Suppose a click event is fired and a particular gridview datasource is set in the code behind page by retrieving a data table from a business logic class.
So programmatically speaking, what is the main difference between the two set of code listed below.
CODE:
I guess my main question is, what is the purpose of creating a new instance of an object in the above scenario?
I currently have a control that called MyGridview that inherits Gridview. It has a paging template within it for customized paging options, and I'm at the point where I want to cache the initial datasource for better performance.I haven't done this in a long time, so perhaps there is a different solution these days with the newer frameworks.Before, I simply used a Cache object that was named whatever the gridview was named. I couldn't use the same gridview name through the application though.Is there a best way to have a cache object, or some other object like a session within the control to store those unique datasets for paging and sorting?
View 1 RepliesI have a gridview that I would like to be able to bind to several sqldatasources, but still use template fields. Each datasource is different and would have different columns so I'm not sure how to go about this. Is it possible to define a set of template fields or overlying template per datasource?
View 2 RepliesI have a gridview. Its datasource is set as follows.dtTable is a datable in which the values for the table will be retrieved. But when setting dtTable as datasource I get an error "Object reference not set to an instance of an object". What may be the reason for this?
gridview.Datasource = dtTable
gridview.Databind()
I have a GridView on an ASP.NET page that I'm trying to bind to an object data source that I've set up to map to a vb object I made which accesses the DB. When I run the page, though, the gridview comes up empty.
The ObjectDataSource is definitely returning data. The paging parameters are making it to the underlying object. All the way until I get to the DataBind() call everything seems fine. But the grid comes up empty. Funny thing is, if I use the method that returns all records in the DB, the grid populates just fine. Only when I try to implement custom paging does display no records. I've tried using the wizards, I've tried diagrammatically setting it up and run time. No matter what I do I can't get paged data to display in the grid.
oDatasource = New ObjectDataSource()
oDatasource.EnablePaging = True
oDatasource.TypeName = "tblMessage"
oDatasource.SelectMethod = "GetTblMessageSubset"
[code]....
I am using VB.net.
I have a gridview with a datatable datasource.
What is the best option to update the datatable when i delete a row in the gridview and then show the gridview without that row?
I am stuck at a task. What I want is, I am creating a table in the database on the fly in the code behind using the below code(in VB).Now my main problem is I want to display this table which is created in step 2 of a wizard, in step 3 using a GRIDVIEW. But as we all know a GridView needs a sqldatasource for values to be displayed, however what I need for achieving this is dynamically assign a datasource to the GridView, but I am not figuring out HOW?
Dim NewTable As String
Dim FullName2 As String = "Dynamic" + "_" + lblCompanyName.Text + "_" + tbCustomerFileName.Text
'Get Row Headers and map to Fields
readerXML.ReadHeaders()
[code].....
If I used a generic list Class to hold data objects that I am pulling from SQL Server using Linq to sql to populate a datagridview would I need to make any modifications to the datagridview control to accomodate multiple columns or would I need to make any modifications to the generic list class to accomodate the multiple columns in a row that is typical of a record in SQL Server? And one more thing which I believe is the easy part. To bind the list to a datagrid view would I just use the datasource property of the datagridview control.
View 2 RepliesI have a gridview that is bound to a datasource (Windows Forms, VB.NET). One of columns is a property of type boolean, and I want to show "yes/no" in the column instead of 0/1 or "true/false". Is this possible? Can you edit displays of columns that are bound?
View 1 RepliesI want to created a nested class that can only be visible to and instantiated from the parent class.But I also want to be able to use an instance of the nested class through a public variable of the parent class.I tried making the nested class private, or making the nested class' constructor private, but it won't compile.Is it possible to do this in .NET?
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my proble is the following: I have a class MyClass and another class Modifier, which has a method ModifyMyClass(ByRef mc as MyClass) that receives a MyClass instance as ByRef parameter to modify it. A smell of the code is:
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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
How can i fix this ?
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 you run this code you will see that the 500 PictureBoxes that are added ( this is easier to show than adding pixels as a pixel is only a single point ) fall mainly on the diagonal.With regard the RANDOM class, why should this be like this when the bounds of the instances are? >>
p.Location = New Point(x.Next(0, Me.Width + 1
), y.Next(0, Me.Height + 1 ))
as in this code.>>
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I've createda vb.net class library where I've defined a number of small classes... nothing complicated, just working with strings, sending emails, etc.In another project, I reference the class library and I'm seemingly able to create an instance ofone of tclasses - intellisense shows me all of the plic properties, methods, etc... all looks perfect. No compile errors at all, nothing b gumdropsand lollipops.When I run the app I'm working on that references the class library, it fails at the point where I'm creating an instance of the class and gives me a vague exception, "System.TypeLoadException".
