Forms :: How To Handle Each Variable Type Individually
Apr 11, 2010
I have defined 5 variables T1, T2, T3, T4, T5 As Double and set them all = 0. On a form I have a enter information button. Each time the button is pressed I want to assign a different variable, to a text box input. For instance, If I enter 1 that will become T1, and then if I enter 2 and press the button again, that value becomes T2.
I have tried
If T1 = 0 then
T1 = textbox.text
End if
If T1<>0 And T2 = 0 then
T2 = textbox.text
End if
I have tried to use 'else' statements and all kinds of things like that to no avail. I can get the first two variables correctly assigned but three is impossible with my current understanding. Is there a way to do this, or do I need 5 buttons, so that I can control which variable is assigned? To be correct my intent is to create an observation with three variables each time the button is pressed.
For example, the first button press will result in three variables being assigned a value other than 0; they are T1, B1, and R1. I have just begun to understand the concept of arrays and am wondering if that may be the way to go in this situation. I was just going at this in a newbie way I'm sure and trying to handle each variable type individually, and figure out all the T* variables and move onto the B* variables.
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May 25, 2011
Is it possible to replace these two functions
Function f1 (s As String) As class1()
Dim a() As String = Split(s)
Dim b(UBound(a)) As class1
[code].....
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Dec 3, 2009
My app has a group of forms that do a specific work in different ways. I want to create a new variable of a form when I want with its name. So, I want a Function in this form :
Public Function GetNew (byref f as form ) as form
That give a form name and return a variable of that type. In other words, it must work as "dim f1 as new formx".
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Apr 14, 2010
I have this function:
Public Sub DoStuff(ByVal type as System.Type, ByVal value as Object)
End Sub
The 'value' argument is always an array of the same type as 'type'. How can I loop through the values of the array?
I'd like to be able to do something like this:
DoStuff(GetType(Integer), New Integer(){1,2,3})
Public Sub DoStuff(ByVal type as System.Type, ByVal value as Object)
//Strongly types arr as Integer()
[Code].....
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Oct 10, 2009
I'm aware that questions like this have been asked before and I doubt it's possible, but I just wanted to make 100% sure that it isn't.In VB.net or C# (either language, it doesn't matter), I want to cast a variable to a type represented by another Type variable. Here's an example of the kind of code that would be needed in C#:
Object castMe = new Foo();
Type castTo = typeof(Foo);
Foo beenCast = (castTo.GetRepresentedType())castMe;
[code].....
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May 18, 2012
Public Class Form1
Dim x, c, number(0 To 19) As Integer
Dim s As Integer
[CODE]...
The variables in the brackets [example] do not actually have brackets in them in the original code. These are where the issues are. For both variables, it says, "The type for variable [variable] will not be inferred because it is bound to a field in an enclosing scope. Either change the name of [variable], or use the fully qualified name (for example, 'Me.[variable]' or 'MyBase.[variable]')." Now, I'm not entirely sure if this is a stupid question or not, as I'm used to VB '98 because that's what we use in my programming class at High School. let me know why this won't work.
-Note: The intention of this program is to continually loop the generation of numbers for this list until I tell it to stop. Button1 ends the program, Button2 generates the list one time only, Button3 is supposed to loop the generation of the list, and Button4 is supposed to end the loop, but not the program.
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Aug 24, 2009
I am looking for a good resource on variable naming conventions to illustrate variable type and where variables are declared. So I will have public variables, Private variables, private or local variables. I also may want to declare variables with the same name in different class code (i.e. in the code behind different forms). I am assuming good coding would dicatate a prefix for declaration location.
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Sep 17, 2011
I have the following code that I am using to parse out a test file. I am getting variable conversion error in Sub Main() when I assign file = Read(). The return value of Read() is a TextFieldParser type. How do I assign the proper variable type to "file" so I can write the output to a text file?
Function Read()
Using MyReader As New FileIO.TextFieldParser("C:UsersColinDesktopParse_Me.txt")
Dim currentRow As String
[Code].....
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Aug 28, 2010
I need to get the handle of a variable. How do I do this?
DEVICE_PARAMETERS = New PresentParameters
ZeroMemory(>>Handle of DEVICE_PARAMETERS<<, Marshal.SizeOf(DEVICE_PARAMETERS))
-Ren�
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Dec 22, 2009
E.g. how do I get VB.Net to statically type a local variable to be the static type of the expression on the right had side of the assignment?
