I think it is possible to overload the operator() aka "function call" as OdbcDataReader uses it. using OdbcDataReader("myField") is the same as using OdbcDataReader.Item("myField"), I want to be able to do that for my own class, is this possible, how? I've been trying with overloaded operators but no success.
View 4 Replies
I recently got a vb book, and the operator overloading sample is quite confusing. understanding why you need to overload an operator, and what's the simplest example?
View 7 RepliesIs there a way to use CodeDom to generate an overloaded operator in Vb.net? I want to generate this:
Public Shared Operator =(ByVal x As MyType, ByVal y As MyType) As Boolean
Return x Is y
End Operator
The closest hack I can think of to do this the following:
Dim eq As New CodeMemberMethod()
eq.Name = "Operator ="
eq.Parameters.Add(New CodeParameterDeclarationExpression(New CodeTypeReference("MyType"), "x"))[code]....
Which generates this, close but obviously wrong:
Public Shared Function Operator =(ByVal x As MyType, ByVal y As MyType) As Boolean
Return (x Is y)
End Function
I am trying to convert a DLL function call which has the Callback function routine called within the DLL function call.The DLL function call signature is like this:
typedef void *HANDLE;
typedef HANDLE HACQDESC;
DECLARE_HANDLE (HWND);
[code]....
how to convert this DLL call to VB.NET and also how to create the callback function and send it as parameter to this function
call.
So I'm writing the equality operator overload (Operator =())for a custom object, and the resulting mess of If conditionals is just an eyesore. But so far, it seems like the only sane way to check the values to as to match the specific behavior of this object.
The rules are:Num1 is required, period, and both the left and right operands and must be equal for True. Else, False.Num2 is optional, but if specified, must be present for both the left and right operands, and must be equal for True. Else, False.Num3 is optional, but can only be specified if Num2 is also present. Else, False.Num3, if specified, must be present for both the left and right operands, and must be equal for True. Else, False.
[Code]..
I also know that I could cache elements of the checks into booleans and then use those to reduce the amount of text. But that seems like a waste of cycles just for code readability. So I wanted to know if the SO community had better thoughts on reorganizing it, just in case I'm being too verbose with my checks.
What I am doing is generic and has been done a thousand times, but I can't figure out how other programmers do this.
I am working with the Law of Sines to return an angle of A. There are two combinations, for instance:
Return Angle A given (side b, side a, angle B)
Return Angle A given (side c, side a, angle C)
----Note: All together there would be six, two for each angle)----
I can't overload the functions because the signatures are not unique. The parameters and return type are primitive type Double.
The use of Aliases works for reading the code but does nothing to resolve my issue.
One approach I thought of was to create a structure for each side and angle; however, I don't want to create any more complexity than needed.
Another solution could be using a strategy design pattern?
Public Sub MyFunction()
Dim lowstring As String
lowstring = "hi"
Me.RichTextView.Find(lowstring, 0, 2)
End Sub
The above produces the error of Overload resolution failed because no accessible 'Find' can be called without a narrowing conversion:
Public Function Find(characterSet() As Char,
start As Integer, end As Integer) As Integer:
Argument matching parameter 'characterSet' narrows
from 'String' to '1-dimensional array of Char'.
Public Function Find(str As String, start As Integer,
[Code]...
I'm trying to undersatnd the syntax of calling a funciton and it seem confusing when I'm using a web service in ASP.net. Maybe this question should be in an ASP forum, but it is a VB question. This simple web service allows you to type in your name and it response with an alert box with you name.
My question is, How can you call a function with 2 arguments when the function is only defined for one. I understand that the second argument is actually a method that handling the respons, but how can you interchange function arguments for methods and how do you know that there are methods for
Here's my call:
<script type="text/javascript">
function HelloWorld()
{
var yourName = $get('txtYourName').value;
[CODE]...
I want to create an ExpressionTree where a Func(of Vector, Vector, Vector, Vector, Double, Double, Vektor) should be called. So I use
Expression.Call(Forces(0).Function.Method, {Vec1, Vec2, Vec3, Vec4, Double1, Double2})(Vec1-4, Double1-2 are declared as ParameterExpression and Forces(0).Function as Func(of Vector, Vector, Vector, Vector, Double, Double, Vector). But I get an AgrumentException, because Forces(0).Function.Method has seven Arguments. (System.Runtime.CompilerServices.Closure as seventh argument at Index 0).
