How to tell if a string is a number in C #

String

2. Regular expression
   string regex = @^\d+$;
   
4. Write yourself a way: I wrote this.
   private bool Isnumber (string s)
   {
   int Flag = 0;
   Char[]str = S.tochararray ();
   for (int i = 0;i < str. Length; i++)
   {
   if (Char.isnumber (Str[i]))
   {
   flag++;
   }
   Else
   {
   Flag =-1;
   Break
   }
   }
   if (Flag > 0)
   {
   return true;
   }
   Else
   {
   return false;
   }
   }
   
6. Test
   private void Button1_Click (object sender, System.EventArgs e)
   {
   if (Isnumber (TextBox1.Text.Trim ()))
   {
   TextBox2.Text = is a number;
   }
   Else
   {
   TextBox2.Text = not a number;
   }
8. }
   
10. Try
    {
    Double. Parse (this. TextBox1.Text);
    Response.Write (is a number);
    }
    Catch
    {
    Response.Write (not numbers);
    }
    
12. Or you can use regular expressions:
14. Using System.Text.RegularExpressions;
    ------------------------
16. Regex r=new Regex (@^\d+ (\.)? \d*$);
    If R.ismatch (this. TextBox1.Text))
    {
    This. Response.Write (is a number);
    }
    Else
    {
    This. Response.Write (not numbers);
    }
    
18. public static bool Strisint (string Str)
    {
    Try
    {
    Int32.Parse (STR);
    return true;
    }
    Catch
    {
    BOOL flag = FALSE;
    return flag;
    }
    }
    
20. You should use regular expressions:
    String pattern = @^\d+ (\.\d)? $;
    if (Text1.Text.Trim ()!=)
    {
    if (! Regex.IsMatch (Sign_money. Text.trim (), pattern)
    {
    TEXT1 is not a number;
    }
    Else
    {
    Text1 is a number;
    }
    }