Error: "The Specified Type Must Be A Structure Containing No References"
May 9, 2010
I have created a structure with the following elements:
<StructLayout(LayoutKind.Sequential)> Public Structure person
Public userid As Integer
Public age As Integer
[code]....
I am trying to write this structure using the following lines of code:
Sub testwrite(ByVal filename as string)
Dim temp as new person
Using mmf = MemoryMappedFile.CreateFromFile(filename, System.IO.FileMode.OpenOrCreate, "test", 1000)
[code]....
However, every time I try and run the program I get the following error: "The specified Type must be a structure containing no references."I thought the "MarshalAs" created the array within the structure and therefore wasn't a reference. Can someone tell me how to get round this problem so that I can pass an array.
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Jul 23, 2009
I have to create an array of structure type in VB.net. but I am getting error while marshaling this error. I have to pass this array of structure type in to Dll function.
Code:
Structure declaration:
<StructLayout(LayoutKind.Sequential, CharSet:=CharSet.Ansi)> _
Public Structure dx_entry
<MarshalAs(UnmanagedType.ByValTStr, SizeConst:=10)> _
Public dx As String
[Code] .....
I am getting the following error:
An unhandled exception of type 'System.ArgumentException' occurred in Audit_Demo_2307.exe
Additional information: Type dx_entry[] can not be marshaled as an unmanaged structure; no meaningful size or offset can be computed.
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Jan 5, 2012
Module Module1
Public Structure structure1
Public TRANS() As structure2
End Structure
Public Structure structure2
Public X() As Integer
End Structure
End Module
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Mar 9, 2011
I have Crystal Reports 2008 installed on my win7 laptop but when i go to insert references from my application settings the CrystalDecisions references are missing and im not able to find them. Note: they do exist in my "c:windowsassembly" folder.
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Jan 11, 2011
I am getting the following error when I add a service references that points to a web service.
'System.ServiceModel.XmlSerializerFormatAttribute' is not accessible in this context because it is 'Friend' in the Reference.vb file.
I have not gotten it in other projects that I have done that point to the same web service. I have recently add some code that I downloaded and cleaned up the errors in to my project and this seems to be what broke it. This code uses several new features that I am not familiar with, mainly the "Friend" declaration and also uses name spaces in the code it self. Also I converted the code from C# using an utility that I downloaded, that untility was not 100% in it's conversion, hence the clean up that was needed.
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Mar 7, 2010
Is the integer data type is structure? And if yes what is the original code of it?
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Mar 29, 2009
I have create a structure type array. sort the array so i can display the sorted array in a listbox. I want to be able to either sort by last name or the student with the highest score. Here's what I have so far:
Structure student
Dim firstName As String
Dim lastName As String
[Code]....
I heard about the IComparer thing but I didn't know how to implement it into my project.
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Aug 25, 2011
I've just finished installing VS2010 on my computer. I have a project I built in 2003 that I'm trying to open in 2010. It went through the conversion process and generated this error: System.SystemException - The type library importer encountered an error during type verification. Try importing without class members. : System.MissingMethodException - Method not found: 'Void
[Code]...
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Nov 8, 2011
I epochly failed creating an array structure. How would I build it like I tried to do with values for each data type.
Structure PovertyGuidelines
Dim Id As Decimal
Dim NumberOfPersons As Decimal
Dim AnnualIncome As Decimal
End Structure
Private Data(20) As PovertyGuidelines
Private Id(,) As Decimal = {{1D, 2D, 3D}}
Private NumberOfPersons(,) As Decimal = {{6D, 9D, 7D}}
Private AnnualIncome(,) As Decimal = {{24000D, 32000D, 27000D}}
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Nov 19, 2008
I have a structure like this:
Code:
Public Structure Interval
Public temp As Double
[Code].....
'I want to be able to add to the array like an ArrayList though... 'after assigning values, like this:
interval(0).add
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Jan 22, 2010
I'm about to start translating my vb.net application, and I don't want to use the default methods provided by Visual Studio to do so. I need my application to be very light, and it nearly doubles it size to use the resources option.Therefore, I'm planning to use some thing like a class, of which I would have one instance per language. Since I don't want to distribute language files as separate files (I'd rather have them hard-coded), I would like to find an easy way to check if every field of the class is initialized. I was thinking of something like an Interface, where I would do something like this:
Public Interface Language
Dim HelloMsg As String
Dim GoodbyeMsg As String
End Interface
[code]....
It's obviously not the right way to do it (although I could use properties instead of vars), but I was wondering whether the was a way to have the compiler check that everything is translated and warn about it if not.
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Oct 30, 2010
I found out that you cannot set the array size for a structure when you are making it, i.e
[Code]...
I have to fix this by making a variable with type made by Structure bullet and then redimming it, i.e
[Code]...
This means for every variable with the bullet type i create i have to redim. Is there a way i can set the size of .mesh with .capacity for every single variable created with the bullet type automatically?
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Apr 29, 2010
Im trying to save a structure that consists of regular variables, some of my own structures and rectangles. Now while all the other data types get saved/loaded nicely the rect information is lost, why is that?
save sub:
Dim ForSaving As SaveDat
Dim file_num As Integer = FreeFile()
ForSaving.OVIRect = ESpec.OVIRect
[code]....
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Jul 22, 2011
I've got this Function:
Public Class QueryStringUtil
Public Shared Function GetQueryStringValue(Of T As Structure)(ByVal queryStringVariable As String) As T
Dim queryStringObject As Nullable(Of T) = Nothing
If queryStringVariable <> Nothing Then
If HttpContext.Current.Request.QueryString(queryStringVariable) IsNot Nothing Then
queryStringObject = CTypeDynamic(Of T)(queryStringVariable)
End If
End If
Return queryStringObject
End Function
End Class
When I try to call it like this:
Dim intTest As Integer = QueryStringUtil.GetQueryStringValue(Of Integer)("stuff")
Dim stringTest As String = QueryStringUtil.GetQueryStringValue(Of String)("stuff")
Dim datetimeTest As DateTime = QueryStringUtil.GetQueryStringValue(Of DateTime)("stuff")
stringTest gives me the error:
'String' does not satisfy the 'Structure' constraint for type parameter 'T'.
