我正在尝试在我的代码中进行多个查询,如下所示,但它会在
MySqlDataReader行抛出异常rdr_get_latest_build_notes = get_latest_build_notes_cmd.ExecuteReader();因为我已经开了一个rdr
我用Google搜索并发现@ according to MSDN不受支持,我需要有关如何修复它的指导?
public IEnumerable<BuildNotes_op> RetrieveBuildDetails(string BuildID)
{
....
var conn = new MySql.Data.MySqlClient.MySqlConnection();
conn.ConnectionString = AciDev.aciDevConnectionString;
try
{
Console.WriteLine("Connecting to MySQL...");
conn.Open();
string sql = @"query1";
MySqlCommand cmd = new MySqlCommand(sql, conn);
MySqlDataReader rdr = cmd.ExecuteReader(); --> **rdr open here**
....
while (rdr.Read())
{
.....
if (rdr[4] != DBNull.Value)
....................
else
........
string sql_get_latest_build_notes_cmd = "query2";
MySqlCommand get_latest_build_notes_cmd = new MySqlCommand(sql_get_latest_build_notes_cmd, conn);
MySqlDataReader rdr_get_latest_build_notes = get_latest_build_notes_cmd.ExecuteReader(); --> **throws exception here**
if (rdr_get_latest_build_notes.HasRows)
{
....................
}
rdr_get_latest_build_notes.Close();
if (BuildDetails != null)
{
BuildNotesDetails.Add(BuildDetails);
}
}
rdr.Close();
conn.Close();
return BuildNotesDetails;
}
catch
{
throw;
}
finally
{
conn.Close();
}
例外:
There is already an open DataReader associated with this Connection which must be closed first.
最佳答案 试试这个:
public IEnumerable<BuildNotes_op> RetrieveBuildDetails(string BuildID)
{
var conn = new MySql.Data.MySqlClient.MySqlConnection();
var conn2 = new MySql.Data.MySqlClient.MySqlConnection();
conn.ConnectionString = AciDev.aciDevConnectionString;
try
{
Console.WriteLine("Connecting to MySQL...");
conn.Open();
string sql = @"query1";
MySqlCommand cmd = new MySqlCommand(sql, conn);
MySqlDataReader rdr = cmd.ExecuteReader(); --> **rdr open here**
....
while (rdr.Read())
{
.....
if (rdr[4] != DBNull.Value)
....................
else
........
string sql_get_latest_build_notes_cmd = "query2";
conn2.ConnectionString = AciDev.aciDevConnectionString;
Console.WriteLine("Connecting to MySQL...");
conn2.Open();
MySqlCommand get_latest_build_notes_cmd = new MySqlCommand(sql_get_latest_build_notes_cmd, conn2);
MySqlDataReader rdr_get_latest_build_notes = get_latest_build_notes_cmd.ExecuteReader(); --> **throws exception here**
if (rdr_get_latest_build_notes.HasRows)
{
....................
}
rdr_get_latest_build_notes.Close();
conn2.Close();
if (BuildDetails != null)
{
BuildNotesDetails.Add(BuildDetails);
}
}
rdr_get_latest_build_notes.Close();
rdr.Close();
conn.Close();
conn2.Close();
return BuildNotesDetails;
}
catch
{
throw;
}
finally
{
rdr_get_latest_build_notes.Close();
rdr.Close();
conn.Close();
conn2.Close();
}
创建第二个连接var