In trying to add a bit of usage variety to a generic class I'm working on, I ran into this issue with trying to cast an object into an interface instance where the interface is defined inside the generic class.
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I have a following code which works fine
MsgBox(AddSomething(Of String)("Hello", "World"))
Public Function AddSomething(Of T)(ByVal FirstValue As T, ByVal SecondValue As T) As String
Return FirstValue.ToString + SecondValue.ToString
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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 have a question about ASP.Net, visual basic I have 2 LINQ query's, the first one works, the second one doesnt, produces a
"Unable to cast object of type 'System.Data.Objects.ObjectQuery'1[SelmaV2.Products]' to type 'System.Collections.Generic.List'1[System.String]'.
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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 RepliesThis is my
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This is my error: Operator '=' is not defined for type 'FileInfo' and type 'Boolean'.
Following is my code. Private Structure DISPLAY_ELEMENT_TYPE
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Actually this is vb6 to .net converted code. I m getting compile error at following line
temp = Lset(DispElem(i)) bcz Lset is not supported in .Net Lset accept string data type for first parameter and interger for second.If you know any alternet solution or if you have any source code for Explicit convert UDT to string type and vice versa.
Public Pixels(0 To 95, 0 To 127) As Variant Red = Pixels(X, Y) And &HFF i get this code from VB6, and when i transfer to VB05 i got problem said " Operator 'And' is not defined for type 'Color' and type 'Integer'. " i sent to VS2005
Public Pixels(0 To 95, 0 To 127) As Object
Dim red As Object
Red = Pixels(X, Y) And &HFF
I have a generic Class I'm using to hold information loaded from a database.I have a method which takes a DataRow as an argument, uses the object's known column name and extracts the data from the DataRow, such that:Dim loadData As T = CType(myDataRow("myColumnName"), T))works as my default assignment in most cases.Unfortunately, due to some horrifying design constraints, some of my columns may be null, and may also be taken from enumerations.This means that when <T> is Nullable(Of SomeEnumeration) the above code does not work because I can't cast 0 directly to SomeEnumeration.Zero.Is there some way to check whether <T> is Nullable(Of [Enum])? Or some way to write a method which allows Integers to be cast to Nullable(Of [Enum])?I feel like I'm forgetting something that would allow me to write one of the other of these, but my weak google-fu is turning up nothing.
EDIT: Okay, thanks to dasblinkenlight's answer below, I can detect when this circumstance is occurring, but what I need to do now is to take a type <T> which I know is Nullable(Of SomeClass), get a type reference to SomeClass and then create a new object of type Nullable(Of SomeClass) and assign that to LoadData.My problem was that I had a lot of difficulty in finding any function which would accept baseType as an actual Type.Parse accepted baseType as a parameter, I knew baseType was an [Enum] type because of dasblinkenlight's code, so I was, in this instance, able to code a solution. It's a solution which is very specific to my problem (i.e., T is Nullable(of SomeEnumeration)), but it's a solution nonetheless.
The following code at run time gives the error - Opearator '=' is not defined for type DBNull and type 'Boolean'.
The reason is the data at the table is set as NULL value.. How can I change it to accomodate the error.
Dim irowNo As Integer
For irowNo = 0 To DgvReturns.Rows.Count - 1
If DgvReturns.Rows(irowNo).Cells(2).Value = True Or
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In my application when i click the button i'm getting this" Operator '=' is not defined for type 'Char' and type 'Boolean'." But when i test it locally there is no problem at all!
View 2 Replies1) VB Allows non-type template parameters2) VB supports explicit specialization 3) VB allows the type parameters to be used as the base class for the generic type4) VB allows a generic type parameter itself to to be a generic 5) VB enforces that all codes are valid for all types of parametrs
View 1 Repliesi want to know how to type cast to user defined type in vb.net.I have a mark object which contains student id , subject name,subject id and mark. I have to read the subject id from a combo box and read corresponding mark value from it to a text box.
View 2 Repliesi am trying to read an existing excel 2007 file from vb.net i used a form with single button and i written code in button click event code is :[code...]
