Visual Basic

7-Oct-09 5:58

Hey, I'm a very beginner so please don't laugh Wink | ;-)

I want to validate a date user inputs:

Dim scr_time As Date
dim ok as boolean


System.Console.WriteLine("Enter screening date & time [DD/MM/YYYY HH/MM]")
        scr_time = System.Console.ReadLine()

        ValidateDate(scr_time, ok)



Sub ValidateDate(ByVal scr_time As String, ByRef bol_isvalid As Boolean)
        If IsDate(scr_time) Then
            bol_isvalid = True
        Else
            bol_isvalid = False
        End If
    End Sub

When entered 'notdate' the error says "Conversion from string "notdate" to type 'Date' is not valid."

Is that because I declared scr_time as date, instead of string? If I declare the date as string is

now >= scr_date

going to work fine?

Second question regarding validation of number:

Dim cnt_adult As Integer

System.Console.WriteLine("How many adult tickets required?")
        cnt_adult = System.Console.ReadLine()

        ValidateNumber(cnt_adult, ok)

        If ok Then
            System.Console.WriteLine()
        Else
            System.Console.WriteLine("Incorrect value. Press any key to try again.")
            System.Console.ReadKey()
            GoTo sale
        End If


Sub ValidateNumber(ByVal text As String, ByRef bol_isvalid As Boolean)
        If IsNumeric(text) Then
            bol_isvalid = True
        Else
            bol_isvalid = False
        End If
    End Sub

"Conversion from string "t" to type 'Integer' is not valid."

I know the solution would be to declare the variable cnt_adult as string, by I need it as integer so I can multiply it with another integer later.

modified on Wednesday, October 7, 2009 3:41 PM

EliottA7-Oct-09 6:08

7-Oct-09 6:08

Use the TryCatch structured error handling, it will help you wonders, or you can also use Int32.TryParse[^] to convert a string to a numeric.

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Frauenarzt7-Oct-09 6:27

7-Oct-09 6:27

I don't want to convert entered by user letters to equivalent numbers, I just want program to make sure the user inputs only numbers where asked, if he enters anything else I will ask him to enter it untill its numbers only [loop].

Henry Minute7-Oct-09 7:18

7-Oct-09 7:18

If you read the documentation for ReadLine you will see that the very first line states:

Reads the next line of characters from the standard input stream.

**NOTE** it says characters. Not numbers. Not hieroglyphics. Characters.

Therefore you will have to use int.TryParse and DateTime.TryParse (the last of these will fail incidentally given your code. Use HH:MM not HH/MM) to get the data into the form that you want.

Henry Minute

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Frauenarzt7-Oct-09 7:32

7-Oct-09 7:32

Actually characters include numbers.

Henry Minute7-Oct-09 7:38

Re: Validation of the date and number [modified]

7-Oct-09 7:38

Well since you obviously already know everything, why did you ask for help?

Frauenarzt7-Oct-09 7:47

7-Oct-09 7:47

I don't know everything, furthermore I know much less than you regarding this topic, however I'm certain that the numbers are characters and ReadLine reads them.

dim int_number as integer

System.Console.WriteLine("Enter number")
int_number = System.Console.ReadLine()

System.Console.WriteLine(int_number)

Examples of characters include letters, numerical digits, and common punctuation marks (such as '.' or '-'). from wikipedia.org

btw. I respect your knowledge [as seen on your profile] but what you said was mistake, wasn't it?

Or maybe I'm wrong, or didn't understand you quiet well, then explain me please.

Thank you for your time.

added:

oh, I understand now what's the misunderstanding. "characters" can refer to a letters only or a group of signs incl. letters, numbers, punctuation marks. So the meaning of a character in this quote "Reads the next line of characters from the standard input stream." is general [character may be a letter or a number ect]

modified on Wednesday, October 7, 2009 2:12 PM

Henry Minute7-Oct-09 8:33

Re: Validation of the date and number [modified]

7-Oct-09 8:33

Yup your 'added:' is correct.

