string str = "dsds dsds sdsdgfhh380 dsdskds765dsd";
        Regex reg = new Regex(@"\d+");
        Response.Write(reg.Match(str));

------解决方案--------------------
Regex regex = new Regex("\d+");
var m = regex.Match("dsds dsds sdsdgfhh380 dsdskds765dsd");
if (m.Success)
 Console.WriteLine(m.Groups[0]);



------解决方案--------------------
探讨

Regex regex = new Regex("\d+");
var m = regex.Match("dsds dsds sdsdgfhh380 dsdskds765dsd");
if (m.Success)
  Console.WriteLine(m.Groups[0]);


------解决方案--------------------
js

document.write(("dsds dsds sdsdgfhh380 dsdskds765dsd").match(/(\d)+/)[0]);

------解决方案--------------------
Regex.Match("","\\d+").Value

------解决方案--------------------
探讨


C# code
        string str = "dsds dsds sdsdgfhh380 dsdskds765dsd";
        Regex reg = new Regex(@"\d+");
        Response.Write(reg.Match(str));