Using Double.NaN In Optional Parameter On Interface?
May 27, 2010
I have come across something confusing or potentially a bug in Visual Studio 2010 when defining an interface in my VB application: When defining an interface method with a default parameter of type Double, using the Double.NaN constant as the default value causes the code editor/intellisense/precompiler some issues.The following code underlines "INaNTest" and "INaNTest.DoSomething" claiming that 'DoSomething' cannot implement 'DoSomething' because there is no matching sub on interface 'INaNTest':
[code]...
where now "NaN" has been divorced from the "Double." prefix and underlined ('NaN' is not declared. It may be inaccessible due to its protection level.) The code editor has inserted invalid code again.Is there a correct solution to using Double.NaN as the default value for a method as defined on an interface, in VB.net, or is there a fundamental reason why this is impossible?
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Jan 18, 2010
How can I create a nullable numeric optional parameter in VB.NET?
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Mar 14, 2012
How can i create a optional parameter in C# as we create in VB.Net
Public Sub Demo(ByVal a As Integer,Optional ByVal b as integer=3)
End Sub
I want to declare this in C#
[code].....
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Sep 25, 2009
Is it possible to have an optional parameter of the type list?Ex.
Private Function TestFunction(Optional ByRef MyList As List(Of Double))
The real problem is giving the list a default value. When dimming a new list, you can use the code below to give it a starting value:
Dim MyList As New List(Of Double)(New Double() {1, 2, 3, 4, 5})
But even after trying many variations of the above code, I cannot get it to work as an optional parameter.
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Nov 1, 2010
Is there a way to pass an optional parameter to a webservice, instead of having to overload the method?If the webservice user is accessing the webservice directly, I want to do ActionA, if the user is accessing the webservice through my web interface, I want to do ActionA + ActionB.
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Nov 3, 2010
how can use color as an optional parameter in a sub/function?This doesn't work.
Code:
Public Sub WriteLog(ByVal sText As String, Optional ByVal lColor As Color = Color.Blue)
'Code
End Sub
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Mar 22, 2011
I have an object, called 'PERSON' This person object has a title, firstName & Surname property as well as many other which are at the moment irrelevant. It also has a read only property called Fullname which concatenates the two or three parameters mentioned above depending on an optional parameter 'withTitles' passed over when you call PERSON.FULLNAME
PERSON.FULLNAME(true) <- Will add titles if there are any
PERSON.FULLNAME(false) <- Will give the name without the title
Public ReadOnly Property FullName(Optional ByVal withTitle As Boolean = False) As String
[Code]...
I get an error: PERSON does not contain a property of 'FullName'. If I change this to any other property that does not take a parameter it works as expected. Now I'm guessing that the binding procedure can't handle optional or mandatory parameters for object properties, is this right? Is there a better way to do it? I thought about looping through the collection to add them manually but that kinda defeats the object of DataBinding!
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Jul 28, 2010
I have a problem during defining a Sub routine in VB.Net. I am defining a sub routine which is as under
Private Sub ActivateControls(rdbutton as RadioButton, Optional txt as Textbox, Optional txt2 as Textbox)
End sub
When I call this sub routine It gives me the Error that Each Optional Parameter must specify a default value. So, Here I can't understand that what can be the default value of a textbox. What default value I can use here to remove this error.
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Apr 19, 2012
I have traditionally coded empty strings like this "", but for a couple of years now, I have been using String.Empty.I also normally never use optional parameters, but I'm refactoring a solution that's tied into my ERP, and I don't want to break anything. One of the changes was to add a parameter to proc, which pushes a new parameter into the method from which it is called. I coded it like this:
Optional BackReferenceID As String = String.Empty
But I got a syntax error "Constant expression is required." I guess String.Empty is non-deterministic??? Anyway, it seems like a bug. The workaround is of course to use double quotes.
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Sep 22, 2010
I think this is a pretty basic question, but I just want to clarify. If I have a variable with a null value, and pass it as a parameter that is optional, will the parameter get the null value, or the default value?
dim str As String = "foo"
dim obj As Object
//call 1
[code].....
