IS Numeric

[Tamer_Ahmed]

hi in VB.net i can use ISNumeric to determine if it's numeric or not but in C# i can't use it can any body help

[PlausiblyDamp]

You could use regular expressions to validate the string (search these forums and you'll will find a few samples), or alternatively you may want to use the double.TryParse(...) method - incidently if you look at the VB IsNumeric function in ildasm then it actually calls the TryParse method itself anyway....

[Jaco]

Something like:

 

internal static double IsNumeric(object oValue)

{

try

{

if (oValue == null || System.Convert.IsDBNull(oValue))

return false;

 

string sString = oValue.ToString().Trim();

 

double dValue=0;

if (double.TryParse(sString, NumberStyles.Any,

CultureInfo.CurrentCulture, out dValue))

return true;

else

return false;

}

catch

{

return false;

}

}

[Mister E]

Just reference Microsoft.VisualBasic and you can use the VB IsNumeric function in C#.

 

Otherwise, just do something like this:

private bool IsNumeric(object o)
{
   try { double d = Convert.ToDouble(o); return true; }
   catch { return false; }
}

[Joe Mamma]

Just reference Microsoft.VisualBasic and you can use the VB IsNumeric function in C#.

[/Quote]BOO!!!! Bad Vb'er Bad!!!

[Mister E]

It works, and it really doesn't matter since it's all compiled into the same runtime anyway.

[jspencer]

hi in VB.net i can use ISNumeric to determine if it's numeric or not but in C# i can't use it can any body help

 

Try this out Tamer:

 

   Public Overloads Function IsNumeric(ByVal Value As Object) As Boolean
       Dim RegEx As Regex

           If Not Value Is Nothing Then
               RegEx = New Regex("(\+|-)?[0-9][0-9]*(\.[0-9]*)?")
               If RegEx.IsMatch(Value.ToString) AndAlso RegEx.Match(Value.ToString).Length = CType(Value, String).Length Then
                   Return True
               Else
                   Return False
               End If
           Else
               Return False
           End If

 End Function

 

You should be able to easily convert this to c#.

[PlausiblyDamp]

Although the regex works it does have a locale bias (assumes .) as decimal seperator, and will fail if a thousands seperator is specified (or if a trailing +/- is used).

Also it will not cope with currency or non decimal (e.g. hex) numbers.

 

Using double.TryParse like I suggested an Jaco showed how to do in a previous post in this thread is a easy enough way to do this.