Dapper GridReader already Disposed Error

.net, dapper, sql, sql-server

Solution

The reader will dispose itself when it fails to find any more results grids; basically, your C# code looks fine, but the suggestion is that your proc is only returning 1 grid. The following works fine, for example:

using (var reader = connection.QueryMultiple(
    "select 1; select 2 where 1 = 0; select 3 where 1 = 0; select 4;"))
{
    var one = reader.Read<int>().ToArray();
    var two = reader.Read<int>().ToArray();
    var three = reader.Read<int>().ToArray();
    var four = reader.Read<int>().ToArray();
    try { // only returned four grids; expect a fifth read to fail
        reader.Read<int>();
        throw new InvalidOperationException("this should not have worked!");
    }
    catch (ObjectDisposedException) {/* expected; success */}

    one.Length.IsEqualTo(1);
    one[0].IsEqualTo(1);
    two.Length.IsEqualTo(0);
    three.Length.IsEqualTo(0);
    four.Length.IsEqualTo(1);
    four[0].IsEqualTo(4);
}

I might try to improve the error message, but I suspect the error is in your SP.

Problem

I'm using Dapper dot net to execute a stored procedure that returns 4 result sets. Here's how I'm doing it: ``` public Results Search(Query query) { if (query == null) throw new ArgumentNullException("query"); Results results; var q = _sqlConnection.QueryMultiple("MySchema.MySproc", query, commandType: CommandType.StoredProcedure); { results = q.Read<Results>().First(); results.CheckAlertResults = q.Read<Results.CheckAlertResult>().ToArray(); // Cannot access a disposed object.Object name: 'GridReader'. results.PersonAlertResultRows = q.Read<Results.PersonAlertResultRow>().ToArray(); results.RoutingAlertResults = q.Read<Results.RoutingAlertResult>().ToArray(); } return results; } ``` The first result set will only contain 1 row. It corresponds to a couple of primitive properties on my `Results` class. The other 3 result sets will have many rows and will populate 3 complex array properties on the `Results` class. For some reason, I'm getting Cannot access a disposed object.Object name: 'GridReader'. Check my code to see where. I have verified that the procedure is working correctly when called from LinqPad, which uses Linq2Sql. What am I doing wrong?

Original source