问c# sql命令中的语法错误

EN

SqlCommand cmd = getSQLCommand();
using (cmd.Connection)
using (cmd)
{
    try
    {
        string dbName = txt_DatabaseName.Text;
        var createDatabaseQuery = "exec ('CREATE DATABASE ' + @databaseName)";
        var sqlCommand = new SqlCommand(createDatabaseQuery, cmd.Connection);
        sqlCommand.Parameters.Add("@databaseName", SqlDbType.Text);
        sqlCommand.Parameters["@databaseName"].Value = dbName.ToString();

        cmd.Connection.Open();

        sqlCommand.ExecuteNonQuery();
    }
    catch (SqlException ex)
    {
        Console.WriteLine(ex.ToString());
        ScriptManager.RegisterClientScriptBlock(this, this.GetType(), "alertMessage", "alert('SQL Error. Record not added.')", true);
    }
    finally
    {
        cmd.Connection.Close();
    }
}