I want our other developers to not worry about having to convert a class to a structure or some stuff like that when they call this function. I just want them to be able to put a standard type in the (Of T) and have it work. I don't mind writing in extra calculations to achieve that. The other problem is I also need the function to be able to return an actual null value, so I kind of need the queryStringObject as Nullable(Of T). Which means I have to have T as Structure otherwise it tells me that won't work. So looks like if I change what T is I need to run some calculation to delcare the var as nullable or not.
I tried overloading this method so that one returns T and one returns Nullable(Of T) like so:
Public Shared Function GetQueryStringValue(Of T As Class)(ByVal queryStringVariable As String) As T
Public Shared Function GetQueryStringValue(Of T As Structure)(ByVal queryStringVariable As String) As Nullable(Of T)
And naturally it's telling me it can't do that since they just differ by return types. Is there anyway to overload this? I really don't want to have two functions.
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Dec 27, 2009
how to make a new structure somewhat, but what I need to know is how I can do something like, GetItemByName without having to do a loop when I have a list of my structure type. What I mean by this is if I had a structure like this:
[Code]...
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Mar 4, 2010
I have a database table of company information.It's about 50 records and contains things like company id, company name, address, phone number, shipping rate1, shipping rate2,etc.I want to load that table into a structure that I can quickly search within my code.I want to search by id to find the company, and then use the company's data to update some records.My lazy way has always been to add a listbox for each piece of data, then do an indexof on the id, then access the same index on the other listboxes.[code]
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Sep 25, 2009
I have a User defined table type(UDTT) in Sql 2008 I am writing VB Code to send data to Stored procedure that uses it as a parameter I have found that the datatable i build in VB has have columns in same order as udtt when passing it to SQl from VB Currently I have this roughly
In SQL Server
Create type table my_table
Field1 varchar(10)
Field2 varchar(10)
[Code]....
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Mar 11, 2010
hello
I would like to know if it is possible to store an array within a structure. For examples for recording people with more than one name. Like this:
Structure Product_Reccord
Dim PNames(3) as string
end structure
It is giving me an error, help please!!
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Feb 23, 2010
I am writing a program using a structure for the first time. The structure has 10 string variables declared inside each equal to a individual textbox on a form. I need the program to be setup so that if one or all of those textboxes are empty at the time of the event being activated a messagebox is displayed telling the user one of their textboxes is blank. Now i could do this in a series of 10 if then statements im sure but using a structure theirs got to be an easier way.
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May 25, 2011
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
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Mar 1, 2012
I'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].....
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May 24, 2011
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]....
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Oct 10, 2010
I'm getting the error "Conversion from type 'DBNull' to type 'Date' is not valid."here's the line generating the error.
dtReady.Value = dSet.Tables("Db").Rows(Inc).Item("Fixed_Date")
I'm using a date/time picker control and sending the db value to it. I know that the value is null, but I don't understand why the Picker can't be blank. Is there a way to let it be blank? Or should I set up a way to check for nulls and assign today's date or something just in case?
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Jun 15, 2009
how can I solve this error without having to fill all of my fields. Some of the fields in my database are Nulls and some have records.
Error: Conversion from type 'DBNull' to type 'String' is not valid.
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Dec 22, 2010
I have a series of API calls that are returning J# data types. I have been able to convert most of the data types (Integer, Boolean, Double, Float, etc) just fine.What I need to do now is convert a java.Util.Collection to a VB .NET collection (ArrayList)
Here is my attempt:
Public Function MakeDotNETCollection(ByVal javaCol As java.util.Collection) As Collection
Dim dotNetCol As Collection
[code]....
I keep getting a runtime error "Unable to cast object of type 'AbstractListlistIterator' to type 'System.Collections.IEnumerator.
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Feb 24, 2012
I am using a background worker and am attempting to use the following code. However I keep getting this error on i "Unable to cast object of type 'ObjectCollection' to type 'System.Array'."
Private Sub btnVerify_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnVerify.Click
myArray = listProxies.Items()
BackgroundWorker1.RunWorkerAsync()
End Sub
[code]....
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Mar 11, 2011
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]
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May 2, 2010
I am getting the error "Conversion from type 'DataGridViewTextBoxCell' to type 'String' is not valid." When trying to display a cell from DGV in a listbox.I have my variable for the cell reference as follows:
Dim a As Object
a = DataGridView1(4,1)
To insert it in the listbox as follows:
lstLetter.Items.Add(String.Format(a))
I tried:
lstLetter.Items.Add(a)
This will not actually display the entry inside the referenced cell, it shows this in my listbox instead:
DataGridView TextBoxCell { ColumnIndex=4, RowIndex=1 }
how I need to convert this to display.
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Jul 29, 2011
I was tried to get quantity from db make use of the selection in list box. I got answered with listbox1. If i selected the item in listbox1 the quantity would appear in textbox1. But in this same code will not work for listbox2 with textbox4.. Here i given the code...
$Con.open()
$Dim cd as new oledb.oledbcommand("Select Quantity from tlist where tool_name"& "'"listbox2.selecteditem & "'" & "", con)
[Code]....
Here i got the error as "Conversion from type DBNull to type string is not valid"
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Aug 19, 2010
This is my
[Code]...
This is my error: Operator '=' is not defined for type 'FileInfo' and type 'Boolean'.
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