Now C# 4.0 supports dynamic type. we can achieve this using 'dynamic' key word.
in dynamic type , c# compiler wont check the type (type safty- we knows that c# gives high periorty to type safty).
but it will check at run time.(if any problem in type conversion CLR will through runtime exception).
Example:
public Class TestCls
{
public void store(int a)
[Code]....
I have this code working. It sets the Visible property of controlToSecure to False. [Code] However I would like to get rid of hardcoding types of properties. In this case i'm hardcoding Boolean. Instead I would like to define the property type dynamically. I tried it like below but I get an error on line 2 "Type property Type is not defined". I just defined that type on the line before though? Does anyone know why this doesn't work and how i could get it to work? [Code]
View 3 RepliesI work on representation layer . My friend work on datalyer( back end) I only get a value which is datatable type. How can i show it to crystal report.
View 3 Repliesi'm using VB.net 2003 application program. i'm trying to convert a VB6 program to VB.NET. The VB6 code i'm trying to convert is shown below. declared g_Share() array in module and trying to add values to it inside form.
[Code]...
i'm using VB.net 2003 application program. i'm trying to convert a VB6 program to VB.NET. The VB6 code i'm trying to convert is shown below.declared g_Share() array in module and trying to add values to it inside form. VB6 (Code inside Module)'Global type array to hold printer info.
Public Type OShare
PrinterName As String
BackupName As String
CurrId as Integer
End Type
'Declare dynamic array for printer info as user-defined type declared above.
Public g_Share() As OShare
VB6 (Code inside Form)
Public Sub LoadPrinters()
[code]....
when pgm runs and when it reach ".PrinterName = myReader(0)" line, it crashes. Object reference not set to an instance of an object. using immediate window i can see the myReader(0) value. how can i create dynamic array for user-defined type in vb.net?
i'm using VB.net 2003 application program. i'm trying to convert a VB6 program to VB.NET. The VB6 code i'm trying to convert is shown below.
declared g_Share() array in module and trying to add values to it inside form.
VB6 (Code inside Module)
'Global type array to hold printer info.
Public Type OShare
[Code]....
how can i create dynamic array for user-defined type in vb.net?
Is there any way to create an XmlSerializer that stores along with the serialized data the data type, then when deserializing, it automatically identifies the type of the serialized object and creates an object of that type (returned as object).
View 1 RepliesI'm not sure if i titled this question properly or am asking it properly, but here goes.I've got serialized objects (in XML) stored in a database, along with a string/varchar indicating the type.
[Code]...
I am currently making a server monitoring application that pings the server to check its uplink, so far it creates all the picture boxes and labels for each server, and then pings the server, although I have a picture that I want to change dependant on the result.
Below is the code I am currently using, the problem occurs with the objectname variable which allows dynamic coding, where i get a error, saying that "Public member 'image' on type 'String' not found".
Private Sub Ping()
Dim i As Integer
Dim objectName As System.Object
For i = 1 To count - 1
[code].....
i have created a dynamic tabpage and a dynamic tablelayoutpanel inside it then added dynamic textboxes and labels inside the tablelayoutpanel...the thing is , i am having a problem on how to access the value of those textboxes and labels and add them as new columns in the new table(tagpage) in mysql database, i can already create the table in the database but i cant add the new columns in it. heres the code for accessing the values of the labels and textboxes
error: NullReferenceException was unhandled....Object variable or With block variable not set.
sql = "alter table " & tbl_selected(counter) & " add " & frmMain.Controls("TLP_" & SecArrList_sp(counter2)).controls.item(SecArrList_sp(counter2) & "label" & counter).Text & " varchar(100) NULL;"
I would like to bind a DataGridView to a different LINQ query every time (in order to reuse the same form/DGV for different queries), like this:
[Code]....
but the "Qry", and the number of comboboxes, and their field names would change every time.
Basically i have one TabControl with a form and 2 browsers within one form I have ProBlem To call the dynamic browser to navigate with dynamic Textbox.text
[Code]...
I need to represent the following query using LINQ:
DECLARE @PurchasedInventoryItemID Int = 2
DECLARE @PurchasedInventorySectionID Int = 0
DECLARE @PurchasedInventoryItem_PurchasingCategoryID Int = 3
DECLARE @PurchasedInventorySection_PurchasingCategoryID Int = 0
[code]....
Now, I know that a query in .NET doesnt look like this, this is my test in the SQL Design Studio. Naturally VB.NET variables will be used in place of the SQL local variables.My problem is this: All of the conditions after "WHERE" are optional. In that a query might be made that uses one, some, all, or none of the conditions. V.PropertyID and V.Value can also appear any number of times.In VB.NET I can make this query easy enough by simply concatenating strings, and using a loop to append the "V.PropertyID/V.Value" conditions.I can also make a Stored Procedure in MS SQL, which is easy enough.However, I want to accomplish this using LINQ.
Ive managed to dynamically create a form, and dynamically create a timer, but i have not been able to create the timer on the dynamic form. Specifically, i need to be able to have the timer itself create another form with a timer. (I realize that this would create a new form every interval on the timer, that is what i want to do)
1. A way to add the timer to the dynamic form, and maintain the timer sub on my main form.
2. A way to create the whole thing over (dynamic form and timer) through the previous dynamic form and timer.
I was thinking i could use a collection/array to store the forms and timers, but i'm still having trouble figuring out how to add entire forms or timers into a list. (A timer is not considered a control, so i cant use a controlcollection...)
Heres my code;
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim frm As New Form
[Code]....
*EDIT* Btw, my idea was to use i as a variable that increases every time a form is created, then insert the form into the array, with i as the integer. i just need to know how to create a new form with a different name each time. (as with timers)
I have a form that i need to be 100% Dynamic. So it could contain 10 labels maybe 100 who knows.
When you hover over a label there will be a different contextmenustrip to appear for each and every label. So all the contextmenustrips are Dynamic and contain 1 option maybe 2 options even 3 or 4 up to the users settings.
My problem is not creating a handler for when the user clicks on the contextmenustrips options. The problem is knowing which one of the options for that contextmenu was clicked!!
OK, I'm trying to display tooltip text for a dynamic edit box. Well, at least I'm trying to.
On my form, I've got a tool tip control which I've conveniently named ToolTip. My edit box displays OK. But, what I want to do is when the user hovers their mouse over the text box, I want the tool tip to display some text.
I think there are two problems that I'm having. I'm not convinced that I'm properly addressing a dynamic text box name. Ideally, I would want to be able to refer to the text box (but using a dynamic variable that will contain the prefix of the name). To hardcode, I would want to be able to achieve (not in this example but in theory): ABCDEFGt_0300.Text = "hello"
Dim controllerName as string = "ABCDEFG"
Dim t_0300 As New TextBox()
Me.Controls.Add(t_0300)
[Code].....
I'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].....