Performance Difference Between ToString() And & Concatenation?
Jun 1, 2010
When I am concatenating object values together to form a string in VB.NET, is there a difference in performance or a recommended best practice between using the & concat or the + concat with calls to .ToString() on each object?
Example (which is faster or best practice):
Dim result1 As String = 10 & "em"
Dim result2 As String = 10.ToString() + "em"
1. What's the difference between ToString and ToString()? (i do know that ToString method is to cast numeric values to string but don't know how to get it to work)
2. Why do i need XML comment feature? is it necessary?
I just want to know, what exactly the difference between the functions CStr() and Str() and also the .ToString()? With the code provided below, what's the difference between the three?
I am writing an application to gather, display and export system information for use with a Support Dept.Is there a performance difference between using WMI and My.Computer.X.X in VS 2005? Is one method better practice than the other?There are more lines with WMI, but am willing to write more if it's considered good practice over using My.Computer.X.X.
In VB.net, I tested concatenating 100k strings and found out one thread alone did it in 23 milliseconds. Two threads (each concatenating 50k) then joining the two at the end took 30 milliseconds. Performance wise, it didn't seem beneficial to utilize multiple threads when dealing with only 100k concatenations. Then I tried 3 million string concatenations and two threads each handling 1.5MM always demolished one thread handling all 3 million. I imagine at some point using 3 threads becomes beneficial, then 4, and so on. Is there a more efficient way to concatenate millions of strings in .NET?
Is there any difference between & and + operators while concatenating string?if yes, then what is difference? And if No, then why below code generating exception?
Example:
Dim s, s1, t As String Dim i As Integer s1 = "Hello"
I am wondering how to concatenate a string and an integer to form a button name.eg, ("button" & x) where x is an integer to form button1, button2, etc so i can change the backcolor of the buttons.
The below program throws a runtime error (invalid conversion from double) because there is [code]It compiles fine, but when the program is run, it throws a runtime error.Is this a compiler bug? Shouldn't it stop me with a compiler error, like invalid syntax ?
Possible Duplicate: The difference between + and & for joining strings in VB.Net.In VB.NET you can use either += or &= to concatenante a string (ignoring using a StringBuilder for this question -- this is directed at a very simple concatenation).
I'm trying to compose a String from multiple Strings, where some of the Strings may be in Arabic letters, the problem is that when I concatenate them, their order is being messed !!
For example, I have the following Strings:
Ref1 مسكه 2 Left
I want to concatenate them with the same previous order seperated by "-", but instead I get Ref1-مسكه-2-Left, as you can see, 2 is written before مسكه Does anyone know how to fix this problem, because it's really important in my case to have the exact same order, and I don't know where or when I might have these arabic strings, because it's being entered by User.
I have a windows form having combobox and textbox controls.. I have to generate a part number, consisting of combobox and textbox values included.. I can explain in detail.. This is the code i have used to define a variable "type"..
I'm trying to concatenate two properties into one string like so:
public class thing public property word() as string() public property count() as integer()
[Code]....
This is what I want, but it doesn't help that its in the debug output...I need to put it into a single string. I've tried using a_thing.count(i).tostring, but it doesnt work. If I look at the arrays individually, they have exactly the contents I want. But I can't concatenate them. Does it have something to do with suppressing the new line that debug.writeline usually creates?
I have combobox for year and combobox for month concatenated to make the date format "2012-01" My db field is RecordDate and is smallDateTime In my select statement im trying to use the left function to find match my concatenated string to the RecordDate field.Here is my code, hopefully someone can help me. Currently im getting the error "Conversion failed when converting date and/or time from character string."
Dim newRecordDate As String = (CStr(ComboBox2.SelectedValue)) & "-" & val1 Dim val10 As String = CStr(Convert.ToDateTime(newRecordDate)) Dim val21 As String = Microsoft.VisualBasic.Right(val10, 7) MsgBox(val10)
I've got a small app which I use to start a 3rd party application. When run from a shortcut the VB app starts the 3rd party app to and when loaded it displays its own file/folder interface, the VB app the closes itself. However, if you open a file in explorer associated with the 3rd party app, the 3rd party application loads and opens the file itself and not the file/open interface.
Uh OK, so what's the problem??The issue is I have changed the file extension associated with the 3rd party app to now use my VB app. I can successfully open files with the app from explorer if there are no spaces in the file or folder path however if there are, the 3rd party app opens and displays a File not found error message and gives the path up to the point where the space then follows.The relevant snippets of code from the app relating to the issue is below, specifically Dim Arguments variable where I am not quite sure how my string cocantenation should be to deal with the value of the variable 'Filename' which may or may not contain spaces.
I have no idea how to do this, but I want to create a [I dont know what it is called] to allow me to convert a class property to another type.The I could use the following w/ the new type:
Dim stringPhoneNo as String = "(111)111-1111" Dim typePhoneNo as PhoneNumber = stringPhoneNo.ToPhoneNumber()
When a custom class overrides the ToString() method, the C# IDE uses this function to display the class in the debug mode(tooltips, watcher etc) Does the VB.NET the same? I have impression that overriding ToString() method does change nothing. I mean, in the watcher I see Name myBusinessObjectInsnace Value {MyNamespace.myBusinessObjectInsnaceType}
If you try to compile the query below in Visual Basic .NET, it fails. From x In {1, 2} Select x.ToString() The error given by the compiler is: Range variable name cannot match the name of a member of the 'Object' class. There is nothing wrong with the equivalent C# query, though: from x in new[]{1, 2} select x.ToString()
This does not happen with the ToString overload that takes a format (it is a member of Int32, not Object). It does happen with other members of Object, as long as they don't take an argument: with GetType and GetHashCode it fails; with Equals(object) it compiles.
My problem is that I'm trying to parse a String to a System.Drawing.Color. Im trying to set up a simple notepad, here's part of my code:
Private Sub ToolStripMenuItem6_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Colorfuente2.Click Try Dim cdlg As New ColorDialog[code].....
Many times i was not getting correct output,then i put .tostring() at the end then it gave good output.so basically why do v need this?also Convert.ToInt32(cmd.ExecuteScalar()) why convert to int32?
Converting an object .tostring() removes the leading zeros. The object is not a fixed length, so I can't do object.tostring("0000000") where the number of zeros represents the fixed length.
An example object value is "0357" when I convert that object .tostring it becomes "357".
Is there a method for keeping the leading zeros where the length is not known?