SqlDataReader的和并发/释放问题 [英] SqlDataReader and concurrency/deallocation issues

问题描述

运行低于code是给我的错误：

.NET框架的执行被中止升级策略，因为出来的内存。
System.InvalidOperationException：有已与此命令必须先关闭相关联的打开的DataReader

我有以下的code遍布运行我的SQL的地方：

  sql.Append（的String.Format（选择从TABLEID ps_SavedTables其中GUID ='{0}'，GUID））;    使用（IDataReader的读卡器= SqlHelper.GetDataReader（sql.ToString（）））{
        如果（reader.Read（））{
            结果= reader.IsDBNull（0）？的String.Empty：阅读[0]的ToString（）;
        }
        // CDW加入到关闭SqlDataReader的
        reader.Close（）;
    }
 

该GetDataReader由该定义的：

 公共静态SqlDataReader的GetDataReader（SQL字符串，字符串的connectionString）{
    锁（_lock）{
        SqlConnection的连接= NULL;
        尝试{
            连接=的getConnection（的connectionString）;
            //connection.Open（）;
            使用（CMD的SqlCommand =新的SqlCommand（SQL，连接））{
                WriteDebugInfo（GetDataReader，SQL）;
                返回cmd.ExecuteReader（CommandBehavior.CloseConnection）;
            }
        }
        赶上（例外五）{
            如果（连接！= NULL）
                connection.Dispose（）;
            抛出新DataException（SQL，ConnectionString，则E）;
        }    }
}
 

解决方案

锁必须在读者层面......多个线程，读者打开

Running the below code is giving me an error:

.NET Framework execution was aborted by escalation policy because of out of memory. System.InvalidOperationException: There is already an open DataReader associated with this Command which must be closed first.

I have the following code all over the place to run my sql:

sql.Append(string.Format("SELECT TableId FROM ps_SavedTables WHERE guid = '{0}'", guid));

    using (IDataReader reader = SqlHelper.GetDataReader(sql.ToString())) {
        if (reader.Read()) {
            result = reader.IsDBNull(0) ? string.Empty : reader[0].ToString();
        }
        //CDW added to close SqlDataReader
        reader.Close();
    }

The GetDataReader is defined by this:

public static SqlDataReader GetDataReader(string sql, string connectionString) {
    lock (_lock) {
        SqlConnection connection = null;
        try {
            connection = GetConnection(connectionString);
            //connection.Open();
            using (SqlCommand cmd = new SqlCommand(sql, connection)) {
                WriteDebugInfo("GetDataReader", sql);
                return cmd.ExecuteReader(CommandBehavior.CloseConnection);
            }
        }
        catch (Exception e) {
            if (connection != null)
                connection.Dispose();
            throw new DataException(sql, connectionString, e);
        }

    }
}

解决方案

The lock needs to be at the reader level... Multiple threads are opening readers

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