How to pass an array into a SQL Server stored procedure

SQL Server 2008 (or newer)

 

CREATE TYPE dbo.EmployeeList
AS TABLE
(
  EmployeeID INT
);
GO

CREATE PROCEDURE dbo.DoSomethingWithEmployees
  @List AS dbo.EmployeeList READONLY
AS
BEGIN
  SET NOCOUNT ON;

  SELECT EmployeeID FROM @List; 
END
GO

DataTable tvp = new DataTable();
// define / populate DataTable from your List here

using (conn)
{
    SqlCommand cmd = new SqlCommand("dbo.DoSomethingWithEmployees", conn);
    cmd.CommandType = CommandType.StoredProcedure;
    SqlParameter tvparam = cmd.Parameters.AddWithValue("@List", tvp);
    tvparam.SqlDbType = SqlDbType.Structured;
    // execute query, consume results, etc. here
}