Question

I have a winforms app that includes the following class method:

public aSqlQuery(SqlCommand pSqlCom, string pMode = "object", bool pGetID = false)
    {
        try
        {
            string strConnection = aSystem.ConnectionString;
            SqlConnection linkToDB = new SqlConnection(strConnection);
            pSqlCom.Connection = linkToDB;

            switch (pMode)
            {
                case "non query":
                    {
                        linkToDB.Open();
                        pSqlCom.ExecuteNonQuery();
                        if (pGetID == true)
                        {
                            SqlCommand sqlCom = new SqlCommand("SELECT @@IDENTITY;", linkToDB);
                            this.LastID = (int)sqlCom.ExecuteScalar();
                        }
                        linkToDB.Close();
                    }
                    break;

plus other switches

The pSqlCom (SqlCommand) executes fine becuase I can see the data written into the database. However the subsequent “SELECT @@IDENTITY” statement gives an invalid cast error
What am I doing wrong and how can I retrieve the new ID created by SQL within my class method?

Answer 1

The correct answer it turns out was that the SELECT SCOPE_IDENTITY() statement had to form part of the same SqlCommand as the INSERT statement which preceeded it, but which I had contained in the previous SqlCommand ‘pSqlCom’. Once the SELECT SCOPE_IDENTITY() was incuded as part of pSqlCom the code correctly returned the Identity.