此代码之前运行良好。然而,我需要事务化我的读写,当我试图通过事务化我的读取来开始该过程时,我遇到了这个 commandText 未初始化的错误。
确切错误,第 156 行是 DA.Fill(tbl);
Error: System.InvalidOperationException: The CommandText property has not been properly initialized.
at MySql.Data.MySqlClient.ExceptionInterceptor.Throw(Exception exception)
at MySql.Data.MySqlClient.MySqlConnection.Throw(Exception ex)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteReader(CommandBehavior behavior)
at MySql.Data.MySqlClient.MySqlCommand.ExecuteDbDataReader(CommandBehavior behavior)
at System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.Fill(DataTable[] dataTables, Int32 startRecord, Int32 maxRecords, IDbCommand command, CommandBehavior behavior)
at System.Data.Common.DbDataAdapter.Fill(DataTable dataTable)
at MDB_N2000.DatabaseManager.GetTable(TableQuery query) in C:\Users\Tcordeau.pub\DocumentsException thrown: 'System.InvalidOperationException' in MySql.Data.dll
\MDB-N2000\MDB-N2000\Model\DatabaseManager.cs:line 156 The CommandText property has not been properly initialized.
调用 LoadTable。
public void LoadTable() { if (Db.IsConnOpen) { Db.BeginTransaction(); // Persist the selected row across table reload by keeping track of the row's first value. // For this to work, tables need to always have an autonumbered integer index in the first column. // Store the row index. if (Vals.Any()) if (Vals[0].Val != null) if (Vals[0].Val.GetType() == typeof(int)) RowID = Vals[0].Val; // For tables in the sub-tables viewer, get the key value of the main table of the module // to use as a parameter in the SQL select query. if (!IsMainTable) { LoadTableQuery.Prms[0].Val = MainVM.Modules.SelectedModule.Vwr.Table.Vals[0].Val; } // Get the table from the database Tbl = Db.GetTable(LoadTableQuery); DataTable MainTable = Db.GetTable(LoadTableQuery); MainTable.TableName = "MainTable"; dv.Table = MainTable; // Retrieve the row index and set the selected row. if (Vals.Any()) if (Vals[0].Val != null) if (Vals[0].Val.GetType() == typeof(int)) Tbl.DefaultView.Sort = Tbl.Columns[0].ColumnName.ToString(); //SelectedRowIndex = Tbl.DefaultView.Find(RowID); Db.CommitTransaction(); } }
转到 GetTable。
public DataTable GetTable(TableQuery query) { DataTable tbl = new DataTable(); if (IsConnOpen) { try { SelectCmd.Parameters.Clear(); SelectCmd.CommandText = query.Qry; for (int i = 0; i < query.Prms.Count; i++) { SelectCmd.Parameters.AddWithValue(query.Prms[i].Col, query.Prms[i].Val); } // DA = MySQLDataAdapter DA.Fill(tbl); tbl.DefaultView.Sort = tbl.Columns[0].ColumnName.ToString() + " ASC"; } catch (MySqlException ex) { Msg = "Error: " + ex.Number + " " + ex.Message + " from Qry = " + query.Qry; } catch (Exception ex) { Msg = "Error: " + ex + " " + ex.Message; } } else { Msg = "Not Connected"; } return tbl; }
我之前已经将查询打印到控制台以确保它不是空白的。
引用方法。
private DatabaseManager()
{
Acct = new Account();
SelectCmd = new MySqlCommand() { Connection = Conn };
UpdateCmd = new MySqlCommand() { Connection = Conn };
Cmd = new MySqlCommand() { Connection = Conn };
DA = new MySqlDataAdapter(SelectCmd)
{
UpdateCommand = UpdateCmd
};
Msg = "Ready to Connect";
}
// Creates a new transaction and returns the command it's attached to.
public void BeginTransaction()
{
SelectCmd = Conn.CreateCommand();
MySqlTransaction NewTransaction = Conn.BeginTransaction();
SelectCmd.Connection = Conn;
SelectCmd.Transaction = NewTransaction;
}
//rollsback transaction
public void RevertTransaction()
{
Cmd.Transaction.Rollback();
}
//adds a query to the transaction
public void TransactionQuery(TableQuery NewQuery)
{
Cmd.CommandText = NewQuery.Qry;
Cmd.ExecuteNonQuery();
}
//commits transaction
public void CommitTransaction()
{
SelectCmd.Transaction.Commit();
}
最佳答案
问题/解决方案是删除这一行
public void BeginTransaction()
{
// SelectCmd = Conn.CreateCommand(); //Problem Line
MySqlTransaction NewTransaction = Conn.BeginTransaction();
SelectCmd.Connection = Conn;
SelectCmd.Transaction = NewTransaction;
}
关于c# - 事务化时 CommandText 属性未正确初始化错误,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/49516353/