去掉字符串中非法字符包括转义字符和全国字符

//非法字符自定义
private string Get_Format_Custorm(string str1)
{
string rel_str="";

// String str1 = "　　/r/n　　/r/n　　/r/n多幅阿斗所附斯多　　/r/n夫嘎的从";
String delim = "　/r/n ";//自定义去掉的字符
// String str2 = str1.Trim(delim.ToCharArray());
int startIndex=0;

while(startIndex<str1.Length)
{
str1 = str1.Trim(delim.ToCharArray());
int endIndex=str1.IndexOfAny(delim.ToCharArray(),startIndex);

if(endIndex!=-1)
{
rel_str+=str1.Substring(startIndex,endIndex-startIndex);
str1=str1.Substring(endIndex+1);

}
else
{
rel_str+=str1.Substring(startIndex);
break;
}
}
return rel_str;
}