How can I tell if my SqlCeDataReader contains any vals after calling SqlCeCommand.ExecuteReader()?

Question

With the code below:

SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow);
itemID = myReader.GetString(0);
packSize = myReader.GetString(1);

...I get an exception, "No data exists for the row/column"

I want it to silently "abort" rather than throwing an exception in this case. Is there a way to test first before the attempted assignment?

I tried this, but it does no good:

SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow);
if (null != myReader.GetString(0))
{
    itemID = myReader.GetString(0);
}
if (null != myReader.GetString(1))
{
    packSize = myReader.GetString(1);
}

Another possibility would be to wrap it in a try..catch and "eat" the exception, but I don't know if that's the best way to go...

Answer 1

This is because you didn't call Read() method after obtaining the DataReader. This does not mean that the result contains no data. It means that the row contains no data.

using (SqlCeDataReader myReader = cmd.ExecuteReader(CommandBehavior.SingleRow))
{
    if (myReader.Read()) // It returns `false` if there is no data
    {
        itemID = myReader.GetString(0);
        packSize = myReader.GetString(1);
    }
}

If the result can contain multiple rows and you want to check to see if the result contains any data, use HasRows:

using (SqlCeDataReader myReader = cmd.ExecuteReader())
{
    if (myReader.HasRows)
    {
        while (myReader.Read())
        {
            // read values from `myReader`
        }
    }
}