VS 2008 A String Without A Value Was The Same As String
Jan 5, 2010
I'm writing some information to an SQL database in my program and I am using parameters with the SqlCommand class, thinking that this would take care of things like this for me but unfortunately it has not.
What I am doing is this: I create an instance of a class which has several properties, one of these properties is a String and in some cases there is no value assigned to this property,I then write the value of these properties to an SQL table.
what I was expecting was that if the value of this string property had not been set and I tried to get the value of it then I would just get String.Empty but it is actually returning Nothing.then when the SqlCommand comes to try and pass this in as a parameter it throws an exception stating that an expected parameter is missing.
This is how the property is defined:[code...]
I have managed to work around this by changing it so that the backing field is set to String.Empty when the class is initialised but I've never had to do anything like this before as far as I recall, I just thought that any String that had not had a value set would be String.Empty rather than Nothing. Am I just going mad or does anyone else think this is odd?
If I do this for example, I do indeed see the messagebox alert:[code...]
Also, I dont have the same problem with properties in this class that are Integers - if they are not set then I just end up with a 0 being written to the SQL table, which is what I want the string property to do (just write an empty string to the database if the property has not been set).
I'm guessing that is because Integers and other Value types have a default value (is it ALL value types that have a default value or just some?), but I thought Strings were made to behave pretty much in the same way with String.
I'm making a card game and the first thing I'm doing for it is generating a random card. I used an array for the cards (can't think of a better way to assign a picturebox to a card picture other then a huge select case block). I'm trying to split the 2D array into two parts but it doesn't work.
My current
vb Public Class frmMain Private Function Flop() 'First three common cards to be displayed.
[Code].....
I looked around online and I don't think a list will work for my 2-dimensional array.
I'm here again asking stupid questions. I don't have really get this but i ask again but i try explain all better. Here is a website link and i want catch string from here. Look page's source code and find first what starts <td> someword </td> I use this code for catch word from page. Visual Basic Express 2008
i have a string array that i want to output to a text file. the array size is 10000. i fill the array starting from 0 with some strings. at the end, i only want to show the array from index 256 to the last array that is not empty (for eg. if the array is filled with data from 0 to 2000, i only want the text file to show the data from 256 to 2000 and ignore the remaining strings). Is there any function to do this?t i use is shown below
Dim myArray(10000) as string Dim strArray As New System.IO.StreamWriter("c:List.txt") strArray.WriteLine("{0,10}{1,30}", "Index", "Symbol")
Im trying to work out what the best way to match 2 strings together, but with a difference.
String1 = "dog cat bird chair book table" String2 = "the dog chassed the cat around the chair"
No I know I can break string1 up by space character and check if each word appears in string 2, I would prefer to not have to do that.If there some sought of regex that would take a group of words and retrun how many of them matched ?
Currently, I'm using the following code to pull info from the management class.
[code]...
I'm also pulling info from the bios, disk drives, video, etc. What I've noticed, is although it runs fine on my pc, it may error out on some pcs since it is hardware dependent.I'm having trouble implementing a check to find if it exists before I convert to a string and add it to my overall string.
What would be the fasted method of get a string list of all values within [] in a string of text? For example: [client_name], are you are doing today? My name is [my_name]. The list of strings would be:
I want the Function to accept List(Of String), Array & String and similarly return List(Of String), Array & String respectively. The Function simply adds a string (month) to the input collection. I just want to use it for string, array and list with needing to think of conversions.
Basically I have a webresponse stream:dim lol as string = readstream.tostring there is a lot of information within the string but only one link starting with http: located near the end of the string - however there is no constant character point where I can start... (i.e. 38)
I want to extract the link from the string i.e. dog cat plane car [URL]..that is approximately how it looks above - words and url substituted I want to just extract [URL]..I had an idea of parsing the string from http: to the end Then after that splitting the string up again to remove the }], however it does not return anything
I got an app, which receives data via a R232 port, convert it to a string and on the other side I got a database, where the strings are saved. How can I find a way to compare the string with all strings in one database column and get back the another stringform the same row in this database. I never programmed a database
I have buttons generated through code (dynamically). I have to associate an event (the same) to them. I use AddHandler button.click, AddressOf mysub.The issue is that mysub gets a string (mysub(string)), but AddressOf doesn't accept a parameter inside the routine. How can I do this? Using also an alternative to AddressOf.
EDIT:
Public Class Form1 ... Private Sub mysub(ByVal sender As Object, ByVal e As System.EventArgs, ByVal str As String)[code]......
These is the content of my txt file which is saved in D drive in my pc abc,1,2,3..I tried the flowing but it didn't work:[code]I am getting error on this line.. data = line.Split(","c)...it says this line isn't in use anymore or something and that I rather use LineInput but thats asks for filenumber and i don't know what that is. I am sorry but I am a complete beginner. what else can I try? [code]ok that error is gone now but now if I want to add these values to a list box..how can i do that?
I have a field that I display via: String.Format({0:c},amount) This produces the string "$28.28" However, when I try to convert back to a decimal amount, I get an incorrect format exception: amount = Decimal.Parse(amount.Text, NumberStyles.Currency) I also tried it with NumberStyles.AllowCurrencySymbol with the same results. I verified that the value in amount.Text is "$28.28". Am I missing something? Shouldn't these two operations use the same currency symbol and formats?
I Ported this code from a code project article in c# called Nscript
heres the code
Base App Imports System Imports System.IO Imports System.Resources
[code]....
Okay Now I only get two errors (I dont know how to solve them)
Error3Class 'BaseApp' must implement 'Sub OnCompilerError(errors() As CompilerError)' for interface 'IScriptManagerCallback'.
And
Error4Class 'ScriptManager' must implement 'Sub CompileAndExecuteFile(file As String, args() As String, callback As IScriptManagerCallback)' for interface 'IScriptManager'.
But What I would also Like to know (as well as how to fix the errors), is would the code work?
Problem: Your task is to take input from the user in string and give the following options to the user in a menu.
1- Find a String 2- Create sub-string 3- Erase a portion of a sting 4- Replace a word in the string 5- Count number of words and characters in the string without spaces. 6- Capitalize first character of each new sentence and convert the rest of the characters to lower case. 7- Sort all the words in alphabetical order. (Use Bubble sort algorithm to perform sorting).
To perform all the above mentioned tasks you can only use pointers. Create a function to perform every task.
So strings are reference types right? My understanding is a reference to the string in the heap is passed even when you pass the string ByVal to a method.
Im working on a program and I get this "Value of type '1-dimensional array of String' cannot be converted to 'String'." heres the code that gets this error:
I don't understand why the line final.join etc pops up with these errors!! Value of type 'String' cannot be converted to '1-dimensional array of String' And Access of shared member, constant member, enum member or nested type through an instance; qualifying expression will not be evaluated This is my code.
when i transfer the bytes sent by the client program to a string the string length is affected.when i put the bytes sent by the client program to a message box. it returns the corrrect text. but when i check the length it will return 8192 or higher. but the actual size is just 5.
My Code
Dim tcpClient As TcpClient = tcpListener.AcceptTcpClient() RichTextBox1.Text = RichTextBox1.Text & vbNewLine & "Connection accepted." ' Get the stream[code]....
I'm trying to code a program but this error repeatedly shows up and I can't for the life of me figure it out EValue of type 'String' cannot be converted to 'System.Windows.Forms.TextBox'. It appears in relation to this code