Replace non alphanumeric characters and multiple spaces with just 1 space

Question

I'm trying to replace all "non alphanumeric characters" and "multiple spaces" with just 1 single space

I have 2 working solutions, however i'm wondering if its possible to combine them efficiently?

Given

var str = "ASD S-DF 2134 4@# 4    234234 #$)(u SD";
var options = RegexOptions.None;

Solution for non alphanumeric characters

var rgxAlpha = new Regex("[^a-zA-Z0-9]");
str = rgxAlpha.Replace(str, " ", options);

Solution for multiple spaces

var regexSpace = new Regex(@"[ ]{2,}", options);
str = regexSpace.Replace(str, " ");

Expected Result

ASD S DF 2134 4 4 234234 u SD

Answer 1

Just the below would be enough, since [^a-zA-Z0-9]+ matches also the spaces, you don't need to add [ ]{2,} explicitly.

string result = Regex.Replace(str, @"[^a-zA-Z0-9]+", " ");

DEMO

Answer 2

Assuming they both work:

var rgxPattern = new Regex(@"[^a-zA-Z0-9]+|[ ]{2,}");

Just add a | between them.