S. Srinivasa Sivakumar's Blog World

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C# Tips

I've always loved VB for its simplicity. When a VB programmer moves to C#/.NET he misses those VB functions that helped him a lot. I wrote few functions to mimic those good old VB functions in C#.

1. Porting Common VB functions to C#: isNumeric()

bool isNumeric(char ch)
{
    //If the given character is in between 0 and 9 then
    //return true, otherwise false
    if (ch >= '0' && ch <= '9')
        return true;
    else
        return false;
}
 

2. Porting Common VB functions to C#: Asc()

int Asc(char ch)
{
    //Return the character value of the given character
    return (int)Encoding.ASCII.GetBytes(S)[0];
}
 
3. Porting Common VB functions to C#: Chr()

Char Chr(int i)
{
    //Return the character of the given character value
    return Convert.ToChar(i);
}
 
4. Porting Common functions to C#: isLower()

bool isLower(char ch)
{
    //If the given character is in between a and z then
    //return true, otherwise false
    if (ch >= 'a' && ch <= 'z')
        return true;
    else
        return false;
}

The same function can also be written as more .NET frieldly:

bool isLower(char ch)
{
    return Char.IsLower(ch));
}
 
5. Porting Common functions to C#: isUpper()

bool isUpper(char ch)
{
    //If the given character is in between A and Z then
    //return true, otherwise false
    if (ch >= 'A' && ch <= 'Z')
        return true;
    else
        return false;
}

The same function can also be written as:

bool isUpper(char ch)
{
    return Char.IsUpper(ch));
}

Posted: Sep 17 2003, 07:48 PM by SrinivasaSivakumar@India.com | with 25 comment(s)

Comments

Raymond Chen said:

Beware that most of these functions have a very narrow world view. For example, your isLower doesn't work in Europe since it completely misses lowercase accented letters. (Even some English words contain accented letters, such as "naïve" - surely this word is lowercase, isn't it?) And Indic languages have numerals that look different from "0" through "9". Char.IsLower, Char.IsUpper, and Char.IsDigit and/or Char.IsNumeric are preferred here.
# September 17, 2003 10:31 AM

James Avery said:

You might just want to use the VisualBasic namespace, it includes alot of functions like this. (And it is written in C# anway, so there is no harm in using it)

Also, you can use reflector to check out how they wrote these functions, etc.

-James
# September 17, 2003 11:02 AM

Cadmium said:

Aren't most, if not all of these vb functions still available to C# through the vb.net namespaces?
# September 17, 2003 11:03 AM

OmegaSupreme said:

I have to say theres very little I miss about vb ;) but thanks for the functions, they may come in handy.

You could use the visualbasic namespace but its useful to have them in pure c# also because one day you may port your code to a none microsoft implementation, unlikely but you never know.
# September 17, 2003 11:19 AM

Dave Rothgery said:

Just as an FYI -- the Microsoft.VisualBasic namespace is written in VB.NET, at least according to Paul Vick, who ought to know.
# September 17, 2003 12:23 PM

Jeff Gonzalez said:

The IsNumeric function is very narrow, why not just use something like Anakrino to decompile the functionality you miss into a seperate utility dll.
# September 17, 2003 5:52 PM

TrackBack said:

# January 4, 2004 10:01 PM

JackNet (ASP.NET) said:

Thanks your functions, helps solve my problem:

I have a little bit change to your IsNumeric(), please give some advice.

public static bool IsNumeric(string words)
{
char[] chs = words.ToCharArray();

foreach (char ch in chs)
{
// If the given character is in between 0 and 9 then
// return true, otherwise false.
if (ch >= '0' && ch <= '9')
continue;
else
return false;
}
return true;
}
# April 5, 2004 3:19 AM

Phillip Jacobs said:

You are only checking if a single character is numeric. In that case you can use Char.IsNumber(ch) and it will work exactly as you want.

That is not equivalent to the Microsoft.VisualBasic.Information.IsNumeric(string) function which checks any number such as -100, 100, and 100.00 and reports them correctly.

There is a very good discussion on this topic at http://www.tulsadnug.org/DesktopDefault.aspx?tabid=23&frmView=ShowPost&PostID=624
# June 1, 2004 9:56 PM

TrackBack said:

# June 3, 2004 1:13 AM

TrackBack said:

# June 3, 2004 1:16 AM

Todd Moon said:

Your isNumeric method could be better written with a regular expression, such as:

private bool isNumeric(string subject)
{
return(System.Text.RegularExpressions.Regex.IsMatch(subject,"^[-0-9]*.[.0-9].[0-9]*$"));
}

This works with any string, negative numbers, decimals, etc.
# June 30, 2004 5:37 PM

Jayce Ooi said:

Thanks man. Your guide helps me a lot. :)

# August 10, 2007 1:51 AM

Stiven Fabiano da Câmara said:

       public static string ValidateAlfaNumeric(string value)

       {

           char[] chars = value.ToCharArray();

           List<char> charValid = new List<char>();

           foreach (char ch in chars)

           {

               if ((ch >= '0' && ch <= '9') || (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z'))

                   charValid.Add(ch);

           }

           string aux = string.Empty;

           foreach (char ch in charValid)

               aux += ch.ToString();

           return aux;

       }

# August 17, 2007 9:11 PM

Sri said:

Thank you.  You helped me

# September 27, 2007 9:42 AM

Britney said:

Cool beans, you saved me an afternoon of headaches.

# April 29, 2008 12:17 PM

Ofir said:

hi! i have got a problem with char... i need the Aski value of a char but u dont know the syntex so if any one can write it?....

# August 17, 2008 5:05 AM

ForeignTrade said:

ofir, see "Porting Common VB functions to C#: Asc()"

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