I can do this without problem.
Class A
End Class
Class B : Inherit A
End Class
Dim Obj1 As A = New B
I've create a new project, and set treat all warnings as errors in the compile tab.All the other warnings seem to be treated as errors, except the one which I'm interested in "Function/Operator without return value".I have a simple function within a class, which does not show an error if I do not add a return statement to that function. I have read in many places that VB.Net returns a "hidden" default value if the returns statement is forgotten.My software went out to production where an overloaded function was missing a return statement, which wasn't highlighted due to the above.
View 20 RepliesThe is a calculate function for example Function Calculate (Byval v1 as integer, Byval v2 as integer, byval op as ????????) as double return v1 op v2
End Function Anybody tried this?
I don't want to use functions for every operation (multiply,divide, etc.). I wanna pass a operator same as I pass the values. How come nobody ever had this need in VB? Using enums could work but still...
How can I call a function from inside another function and suspend the calling function until the called function is finished? I hope I can get some replies because I don't know how to ask the question and make sense:).
Anyway what I am trying to do in steps:
1. The user clicks button1 which triggers the click event.
2. From the click event I call a function
3. I then pop-up a form, that has instructions for the user to read.
4. After the user has read the form he will click the "Done" button and return to the calling function.
The problem is the the calling function continues to execute. I want to stop execution of the calling function until the users clicks the "Done" button on the instruction pop=up. I know I can use a msgbox but the instructions can be lengthly and does not look good in a msgbox.
I have tried the Call method with return in the "Done" button click but I can make that work. I also tried a goto statement but I can get that to work either. In the call statement I said call frmInstruction.show() and it got there but as I said the calling function continued to execute.
ive two custom controls, which are used to draw and edit etc...(like paint but customized....) i want to save their images with a single click....So im using the Getimageofcontrol function to do it....its code is below:::
Public Function GetImageOfControl(ByVal c As Control) As Image
Dim rc As New Rectangle(c.PointToScreen(c.Location), c.Size)
Dim i As Image = New Bitmap(rc.Width, rc.Height)[code].....
and the code to call this function for saving the images is simply.. ...
GetImageOfControl(pboxd).Save("c:78.jpg")
GetImageOfControl2(pboxf).Save("c:lp.jpg")
but the problem is that both the images have the same content....
I have a function where I am performing a lot number of database operations inside a Sub. The operation when called directly like:ExecProcess()
takes about 11 seconds to run.However, if I create a Delegate, and call the sub using BeginInvoke(), the very same process takes over 40 seconds to execute.Here's the threaded code:
Protected del As ProcessDelegate
Protected Delegate Sub ProcessDelegate()
del = New ProcessDelegate(AddressOf SELocal.ExecJob)
Dim cb As New AsyncCallback(AddressOf Me.ExecJobComplete)
del.BeginInvoke(cb, del)
Anyone know what may cause a function to take longer inside a new thread, rather than calling directly?
Some programs implement command parameters, Like my favourite computer game - Crysis - has them and windows media player has them.But how could i implement them in VB.NET..I want to have a component of my program built as a seperate exe - so it can be an Optional component.But of course the seperate exe, on load, needs data passing to it.So i need something like Process.start("Componentname.exe", "/StartDL <Suchandsuchastring>)/StartDL will need to call a function, and the string that it uses will be given to the function to initiate a download?
View 9 RepliesI am attempting to inherit an ASP.NET RegularExpressionValidator and add some functionality to it. I inherited the control and added my custom properties. However, I would also like the client-side functionality to call a different JavaScript function.
In order to do that, I will need to supress what is happening in the AddAttributesToRender method because the name of the function is hard-coded there. Here is what comes up in Reflector for the AddAttributesToRender function in RegularExpressionValidator:
[Code]...
Note: I tried to add the expando property before the parent class does to see if the code would check for its existence and skip it, but that just causes an exception.
