Delegate Sub UpdateTextHandler(ByVal recbuffpass() As Integer)
Private Sub someSub()
Dim f As frmMain = My.Application.OpenForms("frmMain")
f.Invoke(New UpdateTextHandler(AddressOf f.UpdateTextMethod), New Object() {recbuf})
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I'm wrestling with this treeview control. I have extended the TreeNode class to attach some extra data to the node. Basically, I added one property:[code]Is there a way to cast from a base type to a derived type?
View 11 Repliesi have a property (items) that i want to use for either a checkedlistbox or a standard listbox depending on the value of another property.
heres the code i wrote that doesn't work:
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What happens when a user wants to alocate "" as Item(DurationColumn) to integer? I get an exception. clean solution to avoid this and set 0 for ""?
When writing some Outlook code in VS2005, I came across a situation that, to me, does not make any sense. For reference, the version of Outlook running on this machine is Outlook 2003.The program I'm writing is designed to iterate through the emails in the inbox, to identify certain types of emails based on their subjects and bodies, and then to generate new emails based on the existing ones. However, the problem that I'm having is with simply iterating through the collection of items that comes from the Inbox folder. Specifically, what happens is that this line consistently fails on items that should be processed:
Current_Item = CType(The_Items.Item(Counter), Outlook.MailItem)
I am trying to create an Excel file using reflection. The reason, the application will be running on many machines some of which may or not have excel installed. I decided to embed the "Microsoft.Office.Interop.Excel.dll" and via reflection generated the excel spreadsheet. The code I am trying to resemble is:
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Hmmmm having discovered that using the mciAPI doesn't utilise 5.1 sound, but using a virtual WMP does - I started a new approach to my multimedia project using some code from the net. BUT I keep getting exceptions (particularly with type casting). In the subrountine 'Player_PlayStateChange'.
The listing (see below) is now well commented by me. Can anybody please help concerning the damn annoying exceptions and stop me pulling my hair out.
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When the datagridview's selection mode is set to "RowSelect", the HitTestInfo Type property only returns column header as the type and not the cell that is being clicked on.Is there a way to keep the selection mode as RowSelect and still detect which cell is being clicked on?
View 9 RepliesSo I'm building an application that is going to do a ton of code generation with both C# and VB output (depending on project settings). I've got a CodeTemplateEngine, with two derived classes VBTemplateEngine and CSharpTemplateEngine. This question regards creating the property signatures based on columns in a database table. Using the IDataReader's GetSchemaTable method I gather the CLR type of the column, such as "System.Int32", and whether it IsNullable. However, I'd like to keep the code simple, and instead of having a property that looks like:
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I have one question. i have seen some codes like:
Req = CType(System.Net.HttpWebRequest.Create("url"), Net.HttpWebRequest)
Is it really necessary to cast the same type, or is there a difference when its not casted.
I've got a piece of code in a project (MyProject) that contains early bound object from a referenced assembly (We'll call it CommonAssembly):
Dim myObject As CommonAssembly.MyEarlyBoundType
now I have another assembly that is dynamically loaded because it is not present in all projects:
Dim myLateBoundObject As Object = AppDomain.CurrentDomain.CreateInstanceAndUnwrap("Utils", "Utils.MyLateBoundType")
MyLateBoundType derives from CommonAssembly.MyEarlyBoundType, and I want to cast myObject to myLateBoundObject and then programmatically invoke the additional
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I have the following problem with MEF: Interface definition to be used by host:
Public Interface IExecuteDoSomething
Inherits IAddinSettings
Event DataReceived As EventHandler(Of DataReceivedEventArgs)
Function DoSomething() As Boolean
End Interface
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Everything seems to work fine until the Button2_Click routine is executed, then an InvalidCastException is thrown with the info:Unable to cast object of type 'System.Collections.Generic.List1[SharedLibrary.IExecuteDoSomething]' to type 'System.Collections.Generic.List1[SharedLibrary.IAddinSettings]'.
How can i solve this problem, because the imported object implements both of the interfaces?
The next code works fine in C#:
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But this code crash with a OverflowException in VB.Net.
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Both codes seems the same to me. What is the difference and how can I get the C# code converted to VB.Net?
I have a object type variable (control .Tag) that I need to cast to a structured type, and change a member in. This is a contrived but representative example
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get around this. I have a data base field that is a decimal data type and I want to display it in a text box with the following txtWeekdayRate = CType(RoomsDataRow!WeekdayRate, TextBox)I get the following error when I run my program.Unable to cast object of type 'System.Decimal' to type 'System.Windows.Forms.TextBox'.
View 20 RepliesI am getting the followin error from my code. System.InvalidCastException was unhandled Message="Unable to cast object of type 'QADBASE.DMRDataLists' to type 'QADBASE.DMRData'." Source="QADBASE" I am getting the error in the code below on the createDMRIssue
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Public Function CastToT(Of T)(ByVal GenericType(Of Object) data) As GenericType(Of T)Return DirectCast(data, GenericType(Of T))End Function
The above clearly does not work. Is there any way to perform this cast if I know that all objects inside data are in fact of Type T?
I have an Entity class which Implements IWeightable:
Public Interface IWeightable
Property WeightState As WeightState
End Interface
I have a WeightCalculator class:
Public Class WeightsCalculator
Public Sub New(...)
..
