通过转换为字符串将数据转换为数组

Question

I have a dataset with one datatable, one row and six columns:

DataSet holdall = new DataSet();

            holdone.Fill(holdall);

            DataTable invoiceTable = holdall.Tables["INVOICE"];

The data comes from an SQL database, and consists of several different data types. I need to pass this data into an array or a list (AFAIK An array is more appropriate), and on the way convert it into string format:

string[] currentInvoice = new string[6];
currentInvoice = invoiceTable.AsEnumerable().Take(1).ToString().ToArray();

This gives me the following error:

Cannot implicitly convert type 'char[]' to 'string[]'

I have also tried

foreach (DataRow INVOICE in invoiceTable.AsEnumerable())
            {
                currentInvoice.ToArray();
            }

However, this returns a Null exception, that leads be to believe that there is no data in the datatable. Upon examining the datatable via a stop point, I find that there is the correct amount of data.

Am I overcomplicating this?

Answer 1

When you call .ToString() you're converting whatever that is to a single string . Calling .ToArray() on a single string doesn't split that string into any meaningful substrings, it just converts it to a char[] , which as the error states is incompatible with the variable type string[] .

So, if I understand correctly... You have a table, of which you want only the first row, and you want the items in that row to be strings in an array? Something like this ought to work:

currentInvoice = invoiceTable.AsEnumerable().First().ItemArray.Select(i => i.ToString()).ToArray();

It takes the table as an enumerable, grabs the first row, looks at the array of items in that row, converts each item to a string , and converts that enumeration of string s into an array.

Edit: Note the use of .First() instead of .Take(1) . While conceptually they do the same thing, .Take() returns a collection of items (even if there's only one item in the collection) whereas .First() returns only a single item. Note also that these could throw errors if there are no items in the collection from which you try to extract the first element. So you might want to add some error checking to ensure the table has rows before trying to extract the first row, if there could be a situation where it doesn't have rows.