select data from data grid view between two dates

[sashiksu]

I'm trying to select data between tow dates(values given by date time pickers) I try more. but can't go forward. here is my code :

Try
            If (con.State = ConnectionState.Closed) Then
                con.Open()
            End If
            cmd = New MySqlCommand("SELECT * FROM mcs.daily_income where date_received between @d1 and @d2", con)
            cmd.Parameters.Add("@d1", SqlDbType.DateTime, 30, "JoiningDate").Value = dtpstart.Value.Date
            cmd.Parameters.Add("@d2", SqlDbType.DateTime, 30, "JoiningDate").Value = dtpend.Value.Date
            da = New MySqlDataAdapter(cmd)
            ds = New DataSet()
            da.Fill(ds, "Staff")
            dgvreciept.DataSource = ds.Tables("Staff").DefaultView
            ds.Clear()
            da.Dispose()
            con.Close()
        Catch ex As Exception
            MessageBox.Show(ex.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
        End Try
        Dim ii As Integer
        Dim total As Decimal
        For ii = 0 To dgvreciept.Rows.Count - 1
            total = total + Val(dgvreciept.Item("Amount", ii).Value.ToString) ' or you can use Cint
        Next
        lbltdtotal.Text = total

my data grid view item's name : dgvreciept
date time pickers names :
1- dtpstart
2- dtpend

After selecting data I want to compute sum of amount field.
when I run this that give me error:
"Invalid cast from 'date time' to 'single' "

Please be kind to help my prob :)