View 1 RepliesI am building a software which will be used to create a remote desktop connection. However I'm getting this error:
Unable to cast COM object of type 'System.__ComObject' to interface type 'MSTSCLib.IMsTscNonScriptable'. This operation failed because the QueryInterface call on the COM component for the interface with IID '{C1E6743A-41C1-4A74-832A-0DD06C1C7A0E}' failed
due to the following error: Δεν υποστηρίζεται τέτοια διασύνδεση (Exception from HRESULT: 0x80004002 E_NOINTERFACE)).
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I have been trying to use vb2008 to automatically update CustomDocumentProperties fields that I have set up within a pro-forma document. I can load the Word application and word document without problems.I want to update the CustomDocumentProperties fields with data read from a dB. To do this I am assuming that I need to iterate through the CustomDocumentProperties fields within the word document and when one is "found" that matches the data I wish to merge then assign the dB value to the field.The problem is that I am getting an exception error when I try to reference the document customdocumentproperties
"Error : Unable to cast the COM object of type 'System._ComObject' to interface type 'Microsoft.Office.Interop.Word.CustomProperties'. ...... "
my code looks like;
Dim WordApp As Word._Application
Dim odoc As Word._Document
Dim BContinue As Boolean = True
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I'm getting an error after sending a list to a web service.This is the code that is calling the web service:
Dim sProgramInterest As New List(Of Integer)
crmService.InsertProspectGetId(sProgramInterest.ToList)
But I'm getting this error.
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And here is the code that produces the error
CODE:
How can i cast this one?
Consider:
Public MustInherit Class Column
Public ReadOnly Property ReturnSomethingUseful() As Object
Get
'return something useful
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But this gives the following error:
Public Overrides Function ParseValue(sValue As String) As Boolean'
cannot override 'Public Overridable Function ParseValue(sValue As String) As Object'
because they differ by their return types.
I accept that you can't do this, but I'd like to be able to preserve the semantics of what I'm. trying to do, which is to have an untyped version that deals with Object, but a typed version in derived classes that knows about the specific type T.
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 Replieswhen a user inputs a value into a text box, i am searching that value in my dataset.although the number that i entered is in my dataset, i am getting this excemption.
View 3 RepliesI have a Journal that records entries for different types: Journal(Of ParentT)
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I am trying to create a list of a generic type in vb.net 2.0 framework.
This is the generic type definition:
Public Class GenericParamMap(Of T)
Public Sub New(ByVal pParamName As String, ByVal pPropValue As T)
mParamName = pParamName
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The compiler does not allow a "T" in the method's parameter because it's not defined, but I'm not sure how or where to define it. I thought it was okay to have a generic method definition.
I am trying to write a generic method, to avoid code duplication, which will create or activate a Form as an MDI children, based on its type. But I have to lines in error (see comments).
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I have tried several ways but can not make this work. We are using .NET 2.0
vb
If DataGridView1.Columns(e.ColumnIndex).ValueType = GetType(String) Then
'this did not work either:
ElseIf DataGridView1.Columns(e.ColumnIndex).ValueType = GetType(DateTime)
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Quote:
Error15Operator '=' is not defined for types 'System.Type' and 'System.Type'.
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a messagebox appear that show user-defined type not defined i had try another code but it still same error.. i'm using vb6
This is the code I am having trouble with.
CultureInfo As Any (this is where it said: Type 'Any' is not defined)
Dim string1 As String = "strWordGuessed"
Dim string2 As String = "StrWordToGuess"
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To correct this error I use the given help that microsoft provides below and i am still getting the error messages can anyone assist me with the source codes if i send some code snippets?Check that the type definition and its reference both use the same spelling.
Check that the type definition is accessible to the reference. For example, if the type is in another module and has been declared Private, move the type definition to the referencing module or declare it Public.If the type is defined, but the object library or type library in which it is defined is not registered in Visual Basic, click Add Reference on the Project menu, and then select the appropriate object library or type library.
I was trying to and an error log to the Global.asax in .net 2008 and i get the error.Type 'DataAccess' is not defined.
<script RunAt="server">
Protected Overloads Sub Application_Error(ByVal sender As Object, ByVal e As System.EventArgs)
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I am create a new project in Vb 2008 Express edition. And back end using MYSQL( MYSQL ODBC 5.1 Driver) . Now running is correctly but Build time have a lot of error in this project depending MYSQL connection part. What can I do...? [code]
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