Question

此代码以前一直运行良好。但是，我需要对我的读写进行事务处理，当尝试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;
}

我之前已将查询打印到控制台，以确保它不是空白。

参考方法。

    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();
    }

Answer 1

问题/解决方案是删除此行

public void BeginTransaction()
{
   // SelectCmd = Conn.CreateCommand();  //Problem Line
    MySqlTransaction NewTransaction = Conn.BeginTransaction();
    SelectCmd.Connection = Conn;
    SelectCmd.Transaction = NewTransaction;
}

在Transactionalized时，CommandText属性未正确初始化错误

1 个答案: