Use of IsNumeric function in VB.NET
IsNumeric() function returns a value indicating whether an expression can be converted to a numeric data type.
IsNumeric() function returns True if the data type of Expression is Boolean, Byte, Decimal, etc or an Object that contains one of those numeric types, It returns a value indicating whether an expression can be converted to a numeric data type. It also returns True if Expression is a Char or String that can be successfully converted to a number.
IsNumeric returns False if Expression is of data type Date or of data type Object and it does not contain a numeric type, It has to do with the format/type of the data, not the actual value of the data. And "NaN" I believe is technically of type float. IsNumeric returns False if Expression is aChar or String that cannot be converted to a number.
Example:
Public Class Sample
Public Shared Sub Main()
Dim Data1 As String = Nothing
Dim Output As New System.Text.StringBuilder
Output.AppendLine(String.Format( _
"IsNumeric({0}) ... {1}", Data1, IsNumeric(Data1)))
Output.AppendLine()
Data1 = "-11.1231"
Output.AppendLine(String.Format( _
"IsNumeric({0}) ... {1}", Data1, IsNumeric(Data1)))
Output.AppendLine()
Data1 = "October 21, 1987"
Output.Append(String.Format( _
"IsNumeric({0}) ... {1}", Data1, IsNothing(Data1)))
Console.WriteLine(Output.ToString())
Console.ReadLine()
End Sub
End Class
Output:
