Compiler Assign Value To Variable Even Before It Is Actually Initiated?
May 10, 2011
I've just read [url]...
I'm wondering if it is a typo. Do they actually really wanted to say: the implementation of the JVM is free to instead of the compiler is free to.
and my second question is that do we have this issue with C#/VB as well? (in which the ""compiler"" is free to assign a value to a variable even before the variable is fully initiated/even before the constructor function of the class of the variable is fully ran.
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Jan 10, 2011
Say that i have the following code that parse about 20k records from the DB.
Code #1
vb.net While reader.Read()
list.Add(If(Integer.TryParse(reader(0).ToString, 0), Integer.Parse(reader(0).ToString), 0))
End While
And then another code which does the very same thing but it seems to be a little cleaner.
Code #2
vb.net While reader.Read()
Dim storeowner As Integer = 0
Integer.TryParse(reader(0).ToString, storeowner)
list.Add(storeowner)
End While
This is what i am confused about; does the compiler creates a new variable automatically when i use the if statement without strictly declared variable? What approach is better in sense of performance?
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Aug 24, 2010
Is there any way to know that a variable inside a method is Compiler generated.when decompiling a .net dll or exe the generated code looks like this. [code]
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Oct 20, 2011
I've read several articles and questions/answers that conclude the best practice is to let the JIT compiler do all the optimization for inline function calls. Makes sense. What about inline variable declarations? Does the compiler optimize these as well?
[Code]...
Of course I prefer the latter because it's easier to read and debug, but I can't afford the performance degradation if it exists. I have already identified this code as a bottleneck -- No need for retorts about premature optimization.
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Dec 8, 2010
How is conditional compilation controlled for a VisualBasic web? For a VB Windows app, I put a conditional variable in Project > Compiler tab > Advanced > Custom controls.
How in a VB web app is a conditional compilation variable assigned that can be accessed by all the files of the web app?
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Jun 29, 2010
I can make the compiler give me an error (Use of variable prior to assignment) with:
private sub Test()
Dim ord As Order
Dim ord2 As Order
[code].....
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Apr 27, 2011
I have a file txt file that holds 3 values each seperated by a space how can i assign each value to its own variable and use that for other things?
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Apr 2, 2010
I've been making this BlackJack program for a school project
I have 52 image files, labelled from '_1' to '_52' in my resources folder, each number corresponds to a card.
My question is, how do I get a picture box to assign the correct resource according to a variable
So, say I have
"pictDealerCard1" -> picture box which displays the first of the dealers card
DealerCard1 = 37 -> random number generated through INT(RND() * 52)
and resource '_37'
[Code].....
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Oct 12, 2009
I need to assign a varible in a while clause. I.e., i would do it in php like this: while (!is_bool($char=$this->getChar()) in every loop, the function would assign $char a value, the is_bool function would test it, and the code INSIDE the while clause would have access to that $char.
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Jul 18, 2012
i would like to assign the value of a combobox to a variable and use this variable as a parameter on the insert statement.see code below,code 1 works ok,but code 2 brings an error relating to wrong datatype,i cant seem to find where the problem because i think i am doing everything right.
[Code]......
i would like code 2 to work so that i can assign the variables different values at different scenarios. column serialno is a foreign key from table Stock.
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Mar 9, 2012
I want to assign a string value to a variable in the DataGridView LostFocus event. I found that I can't just do variable = "string value, it will give me the "Unable to cast object of type 'system.eventargs' to type 'system.windows.forms.datagridviewcelleventargs'" error.
The function created by double-clicking on the datagridview is:
Private Sub DataGridViewInvoice_LostFocus(ByVal sender As System.Object, ByVal e As System.Windows.Forms.DataGridViewCellEventArgs) Handles DataGridViewInvoice.LostFocus
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Jan 22, 2009
I'm trying to retrieve data from an access database, but I'm trying to do it all in VB. Basically I need to query the database, and I think I've done that correctly. But then I need to assign the value in a certain field, to a variable. So for example,
Dim email = orders.CustomerEmail.
How to assign a value to a variable.
Below is my current code:
Dim acc
As
New AccessDataSource()
accDS.SelectCommand = "SELECT TOP 1 orders.OrderDate, orders.OrderNumber, orders.OrderProduct, orders.OrderTotal, orders.CustomerName, orders.CustomerPostCode, orders.CustomerEmail"
accDS.DataFile = "~/App_Data/Database.mdb"
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Jan 23, 2010
I get nothing but headaches when I try to update settings in the My.Settings class, or when I try to assign a newly assigned setting to a variable. Sometimes the settings update OK at run time; other times times they update only after the application closes; and other times still they appear to update at run-time, then when I close the program and reopen- they go back to the previous settings.This is how I assign a value to a my settings and how I assign a setting value to a variable.[code]
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May 11, 2010
I'm new with vb.net my problem is how to assign field value from database to a variable here is my code
Call connectdatabase()
dim uname as string
dim pass as string
Try
sql = "SELECT * FROM user;"
command.Connection = conn
[Code] .....
