Non-Stored Procedure Query (CommandType=Text) with Dapper and parameters

Question

I am trying to call a piece of SQL with parameters in Dapper. It is NOT a stored procedure (I have that working fine with parameters)

inputCustomerName = "Our Customer";
inputStationName  = Null;

    var parameters = new
    {
        customerName = inputCustomerName ,
        stationName = inputStationName    
    };     

    ...

    using (var dbConn = dataProvider.CreateConnection)
    {
        dbConn.ConnectionString = connectionString;
        dbConn.Open();
        returnValue = dbConn.Query<T>(sql: sql, commandType: commandType, param: parameters);
        dbConn.Close();
    }

The relevant part of the SQL is

"    ...

     WHERE 
        Customer = ISNULL(@customerName,Customer)
        AND Station = ISNULL(@stationName,Station)
";

I keep getting "Invalid type owner for DynamicMethod". (I got this also when using DynamicParameters instead of the anomymous object).

The SQL runs fine on the database itself (given I declare and @populate @customerName and stationName).

I suspect I have done something quite simple wrong - can anyone enlighten me?

Read it before I posted, Not my situaition, I don't think - I am passing in an object with properties as params, not an array. — kpollock
– kpollock, Commented May 4, 2017 at 12:37
Can you try to set the value of inputStationName to DBNull.Value instead of null? — Lenny32
– Lenny32, Commented May 4, 2017 at 12:43
I have previously tried populating both parameters with a value, it makes no difference. — kpollock
– kpollock, Commented May 4, 2017 at 12:48

kpollock · Accepted Answer · 2017-05-04 13:49:15Z

0

The answer was, in the end, an issue in code not included in the question - for which I thoroughly apologise.

The issue was that T was an Interface, and that was what was causing Dapper to blow up. There's probably something under the hood that means you can only use classes, not interfaces as the type param to Query. Though I have never seen that restriction explicitly stated.

Shame, (but I can imagine a few reasons why)

edited May 4, 2017 at 13:49

answered May 4, 2017 at 13:31

kpollock

3,9999 gold badges44 silver badges67 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Non-Stored Procedure Query (CommandType=Text) with Dapper and parameters

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related