I wanted to define a property which accepts decimal numbers and do some process on the value and return string such as the below:
Public Property Amount() As String
Get
Return Utility.PaddingRight(Me.msAmount.ToString(), 10)
End Get
[code]....
But compilers warns "Set parameters must have the same type of the containing property."It doesn't look like it should throws an error since it looks legit.
In VB.NET, if I create a class it is a reference-type. But, if that class it chock full of value type properties, how is this handled? If the class is instantied but never filled, I suspect a pointed for to the heap is allocated. But is more space allocated on the stack for all of it's value type properties?
View 4 RepliesI have a list(of object) lets say ob1,ob2,ob3 that are classes I want to write a linq-querry that exstract from this list only one particolur object that is different time to time how can I write the linq querry?
dim List as new list(of Object)
list.add(ob1)
list.add(ob2)
list.add(ob3)
dim Result=(from P as ob3.gettype in list select p).tolist
but it does not work?
I'm using the Hashtable class for the first time, and have a question about it:Is it possible to define a type for all it's elements? So that when you for example only put strings in it, you can retrieve them without having to cast them from objects.
View 7 RepliesI'm trying to recreated some Excel code and an struggling with defining data types for use in Arrays.
Excel Code
Type Bags
feed_Bags As Long
drop_Bags As Long
level3_Bags As Long
mcs_Bags As Long
[code]....
How can I re-created this in VBA
Im trying to grasp session varibles, i understand what they are etc but i would like to know how to define a type for each session variable.Iv written it like this
Session("Title") = txtTitleContent.Text
How can i tell it what type of value is going to be in it, because at the moment im only playing about with strings, but what if i have an integer and want to pass it back to the back end to save it will throw an error saying "conversion from string to integer is not valid" should i use Cint to deal with this?
I'd like to create a user-defined data type in VB.NET but don't know how to do it.Take an example.......say there's a variable to control the action of a timer control. The possible actions would be "no action", "run timer", and "stop timer."I could do this with an integer (e.g. 0=no action, 1=run timer, 2=stop timer), but I'd rather create a data type so that the options are more explanatory than a simple integer. Like so....
Private Timer_Action as MyDataType
Timer_Action=MyDataType.RunTimer
[code].....
I am trying to figure out how to get at an anonymous typed object's properties, when that anonymous type isn't created in the current function.
Specifically, I am binding an ASP.NET ListView to LINQ resultset, then trying to process each item in the ItemDataBound event.
Option Explicit On
Option Strict On
Class MyPageClass
[Code]....
How can I get all the properties of a class that implement a specific base class or interface? I have a properties class that contains several other property classes. Some, not all, of these classes implement an interface. I would like to know if it's possible to iterate over all properties of parent class for child-classes that implement the target interface. It sounds like a job for reflection? I'm just not sure how. Can it be done via the "PropertyInfo" object?
View 1 RepliesIf I have a complex structure which contains properties which are both simple and complex types, how can I iterate over all the properties of this structure and any child properties which are not simple types?
I have a complex type called file, which contains lots of string properties and some which are other complex types which contain similar structures, eventually the whole structure breaks down into strings.
At the moment my code looks like this:
Dim file As New File
Dim props() As PropertyInfo = file.GetType.GetProperties()
_propList = New CheckBoxList
[Code].....
This works, but it is ugly and I am not at all happy with certain chunks, specifically the type comparisons to establish if this is a date, string, decimal or boolean which are the potential low level types which I want to get out.
In C# it would seem these type comparisons are easier, but i seem to have to create an instance of a given type to be able to use GetType to return its type.
I am trying to redirect command line output to a list box in a vba macro, and I've found some code that I think might point me in the right direction, but I keep on getting the same error. When I use this code [code]It gives me the error in the title and highlights the first declaration line.What does it take to define a new "process".
View 1 Repliesi need to do something as the old scholl on vb6, create a control array, i need to put 50 listviews controls and when the form is initialized start asigning properties since i will drag items to each one of those grids, im goin to make a dragdrop event to handle all the 50 controls, dont like the idea of adding handles c1, c2,cn, c50 but whatever, is there soemthing easy to create a routine to change properties and add columns to each one control dinamically?
sample
for x=0 to 50
control(x).property = true or ""
next
How to get Hardware properties in VB Express 2010 like video card name and memory type?