Readline() reads a series of characters and returns them as a String. Your code works because, behind the scenes, the VB compiler 'sees' that you want an int and does the casting for you. Just to confirm this for your own satisfaction, run the code and enter '22f', after a bit you should get an exception message saying 'The cast from string to int was unsuccessful.', or similar. Now you haven't done any casting, so it must have been done for you. (FYI: your code won't even compile in C#. Another reason not to do it this way, just in case you have to change language for some reason. Smile | :)

)
In C# your code is almost identical:

int int_number = 0;

System.Console.WriteLine("Enter number");
int_number = System.Console.ReadLine(); // <============= COMPILER FAILS HERE 'Cannot convert String to Int'

System.Console.WriteLine(int_number);

Anyway, if you always treat the value from a ReadLine() as a string, you won't get any run-time errors, regardless of what the user enters. You can then attempt the conversion yourself, in a way that you can control. Using the TryParse() methods of the various Types is about the most easily controlled way of doing it.

Frauenarzt7-Oct-09 9:18

7-Oct-09 9:18

Thank you very much Smile | :)

I tried to make a use of it:

dim cnt_adult as integer
Dim ok As Boolean
Dim result As Integer


System.Console.WriteLine("How many adult tickets required?")
cnt_adult = System.Console.ReadLine()

ok = Integer.TryParse(cnt_adult, result)

The compiler breaks on ReadLine() when I type in any letter, and that's obvious because cnt_adult is declared as integer, instead string.

The things is I need cnt_adult to be an integer, so I can multiply/add that value later on. [If I try add two values [for example 2 and 4] as strings the result will be "24" not "6".

Do you have any suggestions?

added:

I think I found an answer. I can declare cnt_adult as string and then easily validate it and when I will use it as integer just type:

cInt(cnt_adult)

Thank you once again for help Smile | :)

modified on Wednesday, October 7, 2009 3:25 PM

EliottA7-Oct-09 9:22

7-Oct-09 9:22

Declare cnt_adult as string, and then do
ok = Integer.TryParse(cnt_adult)

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Ian Shlasko7-Oct-09 9:38

Ian Shlasko

7-Oct-09 9:38

Use a temporary string to read the input.

Dim userInput as String
Dim isValid as Boolean
Dim cnt_adult as Integer

'... Prompt for input ...

userInput = System.Console.ReadLine()

isValid = Integer.TryParse(userInput, cnt_adult) 
'cnt_adult now contains the numeric value IF it was valid

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Developer, Author (Guardians of Xen)

Henry Minute7-Oct-09 10:21

Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 10:21

I see that others have already replied but here's my effort anyway:

Dim cnt_adult As Integer
Dim userInput As String
Dim ok As Boolean

ok = False
While (ok = False)
    System.Console.WriteLine("How many adult tickets required?")
    userInput = System.Console.ReadLine()
    ok = Integer.TryParse(userInput, cnt_adult)
End While

Sorry for not replying earlier, but I was in the middle of a very, very important game. Laugh | :laugh:

Garth Geoghan7-Oct-09 5:08

Re: Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 5:08

When I try to make a connection to the db from VB I get this error message.

"A network-related or instance-specific error occurred while establishing a connection to SQL Server. The server was not found or was not accessible. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified)"

I'm am using the default named instance.

The connection works just fine with the SQL Server Management Studio and the configuration manager. I've done two days of searching and trying various items that I've found but nothing seems to work.
Any help would be most appreciated.

EliottA7-Oct-09 5:11

Re: Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 5:11

Any chance we can see your connection string?

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Garth Geoghan7-Oct-09 5:33

Re: Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 5:33

Thanks Elliot,

This is the connection string from the machine.config file in the C:\WINDOWS\Microsoft.net\framework\v2.0.50727\CONFIG file.

<add name="LocalSqlServer" connectionstring="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|GGTEST.mdf;User Instance=true" providername="System.Data.SqlClient">;

Garth

Garth Geoghan7-Oct-09 7:12

Re: Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 7:12

Eliott,

I see that my post had the actual text of the conn string stripped out. Here it is.

http://kb.discountasp.net/article.aspx?id=10413[^]

EliottA7-Oct-09 7:19

Re: Connecting VB2008 Express to SQL Server 2008 Developer

7-Oct-09 7:19

The link you sent wrote:
Server Error in '/' Application.

The resource cannot be found.

Description: HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable. Please review the following URL and make sure that it is spelled correctly.

Requested URL: /article.aspx

Version Information: Microsoft .NET Framework Version:2.0.50727.3074; ASP.NET Version:2.0.50727.3074

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Garth Geoghan7-Oct-09 7:23