Hi @sravankumar-3852,
Regular expressions can be written like this:
var pattern = "^[a-zA-Z0-9]\\S+$";
Below is the demo I tested, you can refer to it.
class Program
{
static void Main(string[] args)
{
var pattern = "^[a-zA-Z0-9]\\S+$";
Console.WriteLine("Invalid scenarios:");
Console.WriteLine("!test:{0}", Regex.Match("!test", pattern).Success);
Console.WriteLine("@Test:{0}", Regex.Match("@Test", pattern).Success);
Console.WriteLine(" Test:{0}", Regex.Match(" Test", pattern).Success);
Console.WriteLine("\n\nValid scenarios:");
Console.WriteLine("Test@3:{0}", Regex.Match("Test@3", pattern).Success);
Console.WriteLine("test!12a:{0}", Regex.Match("test!12a", pattern).Success);
Console.WriteLine("7test#1:{0}", Regex.Match("7test#1", pattern).Success);
Console.WriteLine("67899:{0}", Regex.Match("67899", pattern).Success);
Console.WriteLine("Test:{0}", Regex.Match("Test", pattern).Success);
Console.ReadLine();
}
}
Here is the result.
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Best Regards,
YihuiSun