I'm making an app in VB.net (.NET 3.5), using Oracle 10g XE, trough ODBC, I need users log in, to verify if user exists, I can validate if the query has rows of not, I've found property, but when I used it, some error appeared. Is there any other way to make that?
View 2 RepliesI arrive from years with Oracle plsql. Now I'm trying vb.net I created a function that return a char value, so written:
[Code]...
The question: I will create a function get_type(...) in vb.net that calls the tsql function written above... how can I call the tsql function [abc].[GET_PERSON_TYPE] in vb.net function get_type(...) function?
It is really too bad that Microsoft (who once had the best documentation in the business) has slipped so badly. Good documentation does not really require analysis, though, admittedly, it is a lot of work. To wit: for each and every single method, function, event and operator provide the following: a brief topical functional description including any parameters, a detailed description of how the object works, a workable example of the code needed to make this object do something useful and links to all possible associated objects (See Also).
I see pages upon pages of useless text and links to other pages full of links. This rapidly descends into a crevace of unbelievable complexity for the developer trying to find out something truly simple like filtering a DataGridView without changing the data connection. (As it turns out this is very simple to do but I could not find a single example of how to do it in the Visual Studio documentation.)
Any links to good descriptions and/or tutorials (with VB.net 2008) on OdbcDataReader? I tried, but didn't find many. MSDN is not such a good help in this case.
View 1 RepliesI am trying to call a php function from .net. I tried to a webrequest method but I am not sure how to specify the function to call in the url. A link below shows the method I am trying to call.[URL]..
View 2 RepliesI have created a new Class Library in visual basic and called it 'TestDLL'. I have a TestDLL.vb file where I put in this code
Class TestDLL
Function ReturnHello() As String
Return "Hello"
End Function
End Class
Then I clicked on the build tab and built the solution. I then copied the DLL 'TestDLL.dll' to C:TestDLL.dll
I am trying to use that DLL in a console application. I have tried this code but I get an error: System.EntryPointNotFoundException was unhandled Message=Unable to find an entry point named 'ReturnHello' in DLL 'C:TestDLL.dll'.
Declare Function ReturnHello Lib "C:TestDLL.dll" () As String I have added TestDLL.dll to the references for the console application and got that to work, however my goal is to load and unload different .dll files without restarting the application. I have a lot more code besides this, but I'm just trying to find out what commands I could use for just calling functions from DLL files.
There was something I was reading about assemblies, but all I get that to do is list the classes in my dll file. I will already know all the names and locations of the .dll files, and also the class and functions that they contain, because I will be building all of them. how I can get a simple function return in my console application.
How to declare following function in vb2010?[code]
View 5 RepliesI have in vb a selector
Dim ver =101
Select Case ver
Case 101
upd101()
Case 102
[Code]...
How can I make this select better by calling function in more dynamically in this form: with the prefix "upd" followed by a ver integer.
I have a public function to call default email client.Public Function OpenEmail(ByVal EmailAddress As String, Optional ByVal Subject As String = "", Optional ByVal Body As String = "") As Boolean
[Code]...
i have a java script function which help to calculate the total cost by taking the price * by the quality
<script type="text/javascript">
$("[id*=txtQuality]").live("change", function () {
if (isNaN(parseInt($(this).val()))) {
[code]....
I am using textbox(txtFileType) with event OnFocus=("this.blur();"), so I can't use textchanged event for this textbox, I have written a vb code to calculate my FileNumber using Storeprocedures based on the value of textbox(txtFileType). Can I call this vb code from javascript which can be used in clientside.. please help with an example..
View 2 RepliesIs this possible? Every x minutes I need my app to verify something.
Ex:
verify:
'code to verify
[code].....
I've got a program that has a text box with a list of files that are on any removable media. Suppose you launch the program and there's nothing in your CD-ROM drive. Right now, you'd get nothing, and you'd have to insert a disc and click a "refresh" button, which triggers a function that repopulates the list.
Is there any good way to call this function on the event that the user inserts/removes a CD-ROM from any CD-ROM drive? Also, inserting/removing external disks and flash drives? Without having to constantly poll the drives. Floppy disks aren't important to me.
