改善现有代码段所需的帮助

Question

I have written a code snippet which i definitely feel its not written a correct way. My method must return a string based on the version of the Adobe Installed in my machine.

private string GetRegistryKeyPathForX()
        {
            string sPath = string.Empty;
            RegistryKey adobe = Registry.CurrentUser.OpenSubKey("Software").OpenSubKey("Adobe");
            if (adobe != null)
            {
                RegistryKey acroRead = adobe.OpenSubKey("Adobe Acrobat");
                if (acroRead != null)
                {
                    string[] acroReadVersions = acroRead.GetSubKeyNames();
                    //The following version(s) of Acrobat Reader are installed
                    foreach (string versionNumber in acroReadVersions)
                    {
                        switch(versionNumber)
                        {
                            case "6.0": sPath = "Software\\Adobe\\Acrobat Reader";
                                        return sPath;  //Improve here
                                        break;

                            case "7.0":
                                        sPath = "";
                                        return sPath;   //Improve here
                                        break;
                            case "8.0": 
                                        sPath = "";
                                        return sPath;   //Improve here
                                        break;
                            case "9.0" :
                                        sPath = "Software\\Adobe\\Acrobat Reader";
                                        return sPath;   //Improve here
                                        break;
                            default: sPath = "ERR_KEY";
                                            break;
                        }  
                    }
                }
            }
        return sPath;
    }

Is there a way so that i can return the string in one shot instead of assigning it in each case statement.?

Answer 1

If you just optimize the switch, you could write:

switch(versionNumber)
{
   case "6.0": 
   case "9.0": 
      return "Software\\Adobe\\Acrobat Reader";
  case "7.0":
  case "8.0": 
      return string.Empty;
  default: 
      return "ERR_KEY";
}

However, I prefer using maps instead of switches (especially if you need this logic in more than one place), so you could do:

Dictionary<string, string> versionPaths = new Dictionary<string, string>();
versionPaths.Add("6.0","Software\\Adobe\\Acrobat Reader");
versionPaths.Add("7.0",string.empty);
....
if (versionPaths.ContainsKey(versionNumber))
  return versionPaths[versionNumber];
else
  return "ERR_KEY";

Answer 2

Yes: you don't need either the assignment or the break statement:

case "6.0": return "Software\\Adobe\\Acrobat Reader";

If you can get a copy of ReSharper it can really help with this sort of thing: in this case, it would highlight the unused code break statement in grey, and it would offer to automatically remove the assignment.

Answer 3

No need to write break; since it is returning values from there

switch(versionNumber)
 {
     case "6.0": return "Software\\Adobe\\Acrobat Reader";  
     .
     .
     .
 }

OR return after switch statement

switch(versionNumber)
 {
     case "6.0": sPath = "Software\\Adobe\\Acrobat Reader";          
         break;
     .
     .
     .
 }
 return sPath;

Answer 4

You can replace the loop and the switch with this:

if (acroRead.GetSubKeyNames().ToList().FindAll(versionNumber => versionNumber.Equals("6.0") || versionNumber.Equals("9.0")).Count > 0)
   return "Software\\Adobe\\Acrobat Reader";

Edit: .NET 2 version:

if (Array.FindAll<string>(acroRead.GetSubKeyNames(), delegate(string versionNumber) { return versionNumber.Equals("6.0") || versionNumber.Equals("9.0"); }).Length > 0)

Answer 5

private string GetRegistryKeyPathForX()
{
    var adobe = Registry.CurrentUser.OpenSubKey("Software").OpenSubKey("Adobe");
    if (adobe == null)
    {
        return string.Empty;
    }

    RegistryKey acroRead = adobe.OpenSubKey("Adobe Acrobat");
    if (acroRead == null)
    {
        return string.Empty;
    }

    string[] acroReadVersions = acroRead.GetSubKeyNames();

    //The following version(s) of Acrobat Reader are installed
    foreach (string versionNumber in acroReadVersions)
    {
        switch (versionNumber)
        {
            case "6.0": return "Software\\Adobe\\Acrobat Reader";
            case "7.0": return "";
            case "8.0": return "";
            case "9.0": return "Software\\Adobe\\Acrobat Reader";
            default:    break;
        }
    }

    return "ERR_KEY";
}