Question

Scenario:

 const string srchFormatter = "{0} {1} {2}";

 var result = from c in db.ContactsDumps1s
                     where string.Format(srchFormatter, c.FirstName, c.MiddleName, c.LastName).Contains(txtSearch.Text.Trim())
                     select new { c.FirstName, c.MiddleName, c.LastName };

Error:

Method ‘System.String Format(System.String, System.Object, System.Object, System.Object)’ has no supported translation to SQL.

Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.

Exception Details: System.NotSupportedException: Method ‘System.String
Format(System.String, System.Object, System.Object, System.Object)’
has no supported translation to SQL.

Can anybody please let me know why am I not able to search in this manner & any alternatives for this search?

This is what I plan to achieve :

select FirstName, MiddleName, LastName 
from ContactsDumps1 
where FirstName+MiddleName+LastName like '%Search_String%'

by using LINQ.

Answer 1

Seems like you’re doing a LINQ-to-SQL query, since your DB context is tied to a database connection. In doing this, you’re issuing a query to your database. Think about the query that you’re constructing:

from c in db.ContactsDumps1s
                     where string.Format(srchFormatter, c.FirstName, c.MiddleName, c.LastName).Contains(txtSearch.Text.Trim())
                     select new { c.FirstName, c.MiddleName, c.LastName };

Which probably translates to something like:

SELECT FN, MN, LN
FROM ContactsDumps1s
WHERE 'FN FN FN' Contains SomeTextValue

That doesn’t really translate well. I think what you’re trying to do is a LIKE – where FirstName Starts With SomeTextValue.

So you may want to try:

    from c in db.ContactsDumps1s
    where c.FirstName.StartsWith(txtSearch.Text.Trim()) ||
          c.MiddleName.StartsWith(txtSearch.Text.Trim()) ||
          c.LastName.StartsWith(txtSearch.Text.Trim())
    select new { c.FirstName, c.MiddleName, c.LastName };

I may not understand what you’re exactly trying to do, but hopefully this helps. Let me know if I’m missing something and I’ll clarify my answer.

UPDATE: I updated my suggested LINQ statement to search FirstName, MiddleName or LastName for the text in txtSearch.

UPDATE #2: I noticed your updated question and what you’re looking to do. Here’s an approach that may work for you:

from c in db.ContactsDumps1s
where (c.FirstName + " " + c.MiddleName + " " + c.LastName).StartsWith(txtSearch.Text.Trim())
select new { c.FirstName, c.MiddleName, c.LastName };

Using LINQPad, I did something similar and the generated SQL from it is:

SELECT [t0].[FirstName], [t0].[MiddleName], [t0].[LastName]
FROM [SalesLT].[Customer] AS [t0]
WHERE (([t0].[FirstName] + @p0) + ([t0].[MiddleName] + @p0) + [t0].[LastName]) LIKE @p1

That roughly translates to what you want to do.

Hope this helps.