The following is the.net Framework 3.5 created in method in a class library file:

 
///& lt; Summary> 
///converted to string type string 
///& lt;/summary> 
///& lt; Param name="s" & gt; Access to need to transform the value & lt;/param> 
///& lt; Param name="format" & gt; Need to format the digits & lt;/param> 
///& lt; Returns> Returns a new string & lt;/returns> 
Public static string ToStr (this object s, string format="") 
{
string result=""; 
Try 
{
If (the format=="") 
{
Result=s.T oString (); 
} 
The else 
{
Result=the string. Format (" {0: "+ Format +"} ", s); 
} 
} 
Catch 
{
} 
return result; 
} 

When the above class library files are imported into the.net Framework 4.5 web App_Code folder of the project, in the class library file to call its methods are as follows:

 
Public static string GetRequestStr (this object c, string key, bool filterSQL=true) 
{
[key] string textValue=https://bbs.csdn.net/topics/HttpContext.Current.Request ToStr (" ");//there is a problem here 
If (filterSQL & amp; & TextValue. The Trim ()!="") 
{
TextValue=(https://bbs.csdn.net/topics/textValue.filterSQL);//a string of verification, determine whether contain special characters or keyword, if contain special characters processing, 
} 
Return textValue; 
} 

Page prompts questions as follows:
CS0121: The call is ambiguous between The following methods or properties: 'UserUtility. Utility. ToStr (object, string)' and 'UserUtility. Utility. ToStr (object, string)'