How to create array DbParameter[]

Question

The manual says that the ExecuteScalar method should be used like:

public T ExecuteScalar<T>( 
   string commandText,
   CommandType commandType,
   params DbParameter[] parameters
)

But how do I create that array of parameters? I need to provide my stored procedure 2 parameters.

Answer 1

• DbParameter is an abstract class.
• Since the type T can not be inferred from the usage, you have to specify it.

• Althought you can just pass a variable number of parameters without creating the array, if you are dynamically creating a variable number of parameters, the array is your friend.

  var parameters = new[]{
              new SqlParameter(){ ParameterName="foo", Value="hello" },
              new SqlParameter(){ ParameterName="bar", Value="World" }
          };
  x.ExecuteScalar<int>(commandText, commandType, parameters);
  

Answer 2

The parameters parameter has the params keyword. This means that you don't have to create the array explicitly but can pass a variable number of arguments to the method:

x.ExecuteScalar(commandText, commandType, parameter1, parameter2);

However, if you want, you can create the array explictly and pass it to the method as follows:

DbParameter[] parameters = new DbParameter[] { parameter1, parameter2 };

x.ExecuteScalar(commandText, commandType, parameters);