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Oct 22, 2009
I want to use explicit conversion (CType function in VB.NET) to convert the variable d from double type to integer type and store the result as 132.
Imports System.Console
Module Module1
Sub Main()
[CODE]...
This is my code. But Visual Basic tells me an error: Error1Type 'i' is not defined.C:\Users\mihaispr\Desktop\Conversie explicita\Conversie explicita\Module1.vb1922Conversie explicita
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Jul 19, 2010
I'm developing an app that should allow the client to add several content sections to a page (in tabs). However I haven't found a way to easily create a form for editing the tabs.Assume for now that a tab just contains a title. I have a form that adds a tab, that's simple. But I also want a form that displays a text input for each tab and allows the titles to be edited and saved. I'm struggling with two main concepts:How to dynamically display the fields after grabbing the tab data from the database (each tab has its own row in the table).How to loop through the submitted data and update each tab in the database.How to select a particular text field from the number (e.g. given "1", how to select the element with ID "TabTitle_ 1".[code]I thought something like TabTitle[0] would be acceptable and allow for easy looping (as it does in PHP) but it's "not a valid identifier" apparently.It's very possible I have the approach completely on its head.
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Feb 15, 2010
Writing an asp.net mvc app and i have something like this...
Public Class AA
'... has some variables...
End Class
Public Class BB
[code]....
So, now in my program, i just want to copy object of type AA to an empty variable of type BB?it makes sense to do this, as i expect all the fields in AA type object to be copied to the newly created BB type object, and the ExtraVariable in the BB type object i would (will) just assign a value to it later (after the copy) on my own time!!I know copying BB type to AA type would not be appropriate as there would be lost data!But im trying to copy AA to BB, I've used both DirectCast and CType to do this, and i keep getting "unable to cast" error!
Note: I'm using vb.net (but can read c#, no problems)
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Dec 6, 2011
I'm trying to add subs that will handle MouseOver events on textboxes that don't get created until after the program starts.
Each textbox gets created with a unique number attached to it like this...
AptTextBox0
AptTextBox1
AptTextBox2
etc...
Depending on how many are needed. But I never expect more than say... 15 at any given time.
Is it possible to handle MouseOver (or any events for that matter) if they don't exist until later.
I tried this but it didn't work....
I added this is the Designer code....
Friend WithEvents AptTextBox0 As System.Windows.Forms.TextBox
Friend WithEvents AptTextBox1 As System.Windows.Forms.TextBox
Friend WithEvents AptTextBox2 As System.Windows.Forms.TextBox
[Code]....
But it doesn't do anything. I don't get errors, but apparently it's still missing something to properly handle the events.
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Aug 19, 2010
Handle EventArgs on Variable or Not Yet Created Controls
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Dec 2, 2009
What's the C# equivalent of
<% dim name %>
so you can use it for web forms in PayPal API integration?
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Apr 20, 2011
Is there a way to define an implicit conversion operator in VB.NET?
I can't remember ever seeing or hearing of anyone do this; but now I'm in a situation where I think it would be incredibly useful to define my own custom 'type conversion' for my class.
As an example - let's say I have my own class, 'AwesomeDataManager'. It does not inherit from DataTable, but it holds data in a similar fashion to a DataTable. I would to be able to say, 'myDataTable = CType(MyAwesomeDataManager, DataTable)' and have it execute some code inside my class that would return a populated DataTable.
Granted, I could do something like 'MyAwesomeDataManager.GetDataTable' but for the sake of integrating with an existing code base, I'd like to avoid it.
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Jan 15, 2009
I created a Class which inherits Combobox and the listview is added . Now what I need is once the user click listview, the listview has to close and the clicked item has to added with combobox text. simply can say combobox1.text = listview.item(0).textFor closing & displaying the listview I need to handle the events. For
My Codings :========Public Class Combu_lstviewInherits ComboBoxPrivate treeViewHost As ToolStripControlHostPrivate Shadows dropdown As ToolStripDropDownPublic mylistview As New ListView
Public Sub New()mylistview.BorderStyle = BorderStyle.Nonemylistview.View = View.Detailsmylistview.HeaderStyle =
[code].....
