你必须使用Regex作为\d+

\d匹配给定字符串中的数字。

  string verificationCode ="dmdsnjds5344gfgk65585";
            string code = "";
            Regex r1 = new Regex("\\d+");
          Match m1 = r1.Match(verificationCode);
           while (m1.Success)
            {
                code += m1.Value;
                m1 = m1.NextMatch();
            }

var match=Regex.Match(@"a99b",@"\d+");
if(match.Success)
{
    int val;
    if(int.TryParse(match.Value,out val))
    {
        //val is set
    }
}

对于那些想要十进制数字的字符串与Regex在两行:

decimal result = 0;
decimal.TryParse(Regex.Match(s, @"\d+").Value, out result);

同样的事情也适用于float, long等等…

以下是我如何清理电话号码，让它只有数字:

string numericPhone = new String(phone.Where(Char.IsDigit).ToArray());

static string GetdigitFromString(string str)
    {
        char[] refArray = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
        char[] inputArray = str.ToCharArray();
        string ext = string.Empty;
        foreach (char item in inputArray)
        {
            if (refArray.Contains(item))
            {
                ext += item.ToString();
            }
        }
        return ext;
    }