End Sub
Why can I not do wc.Calculate(entities)? I receive:
Unable to cast object of type
'System.Collections.Generic.List1[mynameSpace.Entity]'
to type
'System.Collections.Generic.IList1[myNamespace.IWeightable]'.
If Entity implements IWeightable why is this not possible?
I am passing Date Field to SQL Database. Field is declared as String in the VB.Net Application. I wrote a piece of code for casting to Date
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I'm a C# programmer who is forced to use VB (eh!!!!). I want to check multiple controls state in one method, in C# this would be accomplished like so:
if (((CheckBox)sender).Checked == true)
{
// Do something...
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I have tried everything to no avail. I need to cast the value from a user selected dropdownlist to another dropdownlist on another page. The data in the textboxes are a series of numbers. Also is there a way to display the value in the second dropdown list as well as other values? For example, my dropdown has the values 1-6, user selects 4, which displays first in the dropdown on page 2 but the other values also display in case they want to change there selection??
If Not Page.PreviousPage Is Nothing Then
Dim table As Control = PreviousPage.Controls(0).FindControl("table1")
Dim ddl As DropDownList = CType(table.FindControl("ddlB_Codes"),c DropDownList)
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I'm trying to obfuscate some VB.NET 2003 app.The resulting assemblyes are obfuscated and "run" with some errors.I cleaned all potential reflection problems, but I'm not being able to read the selected value of a combobox.
I load the Combobox using their Datasource properties, using a collection of "VTPair" (a class created by me with 2 properties: one of string type and other of object type to store the value)
This combobox handle pairs like "Male | M" or "Female | F".When trying to see what is selected, I use if mycombo1.SelectedValue = "M" then.This code, after obfuscation, throws me an exception that cannot cast type "XX" to string "M".
So, I changed the code to something more correct, explicitly casting the selected value to String:
if ctype(mycombo1.SelectedValue,string) = "M" then But the error is the same.Debugin my original code, the SelectedValue property is of type "Object" but it is a string.I tried using the ComboBox.SelectedItem property that is also an object but this time what is inside is of type "VTPair" (my own class) and then trying to access its "Value" property (which is of type Object) and trying to cast to string fails again.
Does anyone have an idea to "translate" this piece of code to work OK after Dotfucate it?
I have an object that inherits from an interface. I can create and return the following:
Dim o As IRequest
o = New Request
Return o
This works fine. Now I want to return a List(Of Requests), so I try the following:
Dim o As List(Of IRequest)
o = New List(Of Request)
Return o
The error below is being given on o = New List(Of Request)
System.Collections.Generic.List(Of MyObjects.Request)' cannot be converted to System.Collections.Generic.List(Of MyInterfaces.IRequest)'.Consider using 'System.Collections.Generic.IEnumerable(Of MyInterfaces.IRequest)'
I don't know where it thinks I'm casting.
Here is my property
''' <summary>
''' Gets the GetX509Certificate from a file.
''' </summary>
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and heres where it says im doing the illegal cast:
Dim cert As System.Security.Cryptography.X509Certificates.X509Certificate2 = Me.GetX509Certificate
Why is it saying that? Everything is defined in the right type but it still thinks I'm casting.
in vb, you can use text which is in textbox instead of numerical expressions. I mean, if I write 50 in textbox1 and also I can write like that code:
Dim result As Double = TextBox1.Text + 0.4
as you see, I didnt convert any type but it works in vb.net
But I want to learn what are disadvantages of this using?
(I am just talking about arithmetic operations)
Say I have a interface called IProperties and I have a collection called colMyProperties that is a collection of IProperties. Then I have an object called clsProperty that implements the IProperty interface. Now, in my code where I add objects to the colMyProperties collection I add a bunch of clsProperty objects. so far so good.
Now when I try to access an object in the collection I can only access properties and methods of the IProperties interface, not the clsProperty object. What am I doing wrong? Do I need to cast the object?
I usually avoid VB's built-in conversion functions (CStr, CDate, CBool, CInt, etc.) unless I need to do an actual conversion. If I'm just casting, say from an object to a string, I normally use either DirectCast or TryCast, under the assumption that CStr, etc., are doing some extra stuff I don't need. But sometimes the DirectCast syntax is a little cumbersome, as in the following example.[code]SqlDataReader.Item returns an Object, which needs to be cast to a String. CStr is easier to read, type, and explain (IMO). My question is, does it matter which one I use? Should I just go with CStr (and CDate and CBool, etc.) and not worry about the extra work I assume those functions are doing? Is there any other downside to using these functions?
View 3 Repliesi have the following code which walks through an Excel file and this works fine note that the following line does work well (folder is being set earlier in the code)
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When I have many controls on a Form (i.e. Label, Button etc) that do almost the same thing, I often use one method to handle all the controls Click, MouseDown, MouseUp events.But to know which of the controls throwing the event and access the properties of that control I need to cast the "sender" object to the correct type.
The thing is that I always know which type it is, I don't really have to "TryCast", "DirectCast" and check if the operation returns true. I some times use CType as well.
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I've got a project called Service.Inside the project, i've got 2 windows classes.ClassA is the main windows class which opens up when I run the program.On ClassA, I've got a button which, when I click it, opens up ClassB which is the other windows class. Inside the button's eventhandler (click), I've got a string which contains the name of ClassB's class ie "ClassB". I will probably get this from a table. Is it possible to initiate the object ClassB without using if statments to check what the type of object is. In the code below, i've managed to create a o of type object, but i need to new it with the ClassB
vb.net Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
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