datagridview to a CrystalReports

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C#

I have a problem in this code i want to Transfer the datas from DataGridView To Crystal Report
but have an error can anybody help me ???

this is my code :

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace test
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        DB db = new DB();
        DataSet ds;

        private void button1_Click(object sender, EventArgs e)
        {
            ds = db.ExecuteDataset(CommandType.StoredProcedure, "sp_user_list", "T", new SqlParameter[]
            {
                 new SqlParameter("@sex",comboBox1.Text)
            });
            dataGridView1.DataSource = ds.Tables["T"];
            dataGridView1.Columns[0].HeaderText = "کد کاربر";
            dataGridView1.Columns[1].HeaderText = "نام";
            dataGridView1.Columns[2].HeaderText = "نام خانوادگی";
            dataGridView1.Columns[3].HeaderText = "جنسیت";
            dataGridView1.Columns[4].HeaderText = "تلفن";
            dataGridView1.Columns[5].HeaderText = "آدرس";
        }

        private void button2_Click(object sender, EventArgs e)
        {
           crystalReportViewer1.Enabled = true;
           DataTable dt = new DataTable();
           dt = dataGridView1.DataSource as DataTable;
           ds.Tables.Add(dt);

           //error is in this line . it say the invenrep does not exist.
           invenrep.SetDataSource(ds);

           crystalReportViewer1.ReportSource = invenrep;//this line too            
        }
    }
}

how resolve this problem . what format must be define for " invenrep"???