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Jun 18, 2012
i like to assign html codes to String variable
Dim code As String
code= " <meta http-equiv="Content-Type" content="text/html; charset=windows-1254"> "
i think i am getting this error because of double Quotation marks "character constant must contain exactly one character."how can i assign it to a string?
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Jul 31, 2009
I would like to assign cboBegCust.SelectedValue to c and cboEndCust.SelectedValue to d
Dim c, d As String
cboBegCust.SelectedValue = "customer"
cboEndCust.SelectedValue = "customer"
[Code]....
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Nov 22, 2006
I want to Assign the Value to Multiple Variable of same type in .net and that to in one line of Code.
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Mar 31, 2009
I think I remember reading somewhere that it was possible to assign items to a variable if the item inherited from a base class, but I can't remember how.
I want to have a class that gets properties set and one of the properties is an error code property. I want to assign any exceptions that occur to the property, but it could be any type of exception. I remember that all exceptions inherit from the Exception class.
How can I assign an exception to a property based on the class it inherits from?
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Jun 1, 2011
I have the following
Public Structure Foo
dim i as integer
End Structure
[code].....
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Jul 28, 2010
is there any possibility to assign a value to a variable inside an IF condition in VB.NET?
Something like that:
Dim customer As Customer = Nothing
If IsNothing(customer = GetCustomer(id)) Then
Return False
End If
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Feb 16, 2011
Any way to attempt to assign a variable within a data class or structure when I have the variable name as a string. Where would this be useful? Let's say I have a data class that exactly mirrors the columns of a table in a SQL database. This lets programmers easily interact with table row data as it gets passed around as an actual, specific object since Intellisense can enumerate the variables for them, etc.
However, populating such an object is tedious and repetitive--the programmer who creates the new object has to one by one match up all the members when reading from the SQL data adapter. It would be nice if they could somehow enumerate all the variables in that class and attempt to auto-assign the values from the database instead of having to build a custom population method for each new data class. A person could create a hash table or tree or something that pairs member names with actual objects.
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Oct 28, 2010
I want to declare a variable to hold the query result from LINQ to SQL like to the following:
Dim query As IQueryable(Of Student)
If isNoUserName Then
query = From st In db.Students _
Order By st.AssignedId Ascending _
[code]....
Return query
Error : conversions from 'System.Linq.IQueryable(Of )' to 'System.Linq.IQueryable(Of Student)'.
How do I declare variable "query" to hold both data from "Student" and "User" tables?
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May 15, 2010
Is it possible to declare a variable and to choose it's appropriate type during runtime?
it should be something like this (of course, the last line does not work):
'Determine what type of variable is needed later
Dim myVariableType As System.Type = System.Type.GetType("System.String", True, True)
'Create variable with needed type
Dim myVariable As myVariableType ' Should be a string variable in this case
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Apr 24, 2011
How do I assign the query result to a variable.I am using SQLlite. Below is the code for retrieving password from the User Table. I need to compare the given password and the given password.
Dim i As String
Dim p As String
i = txtUserID.Text
[code].....
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Apr 26, 2011
So I have a class called Transactions and I put all my functions there. The problem is, when I try to call that specific function and assign it to a variable, there is a "ByRef Argument Type mismatch" error that keeps on bugging me.
Public Function GetUserID(name As String) As Integer
Dim gotID As Integer
Dim rec As Recordset
Call connectDB
sSQL = "select ID from User where Name ='" & name & "'"
Set rec = CurrentDb.OpenRecordset(sSQL)
[Code] ......
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Mar 28, 2010
Dim n As System.Windows.Forms.TreeNode
For x = 1 To TreeView1.GetNodeCount(True)
n = TreeView1.Nodes.Item(x)
[code]....
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Mar 30, 2012
On Combobox how do I assign variable to those stings?
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Apr 12, 2011
Is it possible to assign a pixel value of a binary file to infinity? Lets say that my binary file is composed of 4 pixels only and the values are (1, 4, 8, &)... Would it be possible to assign the fourth pixel to infinity?
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Sep 25, 2009
which compiler errors would be detected out by VB compiler?
I have searched out some compiler errors list for C#, for example, see the website at [URL]
MS provided us the information about C# compiler error. Does MS provide VB compiler errors information as well.VS
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Nov 2, 2010
I have been searching the internet trying to understand in its simplist form why this behavior happens.
Dim mysingle As Single = 456.11 Dim mybool As Boolean = mysingle = 456.11
In the lines above mybool becomes false. I found this behavior when putting the single into a double I found extra digits showing. The .net documentations states a single is an approimate value I gatehr a single is a 32bit floating point number? But why are extra digits appearing when I have explicitly said what the number is.. surely the memory should store that numbers either side of my number are 0 to fill up the memory location?
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