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Issue with Where Clause for a DataTable - String Works - Integer does not... ? #959
Description
Hello,
I have a bunch of DataTables I need to query dynamically.
I have a GenerateClause function that generates a simple where clause based on the type of column being queried...
For example, a String column might look like (City = "Seattle")
and an Int32 field might look like (Size = 3)
However, the string field where clause works fine - but the Int32 field does not work - and generates an error "Specified Cast is not Valid"
Any thoughts as to what might be causing this error message? I will need to put DataTime, Doubles, DateOnly, etc. where clauses as well as the String and Int32.
Here is the code I am using - where the GenateWhereClause is used to gen the string containing the actual clause...
DataTable ColumnSelTable = dataSet_DataCleaning.Tables["RemoveByCol"];
CurrWhereClause = GenerateWhereClause(ColumnSelTable);
var dynamicQuery = CurrTable.AsEnumerable().AsQueryable();
var dynamicQuery2 = dynamicQuery.Where(DynLinqConfig, CurrWhereClause).ToList();
ResultingDataTable = dynamicQuery2.CopyToDataTable();
Activity
CDNConsultant commentedon Nov 21, 2025
It appears that using DynamicLINQ with Int64, Double, and some other field types all hinges on how you have the Where clause formatted
I was using a where clause that was generated and it looked like Int64Col == 11 for example - and it failed when I then ran the following command
dynamicQuery.Where(DynLinqConfig, CurrWhereClause).ToList();HOWEVER, if you use parameters such as ...
It all works fine. It is functionally the same - but DynamicLINQ seems to have an issue telling how to map the datatype if you don't use parameters.
This will make it a little difficult to use my current GenerateWhereClause code - but I can figure a way around that.
Thought I would post this here to help anyone else that runs into this issue.