Invalid attempt to call Read when reader is closed while using dapper

Question

Invalid attempt to call Read when reader is closed while using dapper

asp.net-mvc c# dapper sqldatareader

Question

While retrieving the records from table using dapper framework I am getting the below error

Invalid attempt to call Read when reader is closed

and below is my code

var sql = "SELECT * FROM LMS_QuestionCategory";
                var rows = new List<Dictionary<string, int>>();

                using (IDbConnection dbConnection = Connection)
                {
                    var reader = dbConnection.ExecuteReader(sql);

                    while (reader.Read())
                    {
                        var dict = new Dictionary<string, int>();

                        for (var i = 0; i < reader.FieldCount; i++)
                        {
                            dict[reader.GetName(i)] = reader.GetInt32(i);
                        }

                        rows.Add(dict);
                    }
                }

Why I am getting this error ?

XamDev

Popular Answer

In my very specific case, I was using a CommandDefinition for the select and it was throwing the referenced error:

CommandDefinition queryDefinition = _queryBuilder.UpdateQuery(_dbConn, _transaction, collectionName, item);

await QueryAsync<T>(CommandDefinition);

I changed it as follows and it worked:

await QueryAsync<T>("SELECT * FROM table_name",param,null,null, commandType : CommandType.Text);

Hope it helps to somebody

Henry Rodriguez

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apomene · Accepted Answer · 3/27/2017 12:11:00 PM

Accepted Answer

You must open the connection:

using (IDbConnection dbConnection = Connection)
{
   dbConnection.Open() //<--open the connection
   var reader = dbConnection.ExecuteReader(sql);
    ...

apomene

Invalid attempt to call Read when reader is closed while using dapper

Question

Fastest Dapper Plus Extensions

Accepted Answer

Popular Answer

Performance

Expression Evaluator