Question

Hi
I have a general question about Lists in C#.
Here is my Code:

public List<string> Example()
    {
        ManagementObjectSearcher searcher = new ManagementObjectSearcher("root\\WMI", "SELECT * FROM MSStorageDriver_FailurePredictStatus");

        List<string> output = new List<string>();

        foreach (ManagementObject queryObj in searcher.Get())
        {
            output.Add(System.Convert.ToString(queryObj["InstanceName"]));
        }

        return output;
    }

and now I want to give the first input out

public FormMain()
    {

        Debug.WriteLine(Example(1));


    }

No overload for method ‘output’ takes 1 arguments

I hope you can explain me this and sorry for my question, I am an absoltue beginner

Best wishes

Answer 1

Well output is a List. Since you have coded Example as a method, which returns a list, to access it you need to call it using method syntax with empty parentheses. The return value is an instance of a List<string>. If you hit the decimal point after typing Example() you will see in intellisense the members of this object. One of them will show as square brackets like this []. this is the member you need to use to access whatever you have put in the list. The values you would provide are zero-based, that is they start at zero (for the first item in the list), and increase from there. So to access the first item in the list, you would write:

Debug.WriteLine(Example()[1]);

using the square brackets, not parentheses. You still need the parentheses in Example(), because it is a method… If you recoded it as a property:

public List<string> Example    
{     
   get 
   {   
      ManagementObjectSearcher searcher = 
        new ManagementObjectSearcher("root\\WMI", 
          "SELECT * FROM MSStorageDriver_FailurePredictStatus");        
      List<string> output = new List<string>();        
      foreach (ManagementObject queryObj in searcher.Get())
          output.Add(System.Convert.ToString(queryObj["InstanceName"]));  
      return output;
   }            
}

Then you would not need those parentheses and could just write

Debug.WriteLine(Example[1]);