FilterExpression Linq

[David Rhodes]

I'm trying to get the filterExpressions working on my Linq query using the Dynamic Linq Library but am getting this error

LINQ to Entities does not recognize the method 'System.String ToString()' method, and this method cannot be translated into a store expression.

It looks like the filterExpression uses ToString() which is causing the error

(iif(LogType.Name == null, "", LogType.Name).ToString().Contains("Error"))

My code is

string filterExpression = (sender as RadGrid).MasterTableView.FilterExpression;

logs = db.Logs
        .Where(x => x.SystemId.Equals(this.SystemId.Value))
        .Where(filterExpression)
        .OrderByDescending(x => x.OccurredOn)
        .Skip(skip)
        .Take(pageSize)
        .ToList();

[David Rhodes]

This seems to do the trick

string filterExpression = (sender as RadGrid).MasterTableView.FilterExpression.Replace(".ToString()", "");

[David Rhodes]

It also errors with Date filters

LINQ to Entities does not recognize the method 'System.DateTime Parse(System.String)' method, and this method cannot be translated into a store expression.

Any idea how this can be fixed?

[Antonio Stoilkov]

Hi David,

The experienced behavior is expected. Microsoft LINQ to Entities does not implement the DateTime.Parse method and this is a know issue. There are multiple topics on the Internet which state the same problem. You could take a look at discussion below which explains the problem:

• http://stackoverflow.com/questions/10384862/linq-to-entities-does-not-recognize-the-method-system-datetime-parsesystem-str

Regards,
Antonio Stoilkov
Telerik

[kuntal]

01.string FinalQuery = "";
02.            if (filter.Contains("DateTime.Parse("))
03.            {
04.                var filters = filter.Split(new string[] { "DateTime.Parse(" }, StringSplitOptions.RemoveEmptyEntries);
05.                for (int i = 0; i < filters.Count(); i++)
06.                {
07.                    if (i != 0)
08.                    {
09.                        var oldDate = filters[i].Substring(1, 22);
10.                        var newDate = DateTime.Parse(oldDate);
11.                        filters[i] = filters[i].Replace('\"' + oldDate + "\")", "DateTime(" + newDate.Year + ',' + newDate.Month + ',' + newDate.Day + ',' + newDate.Hour + ',' + newDate.Minute + ',' + newDate.Second + ")");
12.                    }
13.                    FinalQuery = FinalQuery + filters[i];
14.                }
15.            }
16.            else
17.                FinalQuery = filter;

I know this is quite an old question but this is how to get rid of that part of issue.
At least this is how I fixed it.