View 2 RepliesI'm learning LINQ and VB and just spent an hour trying to access the fields of an anonymous type defined in a linq query. The key (I learned) is to convert the query to a list before you try to iterate through it with a for loop. How to access property of anonymous type in C#?
This does not work: edit (this compiles, but intellisense does not recognize the type)[code]...
Each time I create a program, if I don't change the CPU type to x86 in the Project Properties, Compile, Advanced Compile options, it doesn't work. For example, if I hit the drop down button on a combo box, there will be no data, but after switching to x86, there is data. How does changing the CPU type affect how others (such as when its being graded) view the program? If the program is not run on an x86 system, would it appear to not work then?
View 1 RepliesI've come from a Assembler and C/C++ background, so I understand the concept behind reference types versus value types in vb.net. Also, I've read Jon Skeet's article regarding references and value types and I understand all of that. My question is: How can you tell if a given type is a reference type or a value type? Is it simply that all integral types (ints, floats, etc.) are value types and all classes are reference types? (If so, where do strings fall?)
[Code]...
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>
[Code].....
I'm trying to add a new record to my database but i keep getting the message - "conversion from type DBnull to type string is not valid". I think its something to do with the Employee ID when VB attempts to save it to the database my code is below
Imports System.Data.OleDb
Public Class Add
Private Sub DisplayRow()
[Code]....
I now have SQL Parameters set up and I'm using them to save/delete/add my data. This all works well, except when it's trying to save a combobox to the datatable it appears with the error above.Majority of my comboboxes have datasources, and the valuemembers of these are the actual list items, not the ID's of the list items.I'm not sure why this error could be happening, I'm fairly sure I've connected everything to the binding source correctly; I've checked it a few times.Does anybody know what the cause of this could be? I've looked around a bit and I haven't found much
View 7 RepliesI've spent quite a bit of time reading up on generics, covariance, etc., and I am failing to understand why I get the aforementioned compiler error in this type of codeLet's say I have a base "Bill" class made up of a collection of Lines..
Public Class Bill(Of L As Line)
Private _lines As List(Of L)
Public Property Lines() As List(Of L)
[code].....
E.g. how do I get VB.Net to statically type a local variable to be the static type of the expression on the right had side of the assignment?
View 1 RepliesI 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
[Code]....
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 have a number of controls (Device1, Device2, etc.) that all inherit from BaseDeviceControl. In the DragEnter event handler I am trying to test for the correct type by using the BaseDevvceControl like this....
[Code]....
I'm compiling a VB.Net 2.0 app (created in VS2008) using msbuild, and now I've added a generic return type, it's giving me the following:
Warning: Type library exporter encountered a generic type instance in a signature. Generic code may not be exported to COM.
Having just spent ages removing all of the previous warnings, I don't really want to add a new one. Any idea how to get rid of it (aside from not using generics)?I don't know what details I'd put in the attribute, or what number to put in the project-level ignore list.
I am pulling data from a local MSSQL database using a stored procedure, then send the data to a web service. Every part of the component works well except for a pesky problem will a DBNull being returned from the DataRow field, when I know that the field is not null and has valid data. The database and associated INSERT statements that add to this field are designed to not allow NULL entries. When I debug break the program on or right before the line that throws the error I see that the field has valid data for the current row.If I add a null check to the code (as below) the operation continues as normal:
Dim dataResultsTable = Me.myViewTableAdapter.GetData(int)
For Each myDataRow In dataResultsTable.Rows
If worker.CancellationPending Then
[code]....
Why is the read operation returning DBNull instead of the data in the database?
EDIT: Just to be clear, the operation does return the proper data, but the data is not being saved into the variable.
I declare my dates as the following in my code:
Dim DeliveryDate as Date
But i am now trying to declare time however i keep getting an error because i cannot get the type correct. I tried the following but get the following error: "Conversion from type 'Timespan' to type 'integer' is not valid".
Dim DeliveryTime as DateTime
Dim DeliveryTime as Integer
In my database the DeliveryTime type is set to Time(7) so i would assume there should be 'Time' which i could use to declare it, but there isnt. What is the correct type i should be using?
Here is my exact code. There error is Input string was not in correct format:
GraphDate4 = String.Empty
DeliveryProducts = "{ name: 'DeliveryProducts', data: ["
If DataReader4.HasRows Then
[Code].....
I 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
[code]....