focus method
void SetFocusControl(ref object ctl)
{
ctl.Focus();
}
how can I do the same in c#?
I'm not entirely sure what to call what C# does, so I haven't had any luck searching for the VB.Net equivalent syntax (if it exists, which I suspect it probably doesn't).
In c#, you can do this:
public void DoSomething() {
new MyHelper().DoIt(); // works just fine
}
But as far as I can tell, in VB.Net, you must assign the helper object to a local variable or you just get a syntax error:
Public Sub DoSomething()
New MyHelper().DoIt() ' won't compile
End Sub
Just one of those curiosity things I run into from day to day working on mixed language projects - often there is a VB.Net equivalent which uses less than obvious syntax. Anyone?
Is there any sense to set custom object to null(Nothing in VB.NET) in the Dispose() method?Could this prevent memory leaks or it's useless?!Let's consider two examples:
public class Foo : IDisposable
{
private Bar bar; // standard custom .NET object
public Foo(Bar bar) {
[code]....
Can I make an Extension method for all the subclasses of System.Object (everything)?
Example:
<Extension>
Public Function MyExtension(value As Object) As Object
Return value
End Function
The above functions won't work for object instance:UPDATE The problem seems to occur only in VB, where members of object are looked-up by reflection (late-bound).UPDATE AFTER ANSWERED.FYI, as vb has an advantage that C# lacks that is, members of imported Modules are imported to the global scope so you can still use this functions without their wrapper:Dim myObj2 = MyExtension(myObj1)
Basically, I've got this plugin-based application I've used all the time in VS2008 flawlessly. In my current project (VS2010 by the way) I wrote a plugin for the application and whenever I try to use an instance of a particular class (in an external dll) from my plugin, I get an error.
I tried watching the instance and I got the message:
"Cannot find the method on the object instance."
in the watch window. This has never happened before! I also found that some of the extension methods in the plugin does not work.
[Edit] See this post as to why I'm declaring form elements globally. I chose to rewire my code to get rid of the global definitions. [End Edit] I'm creating a from dynamically at runtime. the form, all buttons, and the combobox are all declared globally to the parent form. dim myForm as new form
[Code]...
I just want to check and see if this object is null. if i do not and it is my applications closes.I have also looked into a null reference exception. I will do whatever as long as it handles "null".[code]
View 2 RepliesI 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 class library that contains a number of classes. I would like to dynamically create an instance of one of these classes, set its properties, and call a method.
Example:
Public Interface IExample
Sub DoSomething()
End Interface
Public Class ExampleClass
[Code].....
I'm working through a book that does not provide a lot of example code and what it does provide is in C#. The book refs vs 2005 but I'm using vs2008. The author asks for the user to create a solution with two projects, one winforms and the other a class library (called DependentAssm). The class library is added as a reference to the winforms project In the class library, he asks one to create a new class called SayHelloComp. The project created a file called class1.vb, and a class called class1 which I renamed to SayHelloComp. I left the file name alone, that's ok right?
View 4 RepliesI have a class and method exposed to a client asp.net app. The class looks like
<DataContract()> _
Public Class Class1
Private v_string As String
Private v_integer As Integer
[code]....
The method is declared as
<OperationContract()> _
Function GetStuff(ByVal bar As Class1) As String
In the client code I create an instance of Class1 and set the values for v_string and v_integer, but using Wireshark to look at the xml being sent to the server only a value for v_string is being sent as part of Class1. I'm guessing this is because it considers the value of v_integer to be null/not set. Here is an example of the client code.
Dim MyService as New Service1.ServiceClient
Dim test as New Service1.Class1
test.P_integer = 1
[code]....
how different types are passed/used since Integer is a intergral type and String is a class, but can't seem to work out what to do to fix the problem.
I want to create a class is it where I can do...
[code]...
How do I do this? Do i create a class and create a instance of CarData? but how do I add Color and Year etc to it?
I'm using FileHelper to generate object's property. Here is an example of one property:
<FieldOptional(), _
FieldTrim(TrimMode.Both)> _
<FieldNullValue(GetType(String), " ")> _
Public StoreNo As String
As you can see the StoreNo will either have a value or " ", one of the business policy is to check if the StoreNo is empty or nothing if the object's StoreNo is empty or null then the record will not create.
I though about creating an HasValue Function in the class to check the StoreNo and other properties in the object but I feel like it is a hack.
Public Function HasValue() As Boolean
Dim _HasValue As Boolean = True
If StringHelper.IsNullOrBlank(Me.StoreNo) Then
[Code]....
I don't think this approach is an ideal solution. what if the StoreNo is remove or change to something else. What's the best approach to check object's property?
I am having trouble with this piece of code. This is an event when a check box is clicked. It gives me an error "Object Reference Not Set To a Instance Of An Object"I am gathering that something here needs to be AS NEW something but I have tried a few things and can not get it straight.
If Me.ckbDefault.Checked = True Then
Dim current_indexno As Integer
current_indexno = Nothing[code]....
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"
View 1 Repliesif i create an instance of an object/webpage, is that a complete new object/page based on the original or does it does it just make it accessible? i am almost sure that it creates a new object/page but i would like confirmation. in other words what is the result of this code?
dim Page2 as new Page1
dim Page3 as new Page1
would this create 2 new pages that i can "customize" separately and add different controls to each? heres a brief description of what i want to happen:the user will be viewing Page1 and when he clicks btnCreate i want a page that i created in the designer to be shown and its name and other variables to be determined by what the user chose for room options in Page1. i need "new versions" of this page to be created because multiple users will be creating multiple rooms. i understand that there are more lines of code involved in creating pages and i do have more questions regarding those but i will wait until i confirm that dim Page2 as new Page1 will create a new page. like i said im sure that this does create a new page but i need confirmation. also if it does create a new page, how do i get it to show. i know that response.redirect will redirect me to a dif page but i want show this new room on top of the old one.
I am trying to create new variables inside a class after creating its object at runtime. The problem is that I don't know the variable names or the value beforehand so I have to create the new variables at runtime.
[Code]...
This is a more elaborate explanation of my code. If you observe that in the Eval function I have tried to evaluate Fval(abc). Now the object array abc is not declared in the Test class because it existence is not known beforehand. What I want to do is create an object array abc of length 2 and populate it with some values and when Fval(abc) is called then then the value of index 1 should be the return value of Eval fucntion.
I am getting some wierd errors when using the ReportViewer control in Visual Studio 2008. When I try to access the LocalReport property, it displays with this error: "Cannot find the method on the object instance.". Also, I am getting invalid cast errors saying I cannot cast from Microsoft.Reporting.Winforms.ReportViewer to Microsoft.Reporting.Winforms.ReportViewer. I am getting this using either CType or DirectCast. This is really frustrating as I can find almost no documentation on this error.
View 1 Replies