LinqPad 动态 sql 并显示结果

Question

我正在使用 LinqPad 执行一些动态 sql，当我调用 .Dump() 时它返回 IEnumerable。我希望它显示其返回的匿名类型的结果。在 LinqPad 中执行动态 sql 语句并显示结果的任何帮助将不胜感激。

这是我正在尝试做的代码片段：

// Any sql string for example.
var query = "SELECT DISTINCT [CustomerId] FROM Customers Where CustomerId = 2";

var dyn = this.ExecuteQuery<dynamic>(query);

LINQPad.Extensions.Dump(dyn);

Answer 1

您使用 IDataRecord 走在正确的轨道上。要使输出动态化，请使用 DynamicObject：

static class Extensions
{
    public static IEnumerable<dynamic> ExecuteSQL (this DataContext dc, string sql)
    {
        var cx = new SqlConnection (dc.Connection.ConnectionString);
        cx.Open();
        return new SqlCommand (sql, cx).ExecuteReader (CommandBehavior.CloseConnection).Cast<IDataRecord>().Select (r => new DynamicDataRecord (r));
    }
}

class DynamicDataRecord : System.Dynamic.DynamicObject
{
    readonly IDataRecord _row;
    public DynamicDataRecord (IDataRecord row) { _row = row; }

    public override bool TryConvert (System.Dynamic.ConvertBinder binder, out object result)
    {
        if (binder.Type == typeof (IDataRecord))
        {
            result = _row;
            return true;
        }
        return base.TryConvert (binder, out result);
    }

    public override bool TryInvokeMember (System.Dynamic.InvokeMemberBinder binder, object [] args, out object result)
    {
        if (binder.Name == "Dump")
        {
            if (args.Length == 0)
                _row.Dump ();
            else if (args.Length == 1 && args [0] is int)
                _row.Dump ((int)args [0]);
            else if (args.Length == 1 && args [0] is string)
                _row.Dump ((string)args [0]);
            else if (args.Length == 2)
                _row.Dump (args [0] as string, args [1] as int?);
            else
                _row.Dump ();
            result = _row;
            return true;
        }
        return base.TryInvokeMember (binder, args, out result);
    }

    public override bool TryGetMember (System.Dynamic.GetMemberBinder binder, out object result)
    {
        result = _row [binder.Name];
        if (result is DBNull) result = null;
        return true;
    }

    public override bool TryGetIndex (System.Dynamic.GetIndexBinder binder, object [] indexes, out object result)
    {
        if (indexes.Length == 1)
        {
            result = _row [int.Parse (indexes [0].ToString ())];
            return true;
        }
        return base.TryGetIndex (binder, indexes, out result);
    }

    public override IEnumerable<string> GetDynamicMemberNames ()
    {
        return Enumerable.Range (0, _row.FieldCount).Select (i => _row.GetName (i));
    }
}

这将允许以下内容：

this.ExecuteSQL ("select * from customer").GroupBy (c => c.Name).Dump();

编辑：从 v4.53.02 开始，此功能现在在 LINQPad中可用。你现在可以去：

ExecuteQueryDynamic ("SELECT DISTINCT * FROM Customer WHERE ID = {0}", 2)

Answer 2

所以我所做的就是这样得到结果，但我认为一定有更好的方法。

using (SqlConnection connection = new SqlConnection(this.Connection.ConnectionString))
{
  connection.Open();

  SqlCommand command = new SqlCommand(query, connection);
  SqlDataReader reader = command.ExecuteReader();

  reader.Cast<IDataRecord>().AsQueryable().Dump();      
}