Creating a method in which one of the parameters could be an array or a string

Question

I'm converting an old classic ASP method for data logging. One of the parameters could be an Array or a string. What type of variable do I declare? I tried declaring it as an object, and then testing the to see if it is an array. However, I cant seem to parse out the array contents (Should be a simple string array).

Here is a snippet of the classic ASP code:

               Public function security(u,a,d)
' -------------------------------------------------------
' Write to tbl_log_security, returning a 1-Pass or 0-Fail
' -------------------------------------------------------
    u = u + 0
    af = u
    if len(request.Cookies("userid")) > 0 then af = request.Cookies("userid")
    security =                                      1 ' Success
    Dim objCommandLog
    Set objCommandLog =                                Server.CreateObject("ADODB.Connection")   
    objCommandLog.open =                               application("connVRVprimary")
    Err.Clear
    if isarray(d) then
        for I = 0 to ubound(d)
            strDetails = strDetails &               chr(13) & "Detail " & I & ": " & d(i) & " "
        next
    elseif len(d) > 0 then : strDetails = d & " "
    end if

And here how I thought it might be converted to C#.

public static bool security(string UserID, string Action, object Details )
{ 
    // Apparently, Details can be a string or an array !
    // UserID is passed in as a string, we need to convert it to an int
    Int32 iUserID; //af
    string strDetails;

    if (!Int32.TryParse(UserID, out iUserID))
    {
        //If it doesn't convert, then use the UserID from Application Object
        iUserID = Convert.ToInt32(ApplicationObject.USERID);
    }

    Type valueType = Details.GetType();
    if (valueType.IsArray)
    {
    for(int i = 0, i < Details.Length; i++)
        {
            strDetails += "Detail " + i + ": " + Details(i);
        }
    }
    else
    { // is string
        strDetails = Details;
    }

Intellisense is telling me that I can't get the length property or iterate through it. I suspect that even thought it might come in as an array, it is treated as an object. Any help would be appreciated.

littlerufe · Accepted Answer · 2019-09-20 21:10:31Z

5

"One of the parameters could be an Array or a string. What type of variable do I declare?"

params to the rescue!

Since details is the last argument in the method signature, you can define it as a params argument, which allows any number of items to be passed.

(Side note: in C#, method names are typically PascalCase, and arguments are typically camelCase)

public static bool Security(string userID, string action, params string[] details )
{
    // Other code omitted for brevity

    var strDetails = details == null ? " " 
        : details.Length == 1 ? $"{details[0]} "
        : string.Join(Environment.NewLine,
            details.Select((detail, index) => $"Detail {index}: {detail} "));
}

edited Sep 20, 2019 at 21:10

answered Sep 20, 2019 at 20:35

littlerufe

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5 Comments

Alexei Levenkov Over a year ago

Since Ed's answer already covers it... maybe you should go for params instead?

littlerufe Over a year ago

Ah, when I first saw Ed's answer I didn't see the part about overloads! Thanks for the suggestion, @AlexeiLevenkov

pmcs Over a year ago

So I am basically writing two similar methods, one for string and one for array, and C# will treat it like an overload and match to the correct parameter signature ?

littlerufe Over a year ago

No, you only have to write this one method. It handles either a string or an array. The params keyword specifies that the argument can take in one or more values, and they can be passes as an array or as separate values from the caller, then they are captured into an array in the method. See the params documentation for more info.

15ee8f99-57ff-4f92-890c-b56153 Over a year ago

@RufusL I didn’t add the part about overloads until Alexei reminded me. Maybe Alexei should be getting all the internet points for both answers.

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