Equivalent For [Field: NonSerialize] (object Cloning)?
Mar 3, 2009
I am attempting to deep clone many of my objects via serialization. Most of it works fine, except when the original object has event handlers for their events. Then the holders of the event handlers are being cloned as well. Anyways, from web browsing it appears the right way is avoid cloning the events. However, you cannot put <NonSerialized> in front of an event declaration, but the C guys seem to get around this by writing [field: NonSerialize] (I guess directing the program to the underlying field, over my head). What is the VB .Net code equivalent to this, as I can't find it?
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Sep 14, 2011
I have a form that accepts a byval client object in the New
private _client as clsClient = Nothing
Public Sub New(ByVal client As clsClient)
InitializeComponent()[code]....
On the calling form I have labels bound to the properties of the _client object, like first and last name.On frmEditClient if have textboxes bound to the same fields.What is happening that I don't understand is that when I'm showing the frmEditClient as a modal window of the calling form, when I change the first name, for example, the labels bound to those fields on the calling form are also changed as I type, indicating that they both point to the same object.
Now this is rather cool, but I expected the object to copied and a new instance to exist in the frmClient modal form, but obviously it is the same instance.Is this because the object is a reference type and so by specifying byval in the frmEditClient creator has the same effect as passing byref? I wanted a separate object in case the user edited the object in frmEditClient and then decided to hit the cancel button and not commit the changes. In this case, do I need to clone the client object before I send it to the frmEditClient?
Like this:
dim _cloneOfClient as clsClient = _client.Clone
Dim f As New frmEditClient(_cloneOfClient)
If f.ShowDialog() - DialogResult.OK Then
_client = f.Client
End If
Problem: There is no clone method. How do I get a copy of an object that is a new object?Or is there a better way to do what I'm trying to do?
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Jun 19, 2010
Away back in the days of "dBase 3+" and "Clipper" we had a useful command called "COPY STRUCTURE" for copying the structure of a database table without copying the data. Does VB.NET have a similar capability for cloning a DataGridView and for cloning a DataSet?
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Jun 23, 2011
is there something equivalent to fileinfo.exist to a Uri object?
for eaxample if Uri.exist=true then do something
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Nov 3, 2009
for Types, we could call toString and convert that into a String, but i would like to do the reverse i.e getting a Type object from its string.
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Feb 3, 2010
If have a control that acts like a record selector from a database, say, for example, customers. The control must act in certain ways allowing the user to type the name, the alias or the code of the customer, and the control will select the correct one, or offer a list of possible candidates, and other behaviors. I have tried to inherit from ComboBox, but there are some ComboBox behaviors that make it difficult or impossible to do what I want, so I'm better starting from scratch, with a TextBox and Button.
The questions are: Do you know some open-source component so I don't have to start from zero? Have you already done something like this and want to share methodologies or tips? Am I good with a TextBox, a Button and a PopUp control?
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Feb 4, 2010
I have a groupox in a VB.NET winform app. The groupbox contains a few Labels, Textboxes and Checkboxes. This was created by simply dragging the controls out of VS toolbox. What I need to do is take the 1 Groupbox and at runtime create multiple Groupboxes to display based on user selection. Instead of dynamically creating the Groupboxes and other controls nested inside, is there a way to clone or copy the original one. Then I'd just change the properties. Label text, Textbox text, etc. And the location of the Groupbox in the layout.
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Jun 15, 2011
I'm currently trying to write a program that will clone input from one program and broadcast it to 4 other windows (Mouse and keyboard, with the exception of the enter key). This is for a World of Warcraft and it is legal. I thought that I would use setWindowsHookEx, but I can't figure out how to set it up that it only takes the input from one window and not globally.Can anyone recommend the best way of cloning keyboard and mouse messages ? or give me an example of how to set a windows hook for only one program ?
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Nov 12, 2010
How to access the fullpath field in a fileinfo object
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Mar 2, 2010
I want to write a routine that loads a table (or query) and outputs it to a text file, with the field names in the first row.If I load the data via an adaptor class into a datatable, I can access the field names by something like DataTab.Columns(i).ColumnName.
As I only want to read the data from the table, using SqlDataReader would be more efficient. But how can I then find what the header or column names are? The following code fails with a message that the SqlDataReader class does not have a member called 'Columns ':
Dim sqlCmd As SqlClient.SqlCommand = New SqlCommand(SQL, Connection)
Connection.Open()
Dim Reader As SqlClient.SqlDataReader = sqlCmd.ExecuteReader()
Dim FName0 As String = Reader.Columns(0).ColumnName() '<==FAILS
Is there a way to find the column names of an SqlDataReader object?
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Mar 24, 2011
[code] I get this error Name of field or property being initialized in an object initializer must start with '.' How should I write this? Or is there an alternative way of doing this?
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Jan 21, 2009
Im working on a small program that is suppost to make my life easier but im running into a little problem:I want to search active directory using the Description field as the search field but somehow my code below doesnt return anything.[code]
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Apr 15, 2009
Hi, I'm just beginning to teach myself how to do OOP in VB 2008 Express. I have a quick question after seeing a video online.Is a VB variable the equivalent of an 'instance' in Flash and a VB object like a 'symbol' in Flash? Is this what it means by a variable being a reference or pointer to an object and not the object itself?
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May 28, 2012
I've got a custom NumericEditor control that has a nullable Decimal property called Value. When I bind a data field to Value, I'd like to retrieve the underlying Type of the data that's bound, so that I can restrict the use of decimal places if the source field is an integral data type.I figure I'd have to do this in the BindingContextChanged event, but how do I get the Type of the data field from the binding itself? My Google-Fu is failing me at the moment.
In short, I'm looking for something like the GetValueType method mentioned in the following question: Simple databinding - How to handle bound field/property change. Winforms, .Net I imagine this method would also be handy if the Value property was an Object.
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May 29, 2012
Suppose I have a list of Cat.
Public Class Cat
Public Property id As Guid
Public Property name As String
Public Property race As catRace
End Class
How can I quickly transform this List(Of Cat) into a List(Of Guid) using the id property?
I could do :
Dim newList As List(Of Guid)
For each item in catList
newList.Add(item.id)
Next
But I think there must be a way to do this faster (1 LOC). I just can't find how.
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Feb 9, 2010
[code]......
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Jun 16, 2009
Error in VB code "Name of field or property being initialized in an object initializer must start with '.'_"
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Feb 24, 2010
I am building a data based application using VB 2008 an SQL Express. I need to create textboxes on my form using code, (With & End With) method. I need a simple code string that will allow the app to check if the field to wich the textbox wil be databound is Nul, If so the textbox will not be created.
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Feb 7, 2011
There are lots of questions about this but I've not been able to solve my problem using the answers to any of them (after many, many attempts..)
I'm working in vb.net creating an asp.net web application. I have an SqlDataSource and a GridView on my page.
I want to change the DoNotMail boolean value represented by a Gridview checkbox and automatically update in the database if the checkbox is checked from 0 (False, Will Mail) to 1 (True, Won't Mail) here is the code I used. [code]...
is it possible to do a two way sync on the entire gridview when the user hits a button so you don't have to do an update every time a row is changed? because the user might check the box and then check another box then uncheck a box and it would be a lot of updates...
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Oct 5, 2010
Dim query as String = "Select * from openquery (devbook, 'SELECT wb.arrival_time FROM web_bookings wb ')"All I need is to convert my arrival_time into a datetime field in the query
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Jun 28, 2010
I am trying to edit a dbf table. I would like to be able to rename field headings and change the field type, ie string or dbl, and the size of the field. is this possible to do with vb.net. I have connected to the dbf file but after that am lost on what to do.
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Jul 10, 2010
I am somewhat new to object oriented programming and am attempting to flatten a Linq object hierarchy by using a shim class.how to initalize a derived class with property values from a base class?I have two objects, a base object with about 100 properties, and a derived object which inherits from the base object and adds a few additional properties beyond those of the base object. My simple constructor creates the derived object, but I am looking for a way to initialize the derived object properties with values from the base object.Right now I am using reflection to iterate over the properties individually and I suspect there may be a better way. The following example shows my shim class constructor for the derived class, and two properties:
newProperty1 - a new string property of the derived class
flattenedProperty2 - a new string property of the derived class, copied from a 2nd-level object of the base class
Code example:
Public Class derivedObj
Inherits baseObj
Private _newProperty1 As String[code].......
Is this the correct constructor approach to flatten the object hierarchy using a shim class? My second question relates to initialization of properties in the derived class. The constructor above creates the derived object, but what is the best way to initialize the derived object properties with values from the base object? The following code uses reflection to iterate over the properties individually, but I suspect there may be a better way.
Code example:
' property names are in the string array fieldNames
'baseObjQuery is an ienumerable of baseObj
'derivedObjList is a list of derivedObj[code].....
Is there a simple way to initialize values for the properties in the derived object based upon the values of the common properties in the base object?
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May 1, 2009
I need to set a field that i have dumped into a dictionary to a value that is always a string, (well, it came from an xmlElement, so the .value is a string)
Function setMembers(ByRef ClssObj As Object, ByRef nLinkObj as Object, ByRef xml As XElement) as integer
Dim fields As New Dictionary(Of String, FieldInfo)
[code].....
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Feb 16, 2011
I created a local Database in VB2008 with 4 tables, the problem is that I have a textbox in one table and a combobox in other table and I want that the information that I put in textbox appear after in combobox from the other table... that's possible?
Table: Filmes ... Field: NomeTextBox
Table: Tempo de Aluguer ... Field: Nome_FilmeComboBox
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Jul 29, 2011
I am getting following error whenever I want to use IIf function inside entity framework query.
LINQ to Entities does not recognize the method 'System.Object IIf(Boolean, System.Object, System.Object)' method, and this method cannot be translated into a store expression.
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Oct 14, 2010
I know that AndAlso is equivalent to && and OrElse is equivalent to ||. But what is the cleanest way to achieve the equivalent of Visual Basic's And and Or in C#?For example, consider the following VB.NET code.The ValidateForControl method performs some validation and returns whether the state of the specified control is valid. The entire input form is valid if all controls are valid. However, each control must be individually validated even if one is invalid (which requires the operator not to short-circuit). Visual Basic's And operator is perfect for this situation, but unfortunately there's no equivalent operator in C# as far as I know (&& short-circuits).
[Code]...
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May 24, 2012
I am Validating a TextBox on it's KeyPress Event in VB.
VB.Net
If InStr("0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz`~!@#$%^&*()_+|[]{};:<>/?,.'" & """" & Chr(8), Chr(KeyAscii)) = 0 Then KeyAscii = 0
What will be it's equivalent in C# ?
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May 18, 2012
Let me know how can i use this Err in c#.This is VB Code:
If Len(sPart1) <> PART1_LENGTH Then
Err.Raise(vbObjectError, , "Part 1 must be " & PART1_LENGTH)
[code]......
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Jul 14, 2011
What I am trying to do is to check if a value matches one of two numbers (and easily be able to add to the numbers to compare to). Rather than doing a longer-winded way such as: [Code] I have found that this only works when SectionID is 2 or PageID is 8. If SectionID is 3 or PageID is 12 then it doesn't work. Why is this and what can I do to try to get around the problem?
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Sep 1, 2010
what is the equivalent for OLE in .net
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