Splash Screen for loading data into ListView C#

Question

I created an application which loads data into a ListView by executing a procedure that is stored in SQL Server. The procedure takes some time to execute, when I click the button on application to execute the procedure my application just freeze until the data is loaded in the ListView.

How can I create a splash screen that loads when I press the button until the data is populated in the List View?

I appreciate any feedback.

public async Task<ListView> GetDataAsync()
        {
             var dt = new ListView();
             //var cn = @"Your Connection String";
             //var cmd = @"SELECT * FROM Category";
             //var da = new SqlDataAdapter(cmd, cn);
             SqlConnection conn = new SqlConnection();
             conn.Open();

             SqlCommand cmd = new SqlCommand("[Loyalty_Swipe]", conn);
             cmd.CommandType = CommandType.StoredProcedure;
             cmd.CommandTimeout = 0;
             SqlDataReader reader;

             cmd.Parameters.AddWithValue("@StartDate", txtStartDate.Text);
             cmd.Parameters.AddWithValue("@EndDate", txtEndDate.Text);
             cmd.Parameters.AddWithValue("@CustomerID", txtCustID.Text);
             reader = cmd.ExecuteReader();
             metroListView1.Items.Clear();

             await Task.Run(() =>
             {
                 while (reader.Read())
                 {

                     metroListView1.Columns[0].Text = "Date";
                     metroListView1.Columns[1].Text = "Store Code";
     ListViewItem listview = new   ListViewItem(reader["Date"].ToString());
                     listview.SubItems.Add(reader["StoreCode"].ToString());
                     listview.SubItems.Add(reader["StoreName"].ToString());
                     listview.SubItems.Add(reader["TillNumber"].ToString());
                     listview.SubItems.Add(reader["TranNumber"].ToString());
                     listview.SubItems.Add(reader["Amount"].ToString());
                     listview.SubItems.Add(reader["Discount"].ToString());
                  listview.SubItems.Add(reader["ProcessedFlag"].ToString());
                 listview.SubItems.Add(reader["Processed Date"].ToString());
                 metroListView1.Items.Add(listview);




                 };
             });
             conn.Close();
             pbLoad.Hide();
             btnExport.Enabled = true;
             return dt;
        }