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Aug 25, 2009
I am trying to develop a simple interface for allowing quick lists to be generated from classes. Basically, the interface needs to return an ID and a Name. However, some classes have a calculated name property which is read only, others just use a read/write name property. Basically, all I care is that it has a getter, it does not matter if the property has a setter. How can I write this interface to handle either or without throwing compile errors?
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Nov 13, 2011
I tried the following, but i get the error
constant expression is required
Public Sub ExampleSub(ByVal Test as string,
Optional ByVal fromDate As System.Nullable(Of DateTime) = Date.Today)
'A Great sub!
[Code].....
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Apr 10, 2009
I am hardcoding an insert statement to a database, based on certain details a user enters into a windows form. The form has a few textbox and datetimepicker controls for the purpose. This form enters a single row in a single table in the database.The table has a few possible null columns defined, in those cases where the user does not have any data for those columns at that particular time.
I have to provide controls for passing data to those null columns nevertheless. In my case, I have two such columns that accept null values, and two corresponding controls - a textbox and a datetimepicker. The datetimepicker has a checkbox added to it so that if it is supposed to be null it doesn't pass the default current date value, and remains unchecked to explicitly specify that it is supposed to be null. By default it is unchecked.
My code is structured as follows:
Form1:
'the sub referenced here resides in a dll file in my dataaccesslayer code, and in my actual example is referenced properly.
'I have shortened the code here for simplicity
[code]....
Now it gives me an error whenever the code comes to the executenonquery(), and says something to the tune of "SqlDateTimeOverflow. Must be between 1/1/1753 12:00:00 AM and 12/31/9999 11:59:59 PM."
I think the value of 'Nothing' from the subprocedure's paramter is not being assigned to the sqlcommand's parameter as a database NULL, which is what I need to pass to the database.I know instead of using optional parameters I can easily create overloaded subprocedures where one sub allows not passing values where the column(s) is supposed to null and other overloaded subs permit combinations of which column(s) are null or not. But it is simple as long as there is just one, or at the most two null columns in a table. If I have dozens of null values in a table that the user can choose to enter or not in a data entry form?
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Sep 18, 2009
My problem is this (apologies if this is a little long ... hang in there):I can define a function in VB.NET with optional parameters that wraps a SQL procedure:
Sub Test(OptionalByVal Arg1 As Integer _
Optional ByVal Arg2 As Integer _
Optional ByVal Arg3 As Integer
[code].....
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Dec 20, 2011
I am using Stanav's PdfManipulation2.AddImageToPage(..., Pages) for iTextSharp library (v5.1.3) and was not able to add the image to specific pages: e.g. to add to only page 1 and 3 of a five pages PDF
Dim Pages() As Integer
Pages = New Integer() {1, 3}
PdfManipulation2.AddImageToPage(..., Pages)
Calling AddImageToPage() with the the optional Pages parameter will add the image to all pages though.
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Mar 22, 2012
I want to pass an optional parameter to a function of type System.Drawing.Color. The problem I am having is that when I declare the function it says "Constant expression is required" but I have tried variations of the following, including integers, full qualified indentifiers, even old vbWhite constants to no avail.
[Code]...
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Oct 11, 2011
I tried writing the following TestCase for an NUnit test written in VB.net:
<TestCase("FirstNode", "<node id="FirstNode">")>
Public Sub GetNode_GivenSomeNodeId_ReturnCorrectNode(ByVal nodeId as String,
ByVal expectedXml as String)
[Code]....
The xml-node passed as the second parameter to the testcase is not valid however, as this clearly is not the correct way to escape double quotes. I'm sure I can find a workaround in order to check that the method under test returns the expected XML-node, but I'm curious:
Is there some clever way to pass a string such as this, containing double quotes, as a parameter to an NUnit test?
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Dec 21, 2009
I've got a picturebox on my form which is supposed to hold a compass. I've created the compass with DrawEllipse, then I used a translatetransform() to move the origin to the center of the picture box:
[Code]
The problem is that it creates two images, one is correctly displayed of a compass with red tick marks, but the same image is displayed over it and is offset at the new origin (midx,midy). I tried using the prepend and append overload for the translatetransform sub but it didn't make a difference. I thought everything after the translatetransform would be set at the new origin, but it seems I'm creating the image twice, what am i doing wrong?
