Array of Sized/Typed SqlParameters

Question

I'm trying to create an array of dbTyped and sized SqlParameters. This works fine but results in changing code both places if I need another column.

SqlParameter[] parameters = {
                                  new SqlParameter("@first_name", SqlDbType.VarChar, 50),
                                  new SqlParameter("@last_name", SqlDbType.VarChar, 50),
                                  new SqlParameter("@middle_name", SqlDbType.VarChar, 50),
                                  new SqlParameter("@empid", SqlDbType.Int)
                            };
parameters[0].Value = to.FirstName;
parameters[1].Value = to.LastName;
parameters[2].Value = to.MiddleName;
parameters[3].Value = to.EmpId;

What is a better way of doing this?

Answer 1

You can use object initializer expressions:

SqlParameter[] parameters =
{    
  new SqlParameter("@first_name", SqlDbType.VarChar, 50) { Value = to.FirstName },
  new SqlParameter("@last_name", SqlDbType.VarChar, 50) { Value = to.LastName },
  new SqlParameter("@middle_name", SqlDbType.VarChar, 50) { Value = to.MiddleName },
  new SqlParameter("@empid", SqlDbType.Int) { Value = to.EmpId }
};

You could also create a list in the same way, which is often preferred:

List<SqlParameter> parameters = new List<SqlParameter>
{    
  new SqlParameter("@first_name", SqlDbType.VarChar, 50) { Value = to.FirstName },
  new SqlParameter("@last_name", SqlDbType.VarChar, 50) { Value = to.LastName },
  new SqlParameter("@middle_name", SqlDbType.VarChar, 50) { Value = to.MiddleName },
  new SqlParameter("@empid", SqlDbType.Int) { Value = to.EmpId }
};

Or you could even write an extension method on SqlParameter:

public static SqlParameter WithValue(this SqlParameter parameter, object value)
{
    parameter.Value = value;
    return parameter;
}

Then use it like this:

List<SqlParameter> parameters = new List<SqlParameter>
{    
  new SqlParameter("@first_name", SqlDbType.VarChar, 50).WithValue(to.FirstName),
  new SqlParameter("@last_name", SqlDbType.VarChar, 50).WithValue = to.LastName)
  new SqlParameter("@middle_name", SqlDbType.VarChar, 50).WithValue(to.MiddleName),
  new SqlParameter("@empid", SqlDbType.Int).WithValue(to.EmpId)
};

Answer 2

You can use the constructor overload that allows you to specify the value as a parameter.

For example:

SqlParameter[] parameters = {
                              new SqlParameter("@first_name", SqlDbType.VarChar, 50, ParameterDirection.Input, true, 0, 0, "", DataRowVersion.Current, to.FirstName),

etc...

Answer 3

A better way? Sure: let a tool help you, for example "dapper":

var rows = conn.Query<YourType>(@" your tsql ",
    new { first_name = to.FirstName,
          middle_name = to.MiddleName,
          last_name = to.LastName,
          empid = to.EmpId }).ToList();

This then handles all the parameterisation and materialization for you.

Answer 4

you can add the value back like this:

 new SqlParameter("@first_name", SqlDbType.VarChar, 50).value = to.FirstName