OrderBy with Dynamic Linq

Question

I am trying to sort some data from entity before passing them to another function. Both tableName and columnName are selected dynamically. This is what I'm doing:

string tableName = cboSelectTable.Text.ToString();
var comboBoxColumn = from a in Context.RULES where 
                     a.ISCOMBOBOXCOLUMN == "Y" select a.COLUMN;

foreach (var colName in comboBoxColumn)
  {
    var getTableName = entityModel.GetType()
                                  .GetProperty(tableName)
                                  .GetValue(entityModel, null);
    var getData = ((IQueryable<object>)getTableName)
                                      .Where(colName + "!=null")
                                      .Select(colName)
                                      .Distinct()
                                      .OrderBy('"'+ colName +'"');
    dgvCboColumn(getData, colName);
  }

But this is not sorting the data. I also tried some other methods too, but couldn't figure it out. How can I resolve this?

yes, it throws exception that the column name does not exist in String[at index 0]. — Paradox, Feb 04 '15 at 10:51

score 1 · Answer 1 · edited May 23 '17 at 12:12

1

I do not think that is the way, .OrderBy(...) works. Try ordering by an attribute:

SomeList.OrderBy(l => l.SomeAttribute);

I suspect ordering by a string results in each element being ordered by the same attribute, thus not ordering at all. In addition, I am not sure, if your where-clause works like that.

There is another relevant SO question already answered. You might want to have a look at it: click me!

edited May 23 '17 at 12:12

Community

1
1

answered Feb 04 '15 at 10:54

Nephtyz

103
1
9

This is using `System.Linq.Dynamic`, a small library on top of LINQ. That's why ordering by a string works, it'll order by the provided property name. – Lucas Trzesniewski Feb 04 '15 at 10:55
Thanks. I was not aware of the difference. – Nephtyz Feb 04 '15 at 10:58
It doesn't allow me to use ( l => l.someCol) in this case. – Paradox Feb 04 '15 at 11:04

Lucas Trzesniewski · Accepted Answer · 2015-02-04T11:50:58.633

0

~~You can simply place the Select after the OrderBy:~~

var getData = ((IQueryable<object>)getTableName)
                  .Where(colName + "!=null")
                  .OrderBy(colName)
                  .Select(colName)
                  .Distinct();

This will allow you to reference the column name. (doesn't seem to work for some reason).

Alternatively, you can reference the current instance:

var getData = ((IQueryable<object>)getTableName)
                  .Where(colName + "!=null")
                  .Select(colName)
                  .Distinct()
                  .OrderBy("it");

edited Feb 04 '15 at 11:50

answered Feb 04 '15 at 10:54

Lucas Trzesniewski

50,214
11
107
158

Its not sorting the data, giving a list of unsorted data. Same as before. – Paradox Feb 04 '15 at 11:03
Weird. Did you try both approaches? – Lucas Trzesniewski Feb 04 '15 at 11:04
sorry, I didn't notice your update. The second approach works, thanks. – Paradox Feb 04 '15 at 11:07

OrderBy with Dynamic Linq

2 Answers2