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Dec 23, 2010
I am working on a new version of my clipboard manager. I was wondering if there would be a way to copy the value of a given handle without knowing its type? The current methods I know require one person to know the type of the handle (as an example by using Marshal.PtrToStructure).
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Sep 5, 2010
Using Visual Basic 2008 Express. I need to pass a variable to another form. Or else make the variable visible to both forms.
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Feb 23, 2011
I have written some C/C++ code that uses the winapi functions CreateFile WriteFile SetFilePointer etc. to read & write some large (>4 GB) binary files. Some colleagues who are more familier with Visual basic than C, want to modify some of their existing code to call my C code functions.
I have turned my code into DLLs that I have successfully called from other C programs. I have also created a small C DLL that doesn't use the winapi functions & called it from a small VB program.
What I haven't so far been unable to do is pass the HANDLE type variable between a C function that uses the winapi functions & the VB program that call it so the VB can call another of my functions & pass the HANDLE.
In my attempt to do this, the declarations in the header file for two of the functions in the C DLL are:
[Code]...
When I step through the VB code in debug mode there is no problem with calling OpenSegyRW, but at WriteToSegy I get the error message:System.Runtime.InteropServices.MarshalDirectiveException was unhandled
Message=PInvoke restriction: cannot return variants.So what am I doing wrong & is there any way to pass the winapi HANDLE type between VB & C code? BTW indents etc. get lost when I paste my message into the forum. I hope this is decipherable.
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Apr 11, 2012
Is there a way I can catch and handle two different exceptions within the same exception type? For example:
Try
' My code
Catch ex As System.Net.WebException
End Try
I have 2 different exceptions that are System.Net.WebException. I want to handle them different ways. Problem is the catch block above catches them both. Is there a way I can determine if which of the two it is and handle them differently?
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Sep 12, 2009
Say I have a button that creates more buttons with a random .Text property, and placed them on the form in different locations. And since these buttons are being created at runtime, I want to be able to have an event handler for all button controls on the form that makes the form's text the same as the sender's text.
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Apr 28, 2009
I have a panel with some controls in it (several textboxes, a slider, 2 buttons, and a small groupbox).. When I click a button, I want all of the textboxes within the panel to be readonly... So I have this code: [code] When I run it though, I get the following error:Unable to cast object of type 'System.Windows.Forms.Button' to type 'System.Windows.Forms.TextBox'.If I remove a button, it moves on to give me the same error but for a label..
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Jan 10, 2007
I was testing article [URL] to see if I could use this to populate a listview2 with the icons from Directory.GetFiles(apath) and getDirectories. If you go into c:windowssystem32 the program will hang for about 4 mins then if you go back to windows then back to system32 you will get the error.
win32 handle that was passed to icon is not valid or is the wrong type.
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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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Sep 24, 2009
I have added a button to my form from code because I'm linking a screen from other form, and in the linked form I've to add a back button. Now I success added a button in my form, but I cant handle the btnBack.Click
Dim btnBack As New Button
Dim y As Integer = 340
Dim x As Integer = 20
btnBack.Text = "Back"
[code].....
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Nov 9, 2009
I have given reference to Microsoft HTML in COM (am using VB 2008)
"Unable to cast object of type 'System.Windows.Forms.HtmlElement' to type 'mshtml.IHTMLElement'."
I want to retrieve all the properties like the class name, html id of every object in the web browser. I am getting the above exception when i try to direct cast it.[code]...
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May 17, 2009
I had created a form(MDI Child) which have 3 to 4 dataset on it. They all are loaded from the database at the form load event and therefore takes too much time to load and show some part of form during that time. When it load completely it shows the whole form. Is there any way that user will see the complete form instead of some broken form.
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Apr 9, 2009
I have 50 pictureboxes in one form. I need to write the same code for each one.one is to write a function for each PictureBox handling each object induvidually two is to write a function for all PictureBoxes that handle ALL object, but I have to declare each object in the Handles syntax of the subrutine as follows:
Private Sub PreviewTile(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles PB1.DoubleClick, PB2.DoubleClick, PBChapel.DoubleClick
DrawBorder(sender, Color.Wheat, 3)
[code]....
I was wondering if there is a way to write a subrutine that will Handle ALL Pictureboxes without having to enumerate them.example
Private Sub PreviewTile(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Me.PictureBoxes.DoubleClick '<-- made up
DrawBorder(sender, Color.Wheat, 3)
[code]....
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