View 2 RepliesIs there a way to define a class such that there can be only a single instance of that class?
View 5 RepliesI need to create a new instance of a class that needs a member of the calling class. But i can't pass a reference to the calling class through the constructor.The solution i am looking for is something like this:
Public Class ChildClass
Public Sub New(args)
_MyMember = GetMemberFromCallingClass()
[code]....
I want this to work without having to manually pass any references or variables from the calling class to the new instance of ChildClass.
I want to create a class that will "search" for something. Basically I load up the "search item" when the class is created and inside the class is logic to do the "search". The result of this logic will be more "searches" that I want to start. How can I have the logic in the class create another instance of the class itself?
View 3 RepliesI wrote an ASPX file in VB.NET. Originally this file ran successfully but after adding one additional parameter it now fails on "Object reference not set to an instance of an object" on line "peType.DataSource = arrPEType" below.This error does not make sense to me though because I have similar parameter, 'dType', which it does not error on. What is the cause of this error?
Here is some of my ASPX code file:
Sub Page_Load(Sender as Object, E as EventArgs)
If Not IsPostback Then
[code].....
Is there a way to get the instance's class name with VB.NET?
View 2 RepliesI have been asked by a code snippet to add the instance of class that contains data i want to add to an XML file, the only trouble is i am not sure what an instance of class is. Is it something that looks like this: [Code]
View 2 RepliesI am working on an ASP.Net 3.5 solution that I did not originally build. I added a class file named Incident.vb to the App_Code folder like I always do.But in my code behind of a web page, I usually create an instance of a class like:
Dim oIncident as New Incident
But after I type "New", normally I would see my class file he intellisense but I do not. So it does not seem to be able to find Incident.vb. I have not seen this behavior before. Trust me, my class is correct. I have created many class files like this.[code]...
I think I just need a push in the right direction. I cannot seem to get my sub from an instance of my class, once instantiated, to run when I click on the button. My Code in the class is
When I click this:Private Sub btnBark_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBark.Click
mydawg.bark()
End Sub
[Code]...
I have a Class, which I create an instance of in order to use, however I have a couple of functions (which don't really relate to the instance data) which I want to use when an instance hasn't been created.
Visual Basic .NET (2010)
Example of what I'm trying to do:
' Log a user into the system (this works)
Dim hedwig As New CustomSecurity
hedwig.Login("username", "password")
[Code].....
this used to be so easy in C++ and VB6 I am dynamically creating multiple instances of a fairly simple class, tracking them via the Collections class in vb.net. I loop through the collection if I need to get to a particular instance to set some property, for example. Everything is fine, and works ok until I try to destroy the instances that I created (largely because I am probably not doing it right). What I am doing setting the instance to "nothing". That is, here is the portion of the code:
[Code]...
I have a class "Character" that holds character stats and skills. I make a new instance of it "MyCharacter". The problem is I would like to use it like this.
MyCharacter.stat.charactername ="whatever"
Where stat is another class within Character or
MyCharacter.skill.lockpick=10, b
But I can't seem to do it.
Lets Say you have a Class
Public Class ExampleClass
Private _Name As String = "Unnamed"
Private _Value As Object = Nothing
[code].....
In a program that I'm putting together, I have a small class and in the program, I add instances of that class to a List(Of [that class]).Later in the program I test whether or not that list contains a particular instance of the class, but it fails to return true when I've proven that it's in there. I've since set up an iteration routine where it finds it, but it has me puzzled why the ".Contains" will not locate it.
My question is simple: When I have a List where I add an instance of a structure or class, does it not actually examine the contents of the structure or class inside it?
how to set string content as a class instance name?Example. I have an INI-class with many instances like .Path, .Width, etc. Now, i'm reading my ini-file string by string wich hase been written by template:
[code...]
I would like to automate reading an assignment at ONCE. Like cutting the first word in line and setup it as my INI-class instance name.I know how to cut first word, but have no idea, how to set this string as instance name.
my aim is to create a new instance box at the push of a button, the box has strings name and Id to be filled concatenating the auto generated ID i.e. 0 to 210 plus a string "Box" added by the user. I had problems earlier creating a structure within the class box, frankly I am not sure if the code below will work, as i try to run it in VB I get an error indicating that I am using the variables strBoxPositions() and strBoxNumbers() without assigning a value to it. The thing is the strBoxPositions() should automatically be filled by arrPosition() which will be created at the same time the new object box is created and the strNumbers() will be created with empty strings to be filled at latter stage by the used as and when necessary.
how could I initialise those arrays to get the program to run and perhaps ill be able to see if the code works or not, or just correct this code with a better way of code with comments, also if possible some indication on how could I update the strNumbers array inputing the strings one at a time on a text box field.
Public class form1
Public Class Box
Public intBoxID As Integer
[Code].....