C HTML character conversion function sharing

Therefore, the following functions are required for conversion:

 
///<summary> 
/// replace html Special characters in  
///</summary> 
///<paramname="theString"> The text that needs to be replaced. </param> 
///<returns> Replace the finished text. </returns> 
public static string HtmlEncode(string theString) 
{ 
theString=theString.Replace(">",">"); 
theString=theString.Replace("<","<"); 
theString=theString.Replace(" "," "); 
theString=theString.Replace("\"","""); 
theString = theString.Replace("\'", "'"); 
theString=theString.Replace("\n","<br/>"); 
return theString; 
} 

///<summary> 
/// restore html Special characters in  
///</summary> 
///<paramname="theString"> Text that needs to be recovered. </param> 
///<returns> Restore good text. </returns> 
public static string HtmlDiscode(string theString) 
{ 
theString=theString.Replace(">",">"); 
theString=theString.Replace("<","<"); 
theString=theString.Replace(" "," "); 
theString=theString.Replace(""","\""); 
theString = theString.Replace("'", "\'"); 
theString=theString.Replace("<br/>","\n"); 
return theString; 
}