Get array length dynamically

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Hi all,

I have a datareader and put that value in an array like below

C#

Task[] objOfTask;
             myReader = cmd.ExecuteReader();
             int counter=0;
             int index = 0;

            while (myReader.Read())
            {
                counter++;
            }
            objOfTask = new Task[counter];
            while (index < counter)
            {
                    objOfTask[index] = new Task();

                    objOfTask[index].Goal = myReader["goals"].ToString();
                    objOfTask[index].Note = myReader["notes"].ToString();
                    objOfTask[index].Status = Convert.ToBoolean(myReader["status"]);

                    index++;
            }

            return objOfTask;

But after Read(), its repeating the last result. So is there any way to get no of rows before Read() ?

Posted 18-Oct-12 23:48pm

akee seth

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Comments

I.explore.code 19-Oct-12 5:57am

Can you not use List<Task> rather than an Task[]? That way you can populate the List with just one loop.

2 solutions

Solution 3

I would be tempted to rewrite the code like so, since it reduces two loops to just one and would still work:

C#

List<task>tasks = new List<task>();
            myReader = cmd.ExecuteReader();
            while (myReader.Read())
            {
                Task t = new Task();
                t.Goal = myReader["goals"].ToString();
                t.Note = myReader["notes"].ToString();
                t.Status = Convert.ToBoolean(myReader["status"]);
                tasks.Add(t);
            }

            return tasks;

Because a DataReader is a forward only cursor that can only move one record at a time which is what happens when you call Read() and which is why you need to call it in the first place to see if there is data available. HasRows is another property of DataReader that can only tell whether or not there are rows available not how many of them.

Posted 19-Oct-12 0:23am

I.explore.code

Updated 19-Oct-12 0:25am

v2

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Accepted Answer · 2012-10-19T00:01:00

Solution 1

Each time you call Read, it fetches a new row, or if there are no more rows returns false.
So your while loop:

C#

while (myReader.Read())
{
    counter++;
}

Has successfully fetched and discarded each and every row.
Instead, use a List, and only loop the once:

C#

List<Task> list = new List<Task>();
while (myReader.Read())
{
    Task t = new Task();

    t.Goal = myReader["goals"].ToString();
    t.Note = myReader["notes"].ToString();
    t.Status = Convert.ToBoolean(myReader["status"]);
    list.Add(t);
}
return list.ToArray();

Posted 19-Oct-12 0:01am

OriginalGriff

Comments

I.explore.code 19-Oct-12 6:07am

Looks like I can't type fast enough ;) I will remove my solution then. my 5! I would use this.

OriginalGriff 19-Oct-12 6:20am

No need to delete solutions if they are posted at the same time - it happens all the time. Your solution may have a subtle difference or improvement over mine which could help the OP.

I.explore.code 19-Oct-12 6:24am

fair enough then, I have put it back! although there is not a drastic difference from yours.

Get array length dynamically

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Get array length dynamically

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