Cannot perform '=' operation on System.Int64 and System.Int64

[Guest]

I'm using a DataView to filter a DataTable based on a long (Int64) value. I
sometimes get an EvaluateException (with the message shown in the subject
line above) on setting the RowFilter property of the DataView. I've tracked
it down to certain "magic" column values for a row already present and the
value I'm filtering for.

Here's a small sample app that demonstrates the problem. I'm using VS.NET
2003 and version 1.1 of the framework.
These are the only two magic values I've been able to isolate so far.

Can anyone shed some light on what causes this and how to avoid it?

Thanks,
Bill

using System;
using System.Data;

namespace DataViewBugDemo
{
/// <summary>
/// Summary description for Class1.
/// </summary>
class BugDemo
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// Create a table with one column
DataTable table = new DataTable("MyTable");
DataColumn column = table.Columns.Add("MyColumn", typeof(System.Int64));

// Add one row with magic value
DataRow row = table.NewRow();
row["MyColumn"] = -7343930372747648618;
table.Rows.Add(row);

// Create a data view
DataView view = new DataView(table);

// Filter for a second magic value
try
{
long filterValue = 6330035203988602880;
view.RowFilter = "MyColumn = " + filterValue.ToString();
Console.WriteLine("Curses, foiled again!");
}
catch (EvaluateException e)
{
Console.WriteLine("Gotcha! ");
Console.WriteLine("Exception: " + e.Message);
}

// Allow time to read the message
Console.ReadLine();
}
}
}

 

[Grzegorz Danowski]

I'm using a DataView to filter a DataTable based on a long (Int64) value.
I
sometimes get an EvaluateException (with the message shown in the subject
line above) on setting the RowFilter property of the DataView. I've
tracked
it down to certain "magic" column values for a row already present and the
value I'm filtering for.
(...)
try
{
long filterValue = 6330035203988602880;
view.RowFilter = "MyColumn = " + filterValue.ToString();
Console.WriteLine("Curses, foiled again!");
}

Yes, I have tried it and had the same result as you - I think that it is a
bug.
I have noticed that conversion to string resolve the problem, for example:

view.RowFilter = "Convert(MyColumn, 'System.String') = '" +
filterValue.ToString() + "'";

Of course, in this case (conversion to string) code is less readable and
probably seeking is less efficient.

Regards,
Grzegorz