How to solve error - unable to evaluate the expression. Operation not supported. Unknown error: 0x80070057

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DataTable dttable = new DataTable();
dttable.Columns.Add("billno", typeof(String));
dttable.Columns.Add("date", typeof(DateTime));
dttable.Columns.Add("time", typeof(String));
dttable.Columns.Add("covers", typeof(Decimal));
dttable.Columns.Add("trcode", typeof(String));
dttable.Columns.Add("scode", typeof(String));
dttable.Columns.Add("gname", typeof(String));
dttable.Columns.Add("total", typeof(Decimal));
dttable.Columns.Add("login", typeof(String));
dttable.Columns.Add("resno", typeof(String));
dttable.Columns.Add("custcode", typeof(String));
dttable.Columns.Add("resnum", typeof(Int32));
dttable.Columns.Add("sname", typeof(String));
dttable.Columns.Add("name", typeof(String));
dttable.Columns.Add("qty", typeof(Decimal));
dttable.Columns.Add("rate", typeof(Decimal));

var rows = from mobjbmast in Context.bmasts.AsEnumerable()
           join mobjbtran in Context.btrans
           on mobjbmast.billno equals mobjbtran.billno
           join mobjwaiter in Context.waiters
           on mobjbmast.scode equals mobjwaiter.code
           where mobjbmast.billno == mbillno
           select dttable.LoadDataRow(new object[]
           {
                 mobjbmast.billno,
                 mobjbmast.date,
                 mobjbmast.time,
                 mobjbmast.covers,
                 mobjbmast.trcode,
                 mobjbmast.scode,
                 mobjbmast.gname,
                 mobjbmast.total,
                 mobjbmast.login,
                 mobjbmast.resno,
                 mobjbmast.custcode,
                 mobjbmast.resnum,
                 mobjwaiter.name,
                 mobjbtran.name,
                 mobjbtran.qty,
                 mobjbtran.rate
           }, false);

The above code returns no rows in the datatable and on debugging the 'rows' variable show the error :

Unable to evaluate the expression. Operation not supported. Unknown error: 0x80070057

Please suggest. Thanks in advance.

What I have tried:

var rows = from mobjbmast in Context.bmasts.AsEnumerable()
           join mobjbtran in Context.btrans.AsEnumerable()
           on mobjbmast.billno equals mobjbtran.billno
           join mobjwaiter in Context.waiters.AsEnumerable()
           on mobjbmast.scode equals mobjwaiter.code
           where mobjbmast.billno == mbillno
           select new { billno = mobjbmast.billno, date = mobjbmast.date, time = mobjbmast.time, trcode = mobjbmast.trcode };

Even this gives the same error. If I change the AsEnumerable() to ToList() then I get Enumeration yielded no results.

Posted 9-Apr-19 2:45am

Priya-Kiko

Updated 13-Apr-19 0:22am

v2

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Comments

Maciej Los 9-Apr-19 12:13pm

Have you tried to use AsEnumerable() method with other data sources: Context.btrans, Context.waiters?

Priya-Kiko 10-Apr-19 1:55am

Thank you for the response. Yes I did try with other data sources too adding AsEnumerable(). Yet the issue persisted.

2 solutions

Solution 1

You may try

C#

IEnumerable<DataRow> _query = ...... Your expression

DataTable boundTable = _query.CopyToDataTable<DataRow>();

Posted 9-Apr-19 2:50am

Nirav Prabtani

v2

Comments

Priya-Kiko 11-Apr-19 3:47am

Thanks for the response. I tried doing this as you suggested :

IEnumerable<datarow> _query = from mobjbmast in Context.bmasts.AsEnumerable()
join mobjbtran in Context.btrans.AsEnumerable()
on mobjbmast.billno equals mobjbtran.billno
join mobjwaiter in Context.waiters.AsEnumerable()
on mobjbmast.scode equals mobjwaiter.code
where mobjbmast.billno == mbillno
select mobjbmast;
But it doesn't compile. How to construct the query please help.

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Priya-Kiko · Accepted Answer · 2019-04-13T00:23:00

This code works for me. Got this solution from one of the websites. Posting this as answer so it can help some body else. The below code is for querying data from joined tables on some condition and loading a Datatable (with known columns) from the resultant object array.

DataTable dttable = new DataTable();

dttable.Columns.Add("billno", typeof(String));
dttable.Columns.Add("date", typeof(DateTime));
dttable.Columns.Add("time", typeof(String));
dttable.Columns.Add("covers", typeof(Decimal));
dttable.Columns.Add("trcode", typeof(String));
dttable.Columns.Add("scode", typeof(String));
dttable.Columns.Add("gname", typeof(String));
dttable.Columns.Add("total", typeof(Decimal));
dttable.Columns.Add("login", typeof(String));
dttable.Columns.Add("resno", typeof(String));
dttable.Columns.Add("custcode", typeof(String));
dttable.Columns.Add("resnum", typeof(Int32));
dttable.Columns.Add("sname", typeof(String));
dttable.Columns.Add("name", typeof(String));
dttable.Columns.Add("qty", typeof(Decimal));
dttable.Columns.Add("rate", typeof(Decimal));

var rows = from mobjbmast in Context.bmasts.AsEnumerable()
           join mobjbtran in Context.btrans
           on mobjbmast.billno equals mobjbtran.billno
           join mobjwaiter in Context.waiters
           on mobjbmast.scode equals mobjwaiter.code
           where mobjbmast.billno == mbillno
           let billarray = new object[]
           {
                mobjbmast.billno,
                mobjbmast.date,
                mobjbmast.time,
                mobjbmast.covers,
                mobjbmast.trcode,
                mobjbmast.scode,
                mobjbmast.gname,
                mobjbmast.total,
                mobjbmast.login,
                mobjbmast.resno,
                mobjbmast.custcode,
                mobjbmast.resnum,
                mobjwaiter.name,
                mobjbtran.name,
                mobjbtran.qty,
                mobjbtran.rate
            }
            select billarray;
            foreach (var array in rows)
            {
                dttable.Rows.Add(array);
            }