How Can I Convert an Integer to a String in LINQ to Entities without Errors?

LINQ to Entities: Converting Integers to Strings

This article addresses the challenge of converting integer (int) values to strings within LINQ to Entities queries, specifically highlighting the differences between C# and VB.NET and providing a solution compatible with Entity Framework v4. Directly using ToString() on an integer field within a LINQ to Entities query often results in a compilation error or runtime exception because ToString() isn't directly translatable into SQL.

C# Strictness vs. VB.NET Flexibility

While VB.NET might offer more implicit type conversion flexibility, C#'s stricter type system requires a more explicit approach. This difference leads to the need for a workaround within the LINQ to Entities context.

Solution using SqlFunctions.StringConvert

The most effective solution for Entity Framework v4 involves leveraging the SqlFunctions.StringConvert method. Since this method doesn't directly support int as input, a cast to double or decimal is necessary before conversion:

var items = from c in contacts
            select new ListItem
            {
                Value = SqlFunctions.StringConvert((double)c.ContactId).Trim(),
                Text = c.Name
            };

This code snippet provides a clean and efficient way to perform the necessary type conversion within the constraints of LINQ to Entities, ensuring compatibility and avoiding errors. The .Trim() method is included to handle any potential leading or trailing whitespace that might be introduced by the conversion.

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