结合使用BeginExecuteNonQuery和异步任务

Question

我正在为基础存储库添加一些方法，以处理将处理使用异步任务的查询的其他代码。 我基本上只是在现有的BeginExecuteNonQuery和EndExecuteNonQuery方法周围包装一个Task 。

使用这样的方法有什么陷阱吗？ 在AsyncCallback中执行SQL语句期间捕获发生的异常是否正确？

public class Repo
{
    public class SqlCommandAsyncState<T>
    {
        public SqlCommand SqlCommand { get; set; }
        public TaskCompletionSource<T> TaskCompletionSource { get; set; }

        public SqlCommandAsyncState()
        {
            TaskCompletionSource = new TaskCompletionSource<T>();
        }
    }

    private int? sqlCommand_EndExecuteNonQuery(SqlCommand sqlCommand, IAsyncResult result)
    {

        try
        {

            return sqlCommand.EndExecuteNonQuery(result);
        }
        catch (Exception ex)
        {

            // LogError(LogImportance.Fatal, ex);
        }
        finally
        {
            sqlCommand.Connection.Dispose();
        }

        return null;
    }

    private void sqlCommand_ExecuteNonQueryForIntCompleted(IAsyncResult result)
    {
        SqlCommandAsyncState<int?> state = result.AsyncState as SqlCommandAsyncState<int?>;
        state.TaskCompletionSource.SetResult(sqlCommand_EndExecuteNonQuery(state.SqlCommand, result));
    }

    private void sqlCommand_ExecuteNonQueryForBoolCompleted(IAsyncResult result)
    {
        SqlCommandAsyncState<bool?> state = result.AsyncState as SqlCommandAsyncState<bool?>;
        int? rowsAffected = sqlCommand_EndExecuteNonQuery(state.SqlCommand, result);
        state.TaskCompletionSource.SetResult(rowsAffected.HasValue ? (bool?)(rowsAffected.Value > 0) : null);
    }

    public async Task<bool?> UpdateAsync(string commandText, SqlParameter[] parameters)
    {
        SqlCommandAsyncState<bool?> state = new SqlCommandAsyncState<bool?>();

        SqlConnection sql_Connection = new SqlConnection(ConnectionString);

        try
        {
            sql_Connection.Open();
            state.SqlCommand = new SqlCommand(commandText, sql_Connection);
            state.SqlCommand.CommandType = CommandType.StoredProcedure;
            state.SqlCommand.Parameters.AddRange(parameters);
            state.SqlCommand.BeginExecuteNonQuery(new AsyncCallback(sqlCommand_ExecuteNonQueryForBoolCompleted), state);
        }
        catch (Exception ex)
        {
            // LogError(LogImportance.Fatal, ex);
            state.TaskCompletionSource.SetResult(null);
        }

        return await state.TaskCompletionSource.Task;
    }

    public async Task<int?> UpdateWithCountAsync(string commandText, SqlParameter[] parameters)
    {
        SqlCommandAsyncState<int?> state = new SqlCommandAsyncState<int?>();

        SqlConnection sql_Connection = new SqlConnection(ConnectionString);

        try
        {
            sql_Connection.Open();
            state.SqlCommand = new SqlCommand(commandText, sql_Connection);
            state.SqlCommand.CommandType = CommandType.StoredProcedure;
            state.SqlCommand.Parameters.AddRange(parameters);
            state.SqlCommand.BeginExecuteNonQuery(new AsyncCallback(sqlCommand_ExecuteNonQueryForIntCompleted), state);
        }
        catch (Exception ex)
        {
            // LogError(LogImportance.Fatal, ex);
            state.TaskCompletionSource.SetResult(null);
        }

        return await state.TaskCompletionSource.Task;
    }
}

Answer 1

Task.Factory.FromAsync旨在做到这一点。