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Sep 26, 2011
I have a single instance app that is working fine except for this strange (to me) issue.
The user could double click on FileA and my app opens and displays the file contents (the path of FileA has been passed as a parameter) No problem there. The problem is that if the user then double clicks on FileB and I read the parameter it still contains the path to FileA. What trick am i missing here?
(If i add a debug line that forces the code to be FileB's path the the app works correctly in terms of opening a new tab, reading the contents etc.) (vb.net 2010)
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Jul 18, 2006
Currently, I am using a VB.NET to generate an interface for the user to update parameter of a PCB board MCU. However, I found that some data might be having a problem while transmitting.
Previously, I am using a chrW() to change the transmit data before put into the MyRS232.Write(), however, some data have corrupted or changed while I transmit. The signal show the checksum is wrong while sending the set of data.
After I use an oscilloscope to check the signal transmitted. I found out that, when I sent the data is between &H80 to &H9F (&b 100* ****), the signal will change to &H3E (&b 0011 1111). Anyone have any idea why this happened? Now the temporary solution I found for this one is I use a chr() instead of chrW() for the data between &H80 to &H9F.
[Code]...
I am using another function ChrWt instead of Chr or ChrW only. I remember that, I change from Chr to ChrW because some data corrupt also while I sent using Chr only. Did anyone of you having this problem as well? Any suggestion instead of using another function?
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Mar 6, 2010
I am trying to have an optional Date value in one of my sub but since you cant set Date to nothing, this doesn't work. And i cant set it to the Date.minvalue inline.
Private Sub abc (ByVal A As String, Optional ByVal B As Date = Nothing)
End Sub
So, i went and set it to some date in the past.
Private Sub abc (ByVal A As String, Optional ByVal B As Date = #1/1/2001#)
End Sub
what would be the proper way to handle the default value for an optional Date?
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Jun 11, 2012
I need to create a function which have either 1 parameter with a string as data type or 2 parameters with double as data type.Something like the substring method.
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Jan 27, 2011
I have a situation where I am handling both single & double mouse click events on a form. In both cases something has to be loaded, however when a double click occurs, I do not wish to execute the code attached to the single click event.Is there a way to intercept the mouse click's and check if double or single and then execute the right event appropriately?
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Nov 17, 2010
I have a htpc project that I am working on. The main program loads dll plugins which are basically other win forms. On each of these forms, including the main program, I use a picturebox (a double buffered picturebox) for the background image and then draw everything on it by hand. Whenever I load the form from the dll and show it, I get a weird flicker. It looks like it is the previously used double buffer. Is there any way to clear the background double buffer before the flicker? Or am I going in the wrong direction?
Here's a couple of videos of the problem:
[url]
[url]
Notice the black screen with the white lines on it or the flash of the desktop after I click "Movies." How do I get rid of that?
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Aug 15, 2011
For greater accuracy I should use a Decimal instead of a Double ( so I've been told ). Why then have Microsoft chosen to use DOUBLE for most of the functions that return a floating point value in the Math Class?
[Code]....
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Apr 4, 2009
In vb.net, im using objWriter.Write("playerA= "x"")as you can see im using double quotes inside double quotes, how do i skip it so the error doesnt show up?in php you make an "" to skip the string like ("playerA = "x" ")
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Aug 11, 2010
When i use VB6 i get the following outputs
961.605 * 100 = 96161
936.495 * 100 = 93650
929.295 * 100 = 92929
NOW..... When i do the above in vb.net 2005 i get the following
961.605 * 100 = 96160
936.495 * 100 = 93650
929.295 * 100 = 92930
How can i get the same output as the VB results. And i have tired it ! Type conversions, math functions, everything i can think of to get the same VB6 output !
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Apr 21, 2011
Following code doesnt work and raise error "A parameter is missing. [ Parameter ordinal = 1 ]".What s wrong with it?I am developing pocket pc application in vs 2008 and sqlce 3.5 sp1.
[code]....
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Mar 21, 2009
I'm Trying to Call the Stored Procedure which has one input Parameter and one output parameter . VB.net code is below
[Code].....
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Mar 9, 2011
I want to have a "template" function that can receive different parameter and a type parameter, like:[code]But Vb told me that tupeList is not defined... is there a way I can do